Abstract Network
Guest Lectures
Student Lectures I
Student Lectures II
Student Lectures III
Student Posters
Alumni Presentations
Abstract Network
Guest Lectures
Student Lectures I
Student Lectures II
Student Lectures III
Student Posters
Alumni Presentations
Global challenges are more and more on the focus of today’s research community. We need strong basis of traditional sciences. However, this is not enough. We need additionally multidisciplinary research teams which approach relevant questions from many different angles. The research will be needed also to support basic decision-making processes. The physics and other natural sciences are fundamental to support societies that are all the time more and more complex and need highly developed skills in all the different fields.
The atmosphere forms a major part of the environment to which life on Earth is sensitively responsive. The atmosphere closely interacts with the biosphere, hydrosphere, cryosphere and lithosphere as well as with urban surfaces on time scales from seconds to millennia. Changes in one of these components are directly or indirectly communicated to the others via intricately-linked processes and feedbacks resulting in local, regional and global scale effects on climate and air quality. In recent years, substantial research has been motivated by the importance of atmospheric aerosols on the global radiation budget, cloud formation, and human health. Concentrations of reactive gases, greenhouse gases and atmospheric aerosol particles are tightly connected with each other via physical, chemical and biological processes occurring in the atmosphere, biosphere and at their interface. Human and societal actions, such as emissions-control policies, urbanization, forest management and land-use change, as well as various natural feedback mechanisms involving the biosphere and atmosphere, have substantial impacts on the complicated couplings between atmospheric aerosols, trace gases, greenhouse gases, air quality and climate.
One of the keys to understand what is going on in the atmosphere is to understand the formation of new aerosol particles. The production of molecular clusters and their growth to larger sizes, is a world-wide phenomenon, with a significant contribution to aerosol particle number load and indirect radiative effects as well as urban air pollution. Understanding the very initial steps of atmospheric aerosol formation requires detailed knowledge of the concentrations of neutral and charged clusters, on their chemical composition, and on the gaseous compounds participating in their formation and growth.
Actually, it seems that there is always more or less intensive clustering in the atmosphere but only some fraction of those clusters are able to growth to 3-4 nm and further to cloud condensation nuclei sizes. However, new particle formation is a major aerosol source affecting significantly to global aerosol and CCN load as well as global climate and regional/local air quality.
Superconducting quantum computers have reached the threshold for fault-tolerant quantum computing and shown scalability in two dimensions. Quantum supremacy is the next milestone on the way to large-scale quantum computers. I will review the concept of quantum computing and show how superconducting quantum bits can be built. Finally, I discuss the state of the Finnish quantum computer project.
What is the Universe fundamentally made out of? How did it all begin? What is the nature of Dark Matter and Dark Energy? These are some of the questions physicists are attempting to answer in particle physics. Dr Shaw will discuss the journey humankind has been on in exploring our universe, how new insights are changing the way we view the universe, and the role these findings play in society.
The world is increasingly digital but higher education is about human learning. So should we expect a disruption in higher education, as in music, movies and news media?
People -- and investors -- outside academia are still betting on disruptive technologies in transforming higher education. After the hype around massive open online courses there is hype in artificial intelligence and in blockchain technologies for education and the personalisation of education.
However, universities have been surprisingly resilient towards outside pressures throughout history. This talk is about two things in the future of higher education: is there a need to change, and how is the change possible. In order to answer those questions, multiple viewpoints are covered: students' incentives, teachers' incentives and organization's incentives (i.e. funding models).
| A: Soft matter & environment | B: Mathematical and gravitational physics | C: Quantum phenomena | D: Particle physics | E: Materials physics | |
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| Y122 D | 124 E | Y228a | Y228b | Aalto Hall | |
| 10:00 | David Bantje Interferometry on active emulsions | Trung Ha Quang Tight-binding realization of a non-Hermitian Hamiltonian | Daniele Nello How to flip a coin and get 100 times heads | Ben Jolitz Designing scalable Monte Carlo simulations in Python | Karel Kolář Development of scientific reasoning through challenging problems in competition "FYKOS" |
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Interferometry on active emulsionsDavid BantjeGeorg-August-Universität Fluid Mechanics Abstract Microswimmers are objects like bacteria or algae that can move through their liquid environment at low Reynolds numbers. They're thus of key interest in biology and potential medical applications work with artificial swimmers that could be used for precisely targeted drug delivery on microscopic length scales. To understand the underlying physics one needs a model system that can be accurately controlled in experiments and is simple enough so that links to analytical and numerical studies can be established while showing similar behaviour. A promising such system are liquid crystal droplets in an aqueous surfactant solution. We're currently setting up an interferometer to study the surface topography of droplets near walls. To reconstruct the topography we use phase images obtained by digital holography. In my talk I will present the current understanding of these active droplets, previous results and first interferometric measurements. |
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Tight-binding realization of a non-Hermitian HamiltonianHa Quang TrungNanyang Technological University Topological physics Abstract Recently there is great research interest in topological properties of non-Hermitian systems (with gain and losses). A recently published study looked at a non-Hermitian, two-dimensional continuum Hamiltonian and predicted zero-energy edge states characterized by two winding numbers. A realization of such a system is possible with a two-dimensional tight-binding lattice. This model can be used for computer simulation to verify the results obtained from study of the continuum limit. |
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How to flip a coin and get 100 times headsDaniele NelloUniversità di Torino Quantum Optics/Quantum Technologies Abstract In this presentation I am going to talk about the concept of weak measurement, which involves an interesting insight into the meaning of measurement in Quantum Physics and the foundations of the theory itself. It is an extremely powerful experimental procedure that enables to obtain directly the average value of an observable with a single measurement, using a week coupling of the observable with the system. With this technique it is possible to measure weak values, which imply a pre selection and a post-selection of the quantum state. They are unbounded in principle and can also be complex. |
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Designing scalable Monte Carlo simulations in PythonBen JolitzUCLA Computational physics Abstract Monte Carlo simulations are increasingly applied in physics. However, incorrectly implemented simulations can become unnecessarily computationally expensive. Understanding the concepts behind processes, memory, and I/O help researchers reduce simulation runtime. We will review best practices in software that are necessary for developing efficient Monte Carlo simulations. We will present a case study of a test particle simulation implemented in Python and demonstrate the efficacy of applying these concepts. |
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Development of scientific reasoning through challenging problems in competition "FYKOS"Karel Kolář et al.Charles University, Faculty of Mathematics and Physics Physics Education Abstract One of the most crucial aspects of physics competitions is the process of learning. Some contests, like FYKOS, have very much challenging problems, and participants have time for their solving. We bring examples of several exciting tasks from 31st year of FYKOS and a glimpse to some possibilities how to solve them. | |
| 10:15 | Ana Lomashvili Singularities of a frozen water droplet | Diana Popescu Production of scalar particles in magnetic fields on de Sitter space-time | Filip Sośnicki Comparison of spectral manipulation methods | Nikola Stupar Differential equation of motion and arrow of time | Daniel Dupkala Importance of Involvement of College Students in Highs School Physics Education via Activities of FYKOS |
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Singularities of a frozen water dropletAna LomashviliSan Diego State University Georgia Fluid dynamics Abstract A water droplet placed on a cool plate freezes into a singular pointy structure. The effect is observed because density of the liquid decreases after solidification. Therefore, the volume expands (vertically) and ends up with a pointy ice structure. Previously the phenomenon has been examined with a geometrical model but made assumptions did not give the conical top if we used the liquid-solid density ratio that is typical for water. Therefore, we neglected some simplifications and studied freezing process deeply. We investigated the details about heat transfer, size of a droplet, and formation of ice crystals. Our experimental and theoretical results gave a good agreement with each other. The first observed fact was that transfer of heat is more intense at the edges thus they freeze first. We also investigated the relationship between the size of a droplet and formation of a pointy ice structure. According to the Bond number, we found the maximum size of a droplet. The limitation of a droplet size was caused by surface tension. It should overcome the weight of the droplet in order to form a droplet and the expansion of the volume was vertical and not radial. (if there was radial expansion, the droplet would not freeze into a pointy ice structure) Finally, we investigated the formation of ice crystals from vapor molecules that were moving towards frozen ice drop. Experimental results showed that ice crystals are formed more intensively around the pointy top that is because of high diffusion of vapor. All the experiments are compared to the theoretical assumptions and they are in good agreement with each other. |
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Production of scalar particles in magnetic fields on de Sitter space-timeDiana PopescuWest University of Timisoara Theoretical Physics Abstract The production of scalar particles by the dipole magnetic field on de Sitter expanding universe is analyzed. The amplitude and probability of transition are computed using perturbative methods. A graphical study of the transition probability is performed obtaining that the rate of pair production is important in the early universe. Our results prove that in the process of pair production by the external magnetic field the momentum conservation law is broken. We also found that the probabilities are maximum when the particles are emitted perpendicular to the direction of the magnetic dipole momentum. The total probability is computed and is analyzed in terms of the angle between particles momenta. |
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Comparison of spectral manipulation methodsFilip SośnickiUniversity of Warsaw Quantum optics, spectral manipulation, pulse compression, electro-optic phase modulation Abstract The most promising approach to create a useful quantum information processing system is to use a hybrid quantum network [1] composed of quantum devices – nodes, interconnected with photonic links. Nodes of such network can consist of spontaneous parametric down-conversion (SPDC) sources of heralded single photons or entangled photon pairs, NV centers, quantum dots, atomic ensembles for quantum memories and many others. Different kinds of nodes will allow for different types of operations, especially creating quantum states of light and manipulating them, while photonic links will be responsible for nondisruptive sending quantum states of light. However disparate quantum devices shows different spectro-temporal characteristics. The spectral incompatibilities of them result in reduced efficiency of interconnecting them or even forbid a quantum network to operate. For such variety of quantum devices in the network the challenge arises to change both central wavelength and spectral bandwidth of interconnecting photons to match the required characteristic for different types of nodes. During my presentation I will introduce an idea of hybrid quantum network and show main spectro-temporal challenges. Then I will review different methods of manipulating of central wavelength or spectral bandwidth or both. They include especially nonlinear optics methods such as sum frequency generation (SFG) [2] and electro-optic phase modulation (EOPM) [3]. I will show state of the art of spectral manipulation of quantum light and discuss their abilities, as well as pros and cons. References: [1] H. J. Kimble, “The quantum internet”, Nature 453, 1023–1030 (2008). [2] J. Lavoie, J. M. Donohue, L. G. Wright, A. Fedrizzi, and K. J. Resch, “Spectral compression of single photons”, Nat. Photonics 7, 363–366 (2013). [3] M. Karpiński, M. Jachura, L. J. Wright, and B. J. Smith, “Bandwidth manipulation of quantum light by an electro-optic time lens”, Nat. Photonics 11, 53–57 (2017). |
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Differential equation of motion and arrow of timeNikola StuparUniversity of Banja Luka Computational physics Abstract In classical mechanics, evolution of a system is described by differential equations of motion. Laws of classical mechanics are time symmetric. Same set of equations can be used to describe motion along the path forward in time and motion along the same path backwards in time. Both of these motions are possible when it is looked at motions themselves. Thermodynamic concept of the arrow of time that would suggest obvious direction of time when observing these two motions cannot be seen. Arrow of time cannot be seen in differential equation of motion, but it is obvious in real life. In this paper, results of computational experiment are presented. Differential equation of motion that describes oscillatory motion of particle is observed. In some time period, 110 values of particle position were calculated. Complexity Cmp was calculated for this time series. As the time passes, complexity Cmp is increasing. Values of Cmp are scattered, but correlation of increasing Cmp with increasing time step is seen. Time in which computer is performing calculation has a certain direction, which is consistent with the arrow of time. When using negative time step, Cmp is decreasing with increase of time step. Numerical solution of this differential equation does not depend of the sign of the time step. It is seen that when numerically solving differential equation of motion, arrow of time emerges. |
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Importance of Involvement of College Students in Highs School Physics Education via Activities of FYKOSDaniel DupkalaFaculty of Mathematics and Physics, Charles University Physics Education and Science Propagation Abstract Nowadays, high school students do not have the motivation to study the physics. In Slovakia or the Czech republic this problem is partially caused by small number of teachers of Physics. The subject is often taught by teachers who do not have even the basic physics education. Therefore it is necessary to give the students other possibilities to get in touch with physics. As they are usually passionate into physics and have more then basic understanding of the problematic, college students can be successful to motivate high school students to study Physics. FYKOS is a group of students of Faculty of Mathematics and Physics at Charles University. They organize various activities for high school student, such as the internet competition which runs during the whole academic year. Students have several weeks to solve 8 various problems six times during the year. Their solutions are corrected and sent back. The best participants get to attend a special physics camp which is organized twice a year. FYKOS also organize Physics Brawl and Online Physics Brawl - team competitions where the goal is to solve as many problems as possible in 3 hours. Other activities organized by FYKOS are lectures and excursions to university laboratories and international research facilities such as CERN. The results of these activities are described in the talk. | |
| 10:30 | Verena Markmann Micro Jet Applications | Julia Lange Infinite-dimensional Marsden-Weinstein reduction in quantum mechanics | Tomasz Necio Geometrical stress effects studied with use of inelastic light scattering techniques | ||
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Micro Jet ApplicationsVerena MarkmannDESY Photon Science Abstract Water guns and their liquid jets are known by every child today. But as early as in the 15th century Leonardo da Vinci experimented with jets formed by water, break up processes into droplets and the influence of viscosity. Today’s scientific interest concentrates on sub millimeter jets. They are convenient for sample delivery systems at x-ray facilities, because radiation sensitive samples are illuminated only for fractions of a second. Furthermore liquid jets achieve shear rates that exceed the ones in conventional (plate-plate, Couette) geometries by 2-3 orders of magnitude and therefore become interesting for rheology measurements. Why microjets? How to create them and some interesting experiments done with jets will be presented in this talk. |
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Infinite-dimensional Marsden-Weinstein reduction in quantum mechanicsdr hab. Javier de Lucas Araujo, Julia LangeUniversity of Warsaw Mathematical Physics/Theoretical Physics Abstract This talk aims to introduce the theory of infinite-dimensional manifolds and to provide a rigorous approach to several mathematical and physical models using this theory. In particular, special attention is paid to the infinite-dimensional Marsden-Weinstein reduction and its application to the study of reduction process of a separable Hilbert space onto its projective one. Our new approach intends to describe the reduction of Schrodinger equation determined by time dependent self-adjoint operators, onto the projective space. In contrast to other approaches in the literature, our techniques are based upon generalisations of methods from functional analysis to differential geometry. |
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Geometrical stress effects studied with use of inelastic light scattering techniquesTomasz Necio, Daniel Navarro-Urios, Jeremie Maire, Martin Colombano Sosa, Clivia Sotomayor-TorresUniversity of Warsaw Optomechanics Abstract Brillouin light scattering is a phenomenon arising from photon–phonon interactions. Measuring the energies of Stokes and Anti-Stokes photons might be used as a technique to characterise the bulk acoustic modes of a material. Optomechanical coupling of light to optical resonator modes allows for transduction of thermally activated mechanical modes. Spectroscopy of light re-radiated from the resonator directly reveals its mechanical eigenfrequencies. We studied geometrical stress effects on the elastic properties of glass microspheres using developed technique. We find a difference in elastic properties between material in bulk form and embedded in microspherical geometry. We also compare obtained results with theoretical predictions. Catalan Institute of Nanoscience and Nanotechnology | |||
| 10:45 | Ekaterine Dadiani Singing paper strip | Temo Khvedelidze Liuovilie Theory | Frane Lunić The effect of disorder on superfluidity in one-dimensional Bose systems | Alexander J. Pfleger Machine Aided Classification of (Audio) Signals | Daniel Lozano Physicist AS consultants: just don't |
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Singing paper stripEkaterine DadianiTbilisi State University Aerodyamics Abstract We consider the problem of paper strip (blade of grass) producing various sound by blowing across it. While blowing across the paper (grass), it starts vibrating, causing air around it vibrate. These vibrations are carried through the air to our ears, where we hear them as sound. To explain the phenomenon two possible causes were considered. One of the possible cause is vortex induced vibration, which this paper will show to be insignificant. (Because of further observation that air flow velocity doesn’t have effevt on frequency, explained both theoretically and experimentally) Instead, the actual mechanism responsible for the sound production is aeroelastic flutter similar to that of aeroplane wings. Produced sound dependence on relevant parameters (such as Tension, Length, Width, Surface density, Length density, air velocity) is examined both theoretically and experimentally and they give a good agreement with each other. So the main peculiarity of this problem is the explanation and investigation of sound frequency and amplitude. Frequency of sound induced from vibration is found theoretically according to wave equation. Using Fourier transform, sound picks are examined on different cases, so empirical equation of sound frequency is also found experimentally. Theoretical assumptions are in good agreement with experiments. Amplitude is of the sound is chaotic, simulation of different vibrions were made using 'Matlab'. |
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Liuovilie Theorytemo khvedelidzetbilisi freeuniversity Theoretical physics Abstract -Geometrical and physical interpretation Our aim is to describe the geometrical picture related to the Liouville equation and present its possible physical interpretation. We will show that Liouville theory describes 2d space-time with constant curvature and we interpret it as a model of 2d gravity. We will describe the symmetries of the Liouville equation related to its geometrical picture and show how these symmetries de ne the general solution of the nonlinear eld equation. We then consider particle dynamics in the Liouville eld. To describe the geometrical picture related to Liouville theory, we rst introduce the notion of curvature for 2d surfaces embedded in R3. |
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The effect of disorder on superfluidity in one-dimensional Bose systemsFrane Lunić, Leandra Vranješ MarkićUniversity of Split Cold gases Abstract One-dimensional (1D) behavior can be achieved in realistic systems by restricting particle motion in two spatial directions. If particle interaction is present, the physics in 1D can differ profoundly from the physics in higher-dimensional systems. We present the results of a numerical study of 1D systems of interacting bosons. Our main aim was to explore the effect of disorder on superfluidity in systems of cold interacting bosons in the Tomonaga-Luttinger liquid (TLL) regime. Superfluidity is the property of flow without resistance, which requires the presence of extended particle states. Generally, disorder tends to cause state localization, thus suppressing superfluidity. The low-energy properties of a TLL are in part determined by the value of the Luttinger parameter, and it has been predicted that superfluidity is robust to disorder above a certain critical value. Below the critical value, even weak disorder is expected to cause localization, resulting in an insulating Bose glass phase. Our results support the existence of localized and superfluid phases, however, the details of the dependence of superfluid fraction on the product of system length and temperature require further interpretation. |
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Machine Aided Classification of (Audio) SignalsAlexander J. PflegerTechnical University ofGraz Acoustics, machine learning, experimental physics Abstract Contemporary measurement setups generate enormous amounts of data. Prior to the evaluation the data needs to be sorted with regard to abnormalities. Performing this process by hand is usually time consuming and sometimes impossible. Therefore an automated categorization is inevitable. In this work a possible attempt for sorting signals and similar data is shown. Audio signals are used in order to verify the effect of the method easily. In particular excerpts from songs and music pieces are assigned to different musical genres. In order to classify a given sound file features are extracted that contain abstract information about the shape of the signal, occurring frequencies and rhythmical properties. By comparing those features for different signals and different genres, patterns can be found. These patterns are used to categorize an unknown signal. |
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Physicist AS consultants: just don'tDaniel LozanoUniversity of Barcelona Economy Abstract The aim of this lecture is to explain what is the daily routine of a consultant. Physicists are known to develop during their career a notorious capacity of adapting to new environments, and one of them could possibly be working for a consultancy and selling your soul to the devil. I will try to explain my personal experience working for one of theses companies and why it is the worst decision I haver ever made. | |
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| 11:15 | David Reinisch Electrochemical CO2 Reduction | Folkert Nobels Modified potentials in infinite derivative gravity theories | Tatiana Kormilina Beyond quantum dots: a dive into the world of different shapes, heterostructures and supercrystals | Ana Luisa Carvalho Machine Learning applied to High Energy Physics | Pawel Wojcik Optical absorption in laser-driven far-from-equilibrium system |
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Electrochemical CO2 ReductionDavid Reinisch, Harald Landes, Nemanja Martic, Bernhard Schmid, Ralf Krause, Karl Mayrhofer, Günter SchmidFAU Chemical Physics Abstract The strong rise of renewable energy sources for electricity generation has challenged the way traditionally dealt with. One of the biggest questions is how to deal with the big volatility of their generation. A popular approach is the electrochemical conversion of electric energy into hydrogen and back. However so far this solution has suffered from low round-trip efficiencies and high system costs. Another idea is using this excess energy to create valuable products directly. A possible mechanism for this is the electroreduction of CO2. Some possible products are CO or ethylene which can be used for further synthesis in the chemical industry. The mechanisms for this have been investigated for some time, but real world imp lementation still needs improvements in areas such as stability and efficiency. After an introduction of the fundamentals of electrochemistry this talk aims to show the challenges when converting an academic lab discovery into a product and how these problems are met. |
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Modified potentials in infinite derivative gravity theoriesFolkert NobelsUniversity of Groningen/Kapteyn Astronomical Institute/Van Swinderen Insitute Astrophysics: galaxy formation and evolution Abstract Over the last 100 years, general relativity has been established as one of the most widely accepted theories. A huge number of experiments have been done to test it to a very high precision. The first tests of general relativity were adopted in the solar system. By correctly predicting the gravitational lensing produced by the sun and the perihelion motion of mercury, this led to a widely accepted theory. Over the next 100 years, more experiments such as gravitational waves verified general relativity. Despite the enormous success of this theory, it has several shortcomings at short distances, deeming it incomplete. These include black hole singularities, which result in inappropriate limits of the potential at small distances, and serious problems at the quantum level which render general relativity non-renormalizable. In this thesis, the first approaches to making the theory renormalizable and removing the singularities are discussed. This can be achieved by including higher order derivatives. The simplest extensions of general relativity are $f(R)$ gravity, Conformal invariant gravity and Stelle gravity. These theories modify the action by including the square of the Ricci scalar and/or a squared Ricci tensor besides the Ricci scalar itself. Of the simplest extensions, only Stelle gravity removes singularities. Despite this success, Stelle gravity produces a ghost which makes the theory non-unitary and therefore unphysical. A possible solution to this problem is introducing an action which contains an infinite-order amount of derivatives combined with all possible contractions with the Ricci scalar, Ricci tensor and the Riemann tensor. Some of these theories are able to remove singularities while others still have them but remain ghost free. In this thesis, several different classes of these theories are discussed in which they are generalized for more situations than appear in the literature. In general, when introducing no additional particles the singularities of gravity are removed, of these theories only one specific subclass of theories seem to have a non-oscillating potential. Furthermore when an additional particle is introduced in the theory, the singularities will not be removed and the behavior will always tend towards the behavior of a Yukawa potential. A finite number of additional particles will not remove the singularity but a model that includes an infinite amount of particles will. |
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Beyond quantum dots: a dive into the world of different shapes, heterostructures and supercrystalsTatiana Kormilina, Sergei Cherevkov, Evgeniia Stepanidenko, Elena UshakovaITMO University Nanomaterials, nanotechnology, photonics Abstract Several decades ago the world was changed by an invention of the semiconductor nanomaterials with unique optical properties introduced by quantum effects. When the chemical approaches allowed to make colloidal free-standing nanocrystals, those turned out to be nearly universal. Quantum dots, as they were named, found applications in various fields from biological imaging and drug delivery to new-generation lasers, video displays and solar cells. Now, as nanocrystals became more common and evolved from a research novelty to an industrial product, the new research directions emerged that are far more deep and diverse. We can now control the shape of nanocrystals and take advantage of the different types of quantum confinement. Two-dimentional nanocrystals called nanoplatelets proved to be even more suitable for optoelectronic applications by some of their optical parameters. We also learned to combine different nanomaterials to create synergetically advanced heterostructures and complexes. Namely, the shell of a second semiconductor enhances stability and allows control of the nanocrystal’s properties with the impact of heterojunction. And complexes of semiconductor nanocrystals with metallic nanoparticles show great photoluminescence enhancement. We found out that nanocrystals can self-assemble into microscopic superstructures with many different variations and features and managed to gain control over this process. Here our group presents the results of several research projects that we have conducted to investigate various nanocrystal-based structures and reveal their optical properties. We think that our research will help to understand some fundamental processes in nanosystems and expand the toolkit of functional nanomaterials for photonics. |
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Machine Learning applied to High Energy PhysicsAna Luisa Moreira de CarvalhoUniversidade Nova de Lisboa - Instituto Superior Técnico Computer Science, Particle Physics Abstract In particle physics, separating the process we want to measure, the signal, from all the other processes that can happen simultaneously, the background, is of the utmost importance. Traditionally this is done by placing cuts on kinematic variables in order to isolate regions of the parameters space where there is more signal than background. While this approach works well in many analysis it begins to fail when we try to study processes with very small cross sections and for which the backgrounds completely dominate. In this cases we can’t afford to discard a lot of signal because we already have so few signal events. Given this scenario, deep learning techniques such as decision trees and neural networks provide a cutting edge alternative to the traditional cut based analysis. |
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Optical absorption in laser-driven far-from-equilibrium systemPaweł WójcikUniversity of Warsaw AMO Abstract The talk will present new results in the theoretical study of solids in an intensive, non-resonant laser fields. The time dependent character of Hamiltonians which incorporate the electromagnetic field of laser poses problems to the traditional methods. We have introduced a new approach for understanding of an optical absorption. Application of the Floquet theory enabled us to find propagator in a systematic manner. The application of our method to selected system will be presented. There will be also presented brief summary of experimental results in the field. The great progress in atomic, molecular and optical physics was achieved thanks to the tight cooperation of experiment with theory – a feat which not many fields can be proud of. At the heart of this field lies the theory and application of lasers. Nowadays lasers are widely accessible and have made an incredible progress since their discovery. Current years is the time when their application to new technologies is already present and will grow in importance. | |
| 11:30 | Maija Peltola Underlying reasons of particle number concentration biases in a global aerosol climate model | Florian Wolz Covariant constructive gravity: The bootstrap approach | Pawel Matus Dynamics of n:2 resonances of atoms bouncing on an oscillating mirror: toward a new class of time crystals | Matthias Dahlmanns Simulations in Stellarator Physics | Teodor Duevski Grain Boundary Effects in Halide Perovskites |
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Underlying reasons of particle number concentration biases in a global aerosol climate modelM. Peltola, P. Paasonen, F. Xausa, R. Makkonen, and M. KulmalaUniversity of Helsinki Aerosol physics, climate modelling Abstract Aerosol particles are tiny liquid and solid particles floating in the air everywhere around us. As the role of aerosols is currently the biggest single uncertainty in predicting the future climate, more information is needed on aerosols and their interactions with clouds and climate. Here, we study how well the global aerosol-climate model ECHAM5.5-HAM2 (Stier et al., 2005; Zhang et al,. 2012) predicts the concentrations of aerosol particles by comparing the model results to ambient measurements done in different environments around the world. To see which phenomena are important when predicting the particle number concentrations, we use the model with three different configurations. We use two different microphysical modules to describe the aerosol population and two different emission scenarios to describe the emissions from human activities. The results from different model runs are then compared to particle number concentrations calculated from measured particle number size distributions in dozens of different sites around the world. We focus on particles with diameters above 50 or 100 nm (N50 and N100) because these diameters represent the minimum diameters of particles that are able to influence the formation and properties of clouds in different environments and thus affect the climate indirectly (Kerminen et al., 2012). To further analyse why the concentrations differ between the model and measurements, we use also other data such as temperature, chemical composition of the particles and predicted anthropogenic emissions to explore the reasons for the particle number biases. Temperature could be used to explain the differences between modelled and observed concentrations, because many of the processes affecting the particle population are temperature dependant (Scott et al., 2018). As for most measurement places only particle and temperature data is available, we use also modelled data of anthropogenic emissions to track down reasons for modelled particle number biases. This far we have observed that for most places the modelled number concentrations differ substantially from the measured concentrations and there are clear differences between the different model setups. We are continuing the work on determining the reasons that are causing these biases. In the future this method can be used to reduce the uncertainties in climate models. Stier P. et al. (2005). Atmospheric Chemistry and Physics, 5:1125–1156 Zhang K. et al. (2012). Atmospheric Chemistry and Physics, 12:8911–8949 Kerminen V.-M. et al. (2012). Atmospheric Chemistry and Physics, 12:12037–12059 Scott C. et al. (2018). Nature Geoscience 11:44-48. |
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Covariant constructive gravity: The bootstrap approachFlorian WolzFriedrich-Alexander University Erlangen Modified Gravity Theories Abstract In recent years it was shown that, building on the principle of coordinate independence, one can derive the dynamics of any geometry. Although always possible in principle, it proves technically quite difficult to actually obtain an exact solution. Still, one can always calculate perturbative solutions to arbitrary order, which provides a suitable approximation for almost all practical considerations. In this talk, the converse question will be discussed. Namely, if we naively derive the weak field dynamics of a field propagating on a flat background, can we obtain by a self-coupling of this field by first principles, as gauge invariance and energy-momentum conservation, the full gravitational dynamics? |
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Dynamics of n:2 resonances of atoms bouncing on an oscillating mirror: toward a new class of time crystalsPaweł MatusJagiellonian University in Krakow Quantum/Condensed Matter Physics Abstract A system composed of atoms bouncing on a harmonically oscillating, horizontal plane has been recently investigated as a simple system, in which discrete time symmetry breaking can be observed. Floquet eigenstates of such a system evolve with the same period, with which the plane vibrates, but interaction between the atoms can lead to a spontaneous breaking of this symmetry and formation of a so-called discrete time crystal. So far, however, attention has been paid only to first-order n:1 resonances, where the period of the new motion is a multiple of the period of the driving. Here we focus on second-order non-integer n:2 resonances. We analyze the motion of the particles classically and derive an effective hamiltonian, which governs their behaviour. We then use a semiclassical approximation to find eigenstates of the hamiltonian. The obtained results hint at a possible discovery of novel phenomena in a fully quantum-mechanical treatment. |
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Simulations in Stellarator PhysicsMatthias DahlmannsUniversität zu Köln Plasma Physics Abstract Almost unlimited, emissionless, save and everywhere accessible energy without long-lived waste. What sounds like a dream is currently under construction: in Southern France, the first fusion power plant test reactor - ITER - is already halfway finished. Meanwhile, in the very Northeast of Germany, an other machine is working on bringing the stars to Earth: Wendelstein 7-X (W7-X). ITER and W7-X are each the largest experiments of the two most promising concepts for a power plant: The tokamak (ITER) on one hand and the stellarator (W7-X) on the other hand. The tokamak is - thanks to its toroidal symmetry - today the more developed concept. However, stellarators offer various advantages compared to tokamaks, such as the possibility of steady state operation. The mission of W7-X is to show that stellarators are keeping this promise and the fascinating results of the first measuring campaigns of W7-X show that it works very well so far. Nevertheless, a stellarator is still a challenge for numerical simulations since its magnetic field is 3-dimensional and carries various features. |
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Grain Boundary Effects in Halide PerovskitesTeodor DuevskiUniversity of Helsinki Nanoscale Solar Cells Abstract Grain boundaries play a key role in the performance of thin-film optoelectronic devices and yet their effect in halide perovskite materials is still not understood. The biggest factor limiting progress is the inability to identify grain boundaries; the gold standard – electron backscattering diffraction (EBSD) – destroys halide perovskite thin films. Non-crystallographic techniques commonly misidentify grain boundaries, leading to conflicting literature reports about their influence. Here we solve this problem using a solid-state EBSD detector with 6,000 times higher sensitivity than the traditional phosphor screen and camera. Correlating true grain size with PL lifetime, carrier diffusion length and mobility shows that grain boundaries are not benign but have a recombination velocity of 1670 cm/s, comparable to that of crystalline silicon. However, as with silicon, amorphous perovskite can passivate crystalline boundaries, leading to bright photoluminescence and longer carrier lifetime without reducing diffusion length. This variable gain boundary character offers a possible explanation for the mysteriously long lifetime and record efficiency achieved in small grain halide perovskite thin films while pointing the way forward to even better performance. | |
| 11:45 | Lili Farkas The Effect of Wet Deposition on Ground-Level Gamma Dose Rates | Serena Giardino Black Holes as Bose-Einstein condensates of gravitons: a new perspective | Tomasz Szołdra Harper-Hofstadter Model | Patrick Lainer An Iterative Approach to Non-Axisymmetric Perturbations in Tokamaks | Timo Eckstein Inelastic pondermotive scattering of electrons at an optical travelling wave – a GeV/m free space compression and acceleration scheme |
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The Effect of Wet Deposition on Ground-Level Gamma Dose RatesLili FarkasEötvös Loránd University Meteorology, environmental physics Abstract In this study we examine the contribution of the natural radioactivity of the rain to the gamma dose detectors of a nuclear environmental monitoring system that consists of gamma dosimeters at 1 m above the ground around a nuclear power plant. Our aim is to determine the relationship between rainfall and the dose increase associated with them. |
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Black Holes as Bose-Einstein condensates of gravitons: a new perspectiveSerena GiardinoAlma Mater Studiorum - University of Bologna General Relativity: Black Holes Abstract The motivation for this work stems from the idea of Dvali and Gomez that the end state of a gravitational collapse is a Bose-Einstein condensate at the critical point, with a large occupation number of soft gravitons. The approach is innovative since it moves away from the semi-classical picture of black holes and considers black holes as purely quantum objects. Recently, it has been shown that including the effect of soft gravitons in the description if the gravitational collapse allows to correctly reproduce the expected post-Newtonian correction to the potential energy and Bekenstein's area law. In this scenario, the collapse does not produce a central singularity. The condensate can then be described using two Gross-Pitaevskii equations for a static and spherically symmetric configuration, corresponding to the constraint minimisation of the hamiltonian with respect to the redshift and to the gravitational potential. This thesis will further investigate the relationship between the previously employed post-Newtonian approximation and the Gross-Pitaevskii equations. |
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Harper-Hofstadter ModelTomasz SzołdraJagiellonian University Condensed matter, theoretical physics Abstract In a sufficiently strong uniform magnetic field, for charged particles in a 2D square crystal lattice an interesting effect occurs: as a function of applied magnetic field, the energy levels form a fractal structure known as Hofstadter's butterfly. Moreover, energy bands possess non-trivial topological properties. I will show a theoretical insight into this model. |
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An Iterative Approach to Non-Axisymmetric Perturbations in TokamaksPatrick Lainer, Christopher AlbertGraz University of Technology Theoretical Plasma Physics Abstract A tokamak is a usually axisymmetric device used to confine plasma in a strong magnetic field with the goal to produce energy from nuclear fusion. To avoid edge instabilities, so-called edge-localized modes, this axisymmetry is intentionally perturbed by magnetic fields from external coils. Here a magnetohydrodynamic model is used where the plasma is treated as a fluid in thermal equilibrium that is influenced by magnetic forces. Starting from an axisymmetric equilibrium, a perturbation is imposed to linear order and the plasma response pressure and currents are computed based on a given perturbation field. This computation is iteratively coupled to a finite-element solution of Maxwell's equations yielding fields produced by the plasma currents. At certain positions inside the plasma, so-called resonant surfaces, the perturbation is in resonance with the pitch of the equilibrium magnetic field, causing large plasma currents. Those act as shielding currents, preventing the perturbation to penetrate further inside the plasma. While an accurate prediction of this behaviour requires a kinetic model, away from the resonant surfaces the described ideal magnetohydrodynamic model is valid. It can be used as a drop-in replacement to benchmark and to complement the more computationally intensive kinetic computation. |
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Inelastic pondermotive scattering of electrons at an optical travelling wave – a GeV/m free space compression and acceleration schemeMartin Kozak, Timo Eckstein, Norbert Schönenberger and Peter HommelhoffFAU Erlangen Laser Physics Abstract In the early days of quantum mechanics Kapitza and Dirac predicted that matter waves would scatter of the optical intensity grating formed by two counter-propagating light waves1.This interaction, driven by the ponderomotive potential of the optical standing wave, was both studied theoretically and demonstrated experimentally for atoms2 and electrons3–5.In the original version of the experiment1,5 , only the transverse momentum of particles was varied, but their energy and longitudinal momentum remained unchanged after the interaction. Here, we report on the generalization of the Kapitza–Dirac effect. We demonstrate that the energy and the forward momentum of sub-relativistic electrons are strongly modulated on the few-femtosecond timescale via the interaction with an optical travelling wave created in vacuum by two pulsed laser beams impinging on the electron beam under properly chosen angles and with two different frequencies6,7. This effect extends the possibilities of temporal control of freely propagating particles with coherent light and can serve for attosecond ballistic bunching of electrons8, or for the acceleration of neutral atoms or molecules by light. Electron pulse trains with pulse durations below 300 attoseconds have been experimentally demonstrated. These can be utilized for time-resolved imagining with sub-femtosecond resolution. References: 1. Kapitza, P. L. & Dirac, P. A. M. The reflection of electrons from standing light waves. Proc. Camb. Phil. Soc. 29, 297–300 (1933). 2. Gould, P. L., Ruff, G. A. & Pritchard, D. E. Diffraction of atoms by light: the near-resonant Kapitza–Dirac effect. Phys. Rev. Lett. 56, 827–830 (1986). 3. Bucksbaum, P. H., Bashkansky, M. & McIlrath, T. J. Scattering of electrons by intense coherent light. Phys. Rev. Lett. 58, 349–352 (1987). 4. Bucksbaum, P. H., Schumacher, D. W. & Bashkansky, M. High intensity Kapitza–Dirac effect. Phys. Rev. Lett. 61, 1182–1185 (1988). 5. Freimund, D. L., Aflatooni, K. & Batelaan, H. Observation of the Kapitza–Dirac effect. Nature 413, 142–143 (2001). 6. Kozák, M. , Eckstein, T. , Schönenberger, N. & Hommelhoff, P., Inelastic ponderomotive scattering of electrons at a high-intensity optical travelling wave in vacuum, Nat. Phys. 14, 121 (2018). 7. Kozák, M., Schönenberger, N. & Hommelhoff, P., Phys. Rev. Lett. 120, 103203 (2018). 8. Baum, P. & Zewail, A. H. Attosecond electron pulses for 4D diffraction and microscopy. Proc. Natl Acad. Sci. USA 104, 18409–18414 (2007). |
| A: Medical physics and biophysics | B: Astrophysics | C: Quantum phenomena | D: Particle physics | E: Materials physics | |
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| Hall 6 | Hall 7 | Hall 8 | Hall 10 | Hall 12 | |
| 10:00 | Maria Katsiampa Cancer: A Physicist’s View | Erik Johnson Stellar Activity and Exoplanet Detection | Holger Ribergaard Heebøll Describing quantum optics experiments using a quantum field theory | Tamas Almos Vami Search for long-lived particles with the CMS detector at CERN | Ewelina Nowak Optical investigation on zinc oxide for optoelectronic application |
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Cancer: A Physicist’s ViewMaria KatsiampaUniversity of Crete Medical Physics Abstract High energy and particle physics are fields that contribute to our understanding of cosmos in an atom’s dimension. However they also play a distinctive role in medical research, contributing to understanding the mechanisms of human body, disease imaging and treatment. Cancer is a major research topic for scientists, as 9 million people die approximately each year worldwide. Physics might seem irrelevant to cancer for some, yet constitute a “game changer” in cancer treatment and screening. The current most popular treatment methods are chemo and radiotherapy, which in most cases lead to severe side effects. Particle and high energy physics are creating a fertile ground to innovating cancer therapies that will eliminate the risk of conventional ones, as medical physicists use particles -other than electrons- to extinguish tumours, taking advantage of the particles’ properties. This talk will present what is cancer, the role of physics in cancer screening (what are and how do PET, MRI, CT , operate) and treatment (How do chemo, x-ray, proton, carbon ion therapies work, the advantages, disadvantages and challenges). |
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Stellar Activity and Exoplanet DetectionErik JohnsonInstitute fur Astrophysik Gottingen/ Max Planck Institute for Solar System Research Astrophysics - Stellar Activity/Exoplanets Abstract Stellar activity has long been an issue for researchers attempting to discover new exoplanets. At first this consideration limited research efforts to older K G F type stars that are fairly quiescent. However, due to limitations of current technology, we are not capable of detecting Earth-like planets in Earth-like orbits about them. We can, however, detect this type of world around the much less massive M stars but these stars are among the most active stars known. It is therefore imperative to be able to separate out which effects of stellar activity are the dominating factor in disrupting a planetary radial velocity signal. The main aspects of stellar activity that we will be looking at this talk will be spots, plage and flares/CMES and what the current state of the field is. |
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Describing quantum optics experiments using a quantum field theoryHolger Ribergaard HeeboellUniversity of Southern Denmark Quantum optics and effective field theory Abstract Recent studies in very energetic Rydberg states in atoms has demonstrated the possibility of strong interactions between as few as two photons. This project investigates recent quantum field theory approaches to describe the quasi-particles called Rydberg polaritons in these systems The Hamiltonian for the quantum optic system of ladder EIT was derived in terms of field operators and transformed to effective transition fields. The quasi-particles called Rydberg polaritons was found to be the mass-eigenstates of the ladder EIT setup. The interaction of Rydberg polaritons with an external field was modeled by a quadratic interaction term. The corresponding Feynman diagrams and the resulting equation for the T-matrix were presented. The interaction of two Rydberg polaritons was modeled by a quartic interaction term and the resulting Feynman diagrams and T-matrix were presented. The resulting system in an appropriate limit was a single particle propagating through an effective potential. |
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Search for long-lived particles with the CMS detector at CERNTamas Almos VamiEotvos Lorand University High Energy Physics Abstract In this talk, a search for Physics beyond the Standard Model using the CMS detector at CERN will be presented. We are looking for long-lived charged particles that decay within the CMS detector and produce the signature of a disappearing track. A disappearing track is a track that has hits only in the inner tracker and nowhere else. The results of the search are interpreted in the context of anomaly-mediated supersymmetry (SUSY) breaking. As a conclusion of the talk, we will set limits for mass of the the lightest SUSY particle with the lifetime of 3 ns. |
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Optical investigation on zinc oxide for optoelectronic applicationEwelina Nowak, Mirosław Szybowicz, Alicja Stachowiak, Detlev SchulzPoznań University of Technology Spectroscopy, semiconductors Abstract Wide bandgap semiconductors (WBGS) find more and more interest among research groups and main centers of the electronics industry. WBGS were originally tested and created for optoelectronics applications (due to shorter visible wavelengths, near ultraviolet), although nowadays their applicable potential is well-known. Due to high breakdown voltage, WBGSs are characterized by low resistivity and the possibility of using thinner layers, therefore they can be used in transistors in power devices. Most of WBGSs have the ability to create the so-called two-dimensional electron gas in heterostructures – what makes them work well in HEMT transistors. One of such material is zinc oxide (ZnO). ZnO is a II–VI compound semiconductor with a wide direct bandgap (3.37 eV at room temperature) and large excitation binding energy (around 60 meV). It has high electron concentration; however its electrical properties can be easily modified by controlling of defects or by doping. The most popular way to achieve material for electronic purposes is growing of thin layer. In most cases, thin layers of ZnO crystallize to zinc blend or wurtzite structure from amorphous film in high temperature. Although, to achieve high quality of doped thin film of ZnO is to use homoepitaxial growth on single bulk crystal. The final quality of the film will depend on the quality of the wafers used as substrates, what motivates to evaluate the quality before processing. The main aim of the presentation is to show results of investigation of the quality of structure of ZnO wafer growth by the vertical Bridgman method. Besides of micrographs and XRD, the quality of crystal can be successfully determined using optical methods. Research focused mostly on Raman microscopy investigations in polarized and non-polarized light. Our purpose, besides of evaluation of crystal structure, was to observe localized vibrational modes connected with changes in structure, which can occur with growing of a thin layer process. For complementary information FTIR, UV-VIS absorption and photoluminescence measurements were conducted. Acknowledgements Presented work has been financed by the Ministry of Science & Higher Education in Poland in 2018 year under Project No 06/65/DSMK/0010 References [1] C. F. Klingshirn, “ZnO: Material, physics and applications,” ChemPhysChem, 8, 6, 782–803, 2007 [2] W. Anwand et al., “Characterization of microstructural defects in melt grown ZnO single crystals,” J. Appl. Phys., 109, 6, 1–9, 2011 [3] K. Irmscher et al., “Coloration of zinc oxide crystals originating from particle plasmons,” Phys. Status Solidi Curr. Top. Solid State Phys., 6, 12, 2658–2660, 2009 [4] S. Eisermann et al., “Characterization of ZnO crystals grown by the vertical Bridgman method,” Phys. Status Solidi Appl. Mater. Sci., 208, 1, 37–41, 2011 [5] D. Schulz et al., “Bridgman-grown zinc oxide single crystals,” J. Cryst. Growth, 296, 1, 27–30, 2006. | |
| 10:15 | Artemis Tsimperi Radiodiagnostic devices in hospitals (thermo-luminescence dosimetry & TBI) | Gabriella Zsidi A multiwavelength view of highly accreting young stars in Taurus | Dewan Woods 2D Photonic Crystal Bandstructures | Nicolas Barón Pérez Development of silicon sensors for ATLAS upgrade | Tomáš Hrbek Magnetron sputtered thin films for proton exchange membrane water electrolysis |
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Radiodiagnostic devices in hospitals (thermo-luminescence dosimetry & TBI)Artemis TsimperiAristotle University of Thessaloniki Medical Physics Abstract Do you know what a physicist does in the hospital? Have you ever thought of helping people? Well i have spent 6 months doing my practise as a physicist in a hospital and here is a part of my work. Τhermoluminescent dosimeter, TLD are used in radiotherapy to diagnose the dose absorbed by the body.Αs a whole-body irradiation, TBI is defined the technique in which the patient receives almost uniformly throughout his body a specific radiation dose coming from external sources, a line of photonic linear accelerators. So how TLD and TBI connected? |
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A multiwavelength view of highly accreting young stars in TaurusGabriella ZsidiEötvös Loránd University Astrophysics Abstract Young stellar objects are in the early stage of their evolution, when they are still surrounded by a circumstellar disk made of gas and dust. Mass accretion from the circumstellar disk onto the star is a fundamental process in the formation of Sun-like stars. Accretion is inherently time variable, and its fluctuations are responsible for a significant fraction of photometric variations observed in young stars. However, other physical processes, such as rotating cold spots or the transit of a dust cloud can also change the observed brightness of the star. Since the wavelength dependence of the variability carries information on the physical cause of the changing brightness, it is necessary to observe these objects at different wavelengths. Here, we examined highly accreting young stars in Taurus, which were selected from the Campaign 13 field of the Kepler K2 mission. We complemented the K2 light curves by nightly multi-filter optical monitoring observations made with the 90 cm Schmidt telescope of Konkoly Observatory. In order to extend our wavelength coverage, cadence, and temporal coverage, we complemented these data with 3.6 and 4.5 micrometer infrared photometry obtained with a nightly cadence with the Spitzer Space Telescope. We constructed K2, B, V, R, I, and infrared light curves and investigated the brightness and color variations of our targets, to establish the origin of the variability and separate the different physical effects. Beside analysing the general variability characteristics and patterns, the detailed K2 light curves allowed us to study the so-far little understood phenomena related to the accretion process, such as periodic accretion signal variations. |
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2D Photonic Crystal BandstructuresDewan J. WoodsPurdue University Quantum Photonics Abstract The understanding of the nature of light and matter interactions at the interface of novel and exotic materials such as Metamaterials (MMs), Topological Insulators(TIs), and photonic crystals are essential for the continued growth of condensed matter physics and quantum photonics. Much research effort is being made to engineer and have the ability to tune the optical parameters of such materials, which in turn will tailor their electromagnetic response and thus allow for a better understanding of light, giving rise to interesting optical phenomenon in the process. In this theory-based talk, 2D photonic bandstructure-engineering will be investigated. Time permitted, topological effects in these materials will also be examined. |
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Development of silicon sensors for ATLAS upgradeNicolas Barón PérezLudwig-Maximilians-Universität München Accelerator physics Abstract ATLAS is one of the four major experiments installed at the Large Hadron Collider (LHC) at CERN (European Organization for Nuclear Research). ATLAS explores a range of physics topics, with the primary focus of improving our understanding of the fundamental constituents of matter and which are the forces that govern their interactions. While all the observations until now agree with the Standard Model predictions, the experiment actively searches for extensions of the Model, involving for example higher dimensions, and for new particles that could be the candidates for dark matter. The LHC accelerator will be upgraded by 2025 to reach a much higher protons collision rate. Concurrently the Inner Tracking system will be completely replaced to cope with the expected higher particle density. This sub-detector measures the direction, the momentum and the charge of electrically charged particles that are produced when protons collide. In order to fulfil the tracking requirements, the Max Planck Institute for Physics group (MPP) in Munich, Germany, is developing special silicon sensors, as well as investigating new connection technologies between sensors and read-out chips. In this talk, the functionality of these new sensors will be described together with their development process. |
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Magnetron sputtered thin films for proton exchange membrane water electrolysisTomáš HrbekCharles University, Faculty of Mathematics and Physics Physic of surfaces Abstract Proton exchange membrane (PEM) water electrolysis (PEMWE) is getting more attention in recent years as a promising alternative in context of energy storage from renewable sources. However, due to high prices of noble metals which are used as anode and cathode catalyst (e.g platinum, iridium), this technology isn't wide commercialized. We present using thin layers as anode catalyst as a method to increase efficiency of PEMWE. | |
| 10:30 | Judit Börcsök DNA METHYLATION PATTERNS AND HUMAN AGEING | Jacqueline Catalano Observation of the Stellar Cluster Westerlund 1 | Emil Vyff Jørgensen Effective Field theory for interactions of Rydberg Polaritons | Anna Varsted Reconstructing secondary particles produced in heavyion collisions at the LHC | Ivana Rilak Dimensionality-driven orthorhombic MoTe2 at room temperature |
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DNA METHYLATION PATTERNS AND HUMAN AGEINGJudit Börcsök, István CsabaiEötvös Loránd University Medical Biophysics Abstract In mammals, epigenetic mechanisms are essential for normal development and maintenance of tissue-specific gene expression levels. It has been observed that epigenetic patterns change over the lifetime, suggesting that these changes may play an important part in the aging process. The epigenetic mark that has been mostly studied is DNA methylation, the presence of methyl groups at CpG dinucleotides. These dinucleotides are often located close to gene promoters and linked to gene regulation. It has been shown by numerous studies that certain CpG sites are highly associated with age enabling to accurately estimate the chronological age of tissues and cell types. In my poster, I would like to present a comparison of several regression models of aging and demonstrate their applicability to predict age. For building the models, I used methylation data sets of different human tissues measured by Illumina methylation platforms from TCGA and GEO databases. Selecting the best fit model and CpG sites highly associated with age may provide a better insight into the aging process and age-related diseases. judit.borcsok27@gmail.com |
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Observation of the Stellar Cluster Westerlund 1Jacky CatalanoFriedrich-Alexander-Universität Erlangen-Nürnberg Astroparticlephysics Abstract Observation of the Stellar Cluster Westerlund 1 J. CATALANO$^1$, L. Mohrmann$^1$, M. Sasaki$^1$, A. Specovius$^1$, C. van Eldik$^1$ $^1$ ECAP, Erlangen Centre for Astroparticle Physics, FAU, Erlangen The open stellar cluster Westerlund 1 was discovered in the early 1960's and is one of the most massive clusters in our Galaxy. Westerlund 1 is located in the Galactic plane and is $\sim$ five million years old. It contains $\sim$ 80-150 very massive (< 50\,M$_{\text{sun}}$) young stars. Gamma rays with energies of several TeVs were detected from Westerlund 1 as well as X-ray emission in the keV range. It is still not clear whether the gamma rays are dominantly produced by a population of non-thermal protons or electrons. We carry out a multi-wavelength study to determine the origin of the radiation from Westerlund 1 and its environment. |
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Effective Field theory for interactions of Rydberg PolaritonsEmil Vyff Jørgensen,University of Southern Denmark Quantum Optics Abstract Mapping the strong interaction between Rydberg excitations in ultracold atomic ensembles onto single photons enables the realization of optical nonlinearities which can modify light on the level of individual photons. This novel approach forms the basis of a growing Rydberg quantum optics toolbox, which already contains photonic logic building-blocks such as single-photon sources, switches, transistors, and conditional pi-phase shifts. For the theoretical treatment of this novel system, a quasi-particle approach introducing Rydberg polaritons, has proved effective to describe interactions of photons mediated by the medium. However, as the number of photons in the experiments is increased, the treatment of the fully quantized system become increasingly difficult. Established methods from quantum field theory turn our to be a possible solution. We describe interaction among few polaritons under a simple potential using a diagrammatic approach. |
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Reconstructing secondary particles produced in heavyion collisions at the LHCRebekka Totlandsdal Markov, Anna Lundbergh Varsted and Elloise Jensen Fangel-LloydKøbenhavns Universitet Experimental particle physics Abstract V 0 particles are a group of hadrons formed by a strange quark (or antiquark) in combination with other quarks. Such particles include K0 s mesons and Λ and ¯Λ baryons, among others. Due to the unstable nature of strange quarks V 0 particles have very short lifetimes, making them difficult to study. This project reconstructs these particles by examining a dataset of all possible collisions and decays within a timeframe. Constraints are applied to the data based on a set of quantities known about the desired particles. These quantities are the invariant mass, charge, lifetime, the distance of closest approach and the pointing angle between the V 0 particles and its daughters. Following this, three different methods are used to identify the quality of selection: Armenteros-Podolanski analysis, Time of Flight data, and Time Projection Chamber data. These find that the selection of K0 s is quite good, but less so for Λ and ¯Λ selection. In order to find a quantitative number of candidates despite the remaining background a combination of Gaussian, linear and polynomial fits are applied and integrated. The findings are that the sample is 0.627% K0 s, 0.0711% Λ and 0.285% ¯Λ. The quality of these fits is evaluated using a χ2 test, which finds that while the fits appear quite good visually, the χ2red is slightly larger than expected, suggesting that the fits can still be optimized. |
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Dimensionality-driven orthorhombic MoTe2 at room temperatureIvana RilakUniversity of Belgrade Faculty of Physics 2D Materials Abstract With the discovery of the graphene in 2005, it was obvious that some materials isolated in a very thin layer have different characteristics than the same materials in bulk. That discovery launched a whole wave of the new research of thin flakes of Van der Waals materials, and resulted with Nobel Prize to the scientists who initially discovered graphene. It is known that when we isolate a thin flake of some material, it can also become sensitive to oxidation, and in order to do measurements with such flakes, they need to be protected from the oxidation with a thin flake of another material that is not prone to oxidation. In this talk, the study of thin flakes of the MoTe2, protected from oxidation, with Raman spectroscopy and transport measurements will be discussed. In contrast to bulk crystals, which undergo a phase transition from monoclinic to the orthorhombic phase below 250K, our results show that in thin samples below 12nm, a single orthorhombic phase exists up to and beyond room temperature. This could be due to the effect of c-axis confinement, which lowers the energy of an out-of-plane hole band and stabilizes the orthorhombic structure. Our results suggest that Weyl nodes may be observed in thin MoTe2 at room temperature. The lecture is based on work I have done at Tsen Lab at Institute for Quantum Computing University of Waterloo, Canada, and resulted in the paper: Phys. Rev. B 97, 041410(R) (2018). | |
| 10:45 | Zuzanna Lewandowska Brain-Computer Interfaces | Sabrina Gronow A possible progenitor of a supernova Ia: an explosion of a sub-Chandrasekhar mass white dwarf | Piotr Gładysz Interaction of an asymmetric two-level quantum system with light | Asia Peszka The search for antimatter, current research findings and future perspectives | Eduard Nicolae Sirjita Thin film Shellac depositions for organic field-effect transistors |
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Brain-Computer InterfacesZuzanna LewandowskaUniversity of Warsaw Applications of physics in medicine Abstract Brain-computer interface (BCI) is a device which allows to communicate with a computer without use of any muscles, only by the mental activity. Although they are being developed since more than two decades, it is still a technology better known from science-fiction movies than from reality. Not only is it a dream of humanity – to connect a brain with a computer - but so far, it is the only chance for communication with disabled suffering from illnesses like, for example, a motor neurone disease. Among non-invasive BCIs the most popular are based on electroencephalography (EEG) which is a method of monitoring electrical activity of the brain from electrodes placed on the scalp surface. There are three different paradigms of EEG-based BCIs. First one uses event-related potentials called P300, second one is based on the steady-state evoked potentials and third focuses on a motor imagery. All of these paradigms use EEG signals but exploit different properties of brain waves. They also have different efficiency and ease of use. I would like to explain how they work and talk about their possible applications in medicine. |
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A possible progenitor of a supernova Ia: an explosion of a sub-Chandrasekhar mass white dwarfSabrina GronowUniversity of Heidelberg/ Heidelberg Institute for Theoretical Studies Astrophysics Abstract Supernovae are the main contributers of iron in our galaxy and influence the galactic chemical evolution. The moving mesh code AREPO [1] is used to simulate the double detonation of a sub-Chandrasekhar mass white dwarf as a possible progenitor of a type Ia supernova. It allows a parallel treatment of the hydrodynamics and a nuclear network. The white dwarf is set up to consist of a carbon and oxygen core with a helium shell. The simulation follows the evolution of the shock waves after a first detonation is artificially ignited in the shell. The explosion mechanism that results in the supernova explosion is investigated considering different initial conditions and resolutions in the Helium shell. The results allow a comparison to previous work (for example [2] and [3]). [1] V. Springel, Monthly Notices of the Royal Astronomical Society 401, 791–851 (2010) [2] M. Fink, et al., Astronomy & Astrophysics 514, A53 (2010) [3] S. A. Sim, et al., Monthly Notices of the Royal Astronomical Society 420, 3003-3016 (2012). |
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Interaction of an asymmetric two-level quantum system with lightPiotr GładyszInstitute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, quantum optics Abstract "The subject of this contribution are quantum systems with broken inversion symmetry subject to a strong driving laser field, which can be used as an optically tunable radiation source. A two-level quantum system characterized with inversion symmetry and coupled to a classical electromagnetic field undergoes Rabi oscillations where the population flips between the ground and excited levels. I will demonstrate how the dynamics is modified if a system of broken inversion symmetry is exploited instead [1]. Then, the eigenstates are characterized with a permanent electric dipole moment originating from the polarisation of charges, which plays a significant role of an additional dipole source of radiation. The frequency of this radiation corresponds to the Rabi frequency of population transfer between the eigenstates [2], and could reach the terahertz domain if the quantum system is driven by strong electromagnetic fields, e.g. at close vicinity of plasmonic nanostructures [3]. What is more, the emission frequency would be tunable with a knob, by changing the intensity of the driving field. I will discuss the effect in the density matrix formalism, taking into account various decoherence mechanisms, including spontaneous emission and collisional dephasing. Estimates of radiation intensity will be provided for experimentally feasible realistic systems, such as ensembles of asymmetric molecules. [1] O. V. Kibis, G.Ya. Slepyan, S.A. Maksimienko, A. Hoffman, Matter Coupling to Strong Electromagnetic Fields in Two-Level Quantum Systems with Broken Inversion Symmetry, Physical Review Letters, 2009. [2] P. Gładysz, Asymetryczny układ dwupoziomowy w oddziaływaniu ze światłem, bachelor's thesis, Toruń (2017). [3] L. Novotny, N. van Hulst, Antennas for light, Nature Photonics, 5, 83–90 (2011)." |
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The search for antimatter, current research findings and future perspectivesJoanna PeszkaWroclaw University of Science and Technology antimatter, atomic physics, plasma physics Abstract Since around 30 years experimental physicists have been trying to investigate antimatter and answear most fundamental questions about the universe. Is there any difference between normal matter and antimatter? What is the reason of matter over antimatter predominance? Antimatter Factory located at CERN already allows us to produce and investigated properties of antimatter and even produce simple antiatoms. Antiproton Decelerator (AD) facility provides a beam of antiprotons $\overline{p}$, which is combined with positrons e+ to produce antihydrogen atoms $\overline{H}$. Various features of antimatter are measured like electric charge and magnetic moment of antiparticles, $\overline{H}$ response to the light excitation etc. ALPHA Collaboration is studying spectrum of light produced by antyhydrogen atoms and comparing results with "normal" hydrogen's light response. Transition between first energy levels in antyhydrogen atom has been already observed and it is the most precise measurement of antimatter ever made. Next challenge for antimatter hunters is to improve accuracy of these results and to study another properties of antimatter like gravity intereaction. For this purpose new experiments are constructed right now at CERN and maybe soon we will be able to answer one of the most fundamental question - if the antimatter is attracted or repelled by normal matter? |
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Thin film Shellac depositions for organic field-effect transistorsEduard-Nicolae Sirjita, Andreea Matei, Simona Brajnicov, Bogdana Mitu, Adrian Bercea, Valentina MarascuFaculty of Physics,University of Bucharest Optics Abstract Shellac is a very interesting material that has been used since antiquity because of its unique properties for which new applications can be found even in modern times. Shellac, a natural biopolymer, is a the purified product of the natural material lac which is secreted by the small parasitic insect Kerria Lacca that can be found on certain trees in the south east of Asia, in countries such as India or Thailand. Based on the refining process of the initial secretion of the bug, the final shellac can have different properties with different applications. In this study we have investigated the dielectric properties of thin films of shellac which has been deposited using the MAPLE technique. The purpose is to integrate shellac into future organic field-effect transistors with various use and throw applications. The results are promising and show that shellac thin films have a high dielectric constant and could be a promising material for future applications. | |
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| 11:15 | Sascha Ranftl A physicist acts as physician: How Bayesian inference might save lives through the foresighted prediction of aortic dissection. | Giorgi Khomeriki The motion and emission analysis of relativistic gas of charged particles in the rotating pulsar magnetosphere | Gerard Valentí-Rojas How to Create a Universe in the Lab | Magdalena Kołodziej Construction and optimization of scintillator-based particle detectors for the BRAND project | Noah Hardwicke Monte-Carlo Simulation of a p-n Junction Diode |
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A physicist acts as physician: How Bayesian inference might save lives through the foresighted prediction of aortic dissection.Sascha RanftlUniversity of Technology Graz, Centre of Computational Engineering, Institute of Theoretical Physics Bayesian probability theory, humane medicine, biomedical engineering, biophysics, biomechanics, fluid dynamics, hemo dynamics Abstract Aortic dissection (AD) is a defect of the aortic wall tissue with life-threatening consequential damage. The goal of the project is to develop computational tools and advanced algorithms, to simulate cardiovascular mechanics, and based on noninvasive medical images and novel data analysis techniques, to quantify patient-specific anatomical and fluid-structure interaction models for AD. The computational framework will be capable of investigating wall stresses, the hemodynamics, false lumen propagation, exchange of blood between true and false lumina, thrombus formation and growth, at any stage of the disease. This will help to better understand the mechanobiological event and to finally assist clinicians with the diagnosis, treatment and management of AD patients. |
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The motion and emission analysis of relativistic gas of charged particles in the rotating pulsar magnetosphereg.khomeriki, AD Rogava, GZ MachabeliTbilisi State University Astrophysics, particle physics. Abstract Firstly, the motion of one particle alongside pulsar magnetic field lines is considered. We find another solution for already well-known equation of motion of this system. In reality, magnetic field is not able to hold high-energy particles, and thus we consider this case and compute the motion of gas of particles in Matlab. We find the signal that the gas of particles emits from pulsar light cylinder. After this, we analyze in which conditions one will distinguish given signal and how will it disfigure Pulsar's periodic pulses. The result is that by our model we can explain newly detected Tera Electronvolt signals from pulsars. This paper is not published yet. However, I have one publication in Physics Letters A https://www.sciencedirect.com/science/article/pii/S0375960116302717. |
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How to Create a Universe in the LabGerard Valentí-RojasICFO Quantum Simulation / Ultracold Atoms / Quantum Field Theory / General Relativity Abstract The laws of quantum mechanics have helped scientists to unravel the behaviour of nature at its most fundamental scales. However, quantum phenomena are often difficult to understand and simulations have historically provided a useful framework for their study. Nevertheless, when dealing with large quantum systems or real-time dynamics, the computational cost of numerical simulations can become unfeasible. A proposal to face this problem is the notion of a quantum simulator, a controllable device governed itself by the laws of quantum mechanics that allows to replicate the conditions of a physical system or process. An intriguing application of quantum simulators is the study of the dynamics of particles in curved gravitational backgrounds. Our research is aimed to gain some insight into how Dirac fermions behave in an homogeneous, isotropic and expanding (2+1)-d universe. The implementation of such a system using ultracold atoms in an optical lattice could lead to the observation of exotic effects such as a particle horizon or the cosmological creation of particles. This could pave the way for a novel approach to problems typically restricted to high energy particle physics or cosmology. |
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Construction and optimization of scintillator-based particle detectors for the BRAND projectMagdalena KołodziejJagiellonian University in Cracow Experimental nuclear physics Abstract As the Standard Model (SM) has certain inconsistencies, a lot of effort is being put on a search for physics beyond it. One of the experiments in this context is the BRAND project being conducted in Jagiellonian University in Cracow that concentrates on analyzing properties of neutrons. The aim is to measure eleven correlation coefficients of neutron decay, some of which have never been measured before, and look for small deviations which may indicate exotic interactions not predicted by the SM. To do this, an experimental setup of cylindrical geometry will be constructed. Particle detectors will be placed along the cylinder, around the source of neutron decay. One of the questions here is how to measure an exact position of a particle along the cylinder axis. To address this problem, a prototype of a scintillation detector has been constructed and particle detection methods that give the best possible position resolution at a minimal cost are studied. A search for the optimal detector prototype will be presented. |
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Monte-Carlo Simulation of a p-n Junction DiodeNoah HardwickeUniversity of Nottingham Semiconductor Physics, Computational Physics Abstract Presented is a monte-carlo simulation of holes and electrons moving inside a p-n junction diode under zero-, forward- and reverse-bias conditions. The program simulates the exponential I-V characteristic of an ideal diode. Electron transport processes inside a semiconductor are discussed to justify the use of an n-body model for carrier dynamics, and a brief walkthrough of the code, written in Mathematica, shows how the simulation supports acceptable frame rates and may be used for illustrative and educational purposes. | |
| 11:30 | Diego Fernández Prado Magnetic Nanostructures as Multimodal Contrast Agents with Biomedical Activity | Giorgi Bakhtadze Centrifugal acceleration in the isotropic photon field | Christoph Dauer Controll of Scattering by Time-Periodic Driving | Samuel Borer Measuring the Cross Section of Charge Current Quasi-Elastic Neutral Hyperons in ArgoNeuT | Robert Rauter Molecular dynamics study of the vibrational properties of spin-crossover materials |
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Magnetic Nanostructures as Multimodal Contrast Agents with Biomedical ActivityDiego Fernández PradoUniversity of Santiago de Compostela Nanotechnology Abstract Magnetic nanostructures based on iron oxides with biocompatible layers can be used in biomedicine as probes or theranostic agents (for example to diagnose cancer). The present work examines its possible application as multimodal contrast agents in medical imaging as well as its theranostic functionalities. |
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Centrifugal acceleration in the isotropic photon fieldGiorgi BakhtadzeFree University of Tbilisi Astrophysics Abstract In my lecture I will discuss about centrifugal acceleration of particles moving along a prescribed rotating curved trajectories. We consider the physical system embedded in an isotropic photon field and study the influence of the photon drag force on the acceleration process. For this purpose we study three major configurations of the field lines: the straight line; the Archimede’s spiral and the dipolar field line configuration. By analysing dynamics of particles sliding along the field lines in the equatorial plane we have found several interesting features of motion. In particular, it has been shown that for rectilinear field lines the particles reach the light cylinder (area where the linear velocity of rotation exactly equals the speed of light) zone relatively slowly for bigger drag forces. Considering the Archimede’s spiral, we have found that in cases when the field lines lag behind the rotation, the particles achieve the force-free regime of dynamics regardless of the drag force. Unlike this scenario, when the spiral is screwed up in an opposite direction there the particles do not reach the force free regime, but tend to stable equilibrium locations. |
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Controll of Scattering by Time-Periodic DrivingChristoph DauerTU Kaiserslautern Quantum Physics Abstract Ultracold quantum gases are a large experimental playground, as they are controllable in a wide manner. This presentation discusses the tuning of the interaction strength of particles with a time-dependent interaction potential. It reveals that there are resonances, which allow a large enhancement of scattering of particles by this time-dependent interaction. These resonances can be explained by Fano interference and be used to tune the interaction strength in a quantum gas experiment. |
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Measuring the Cross Section of Charge Current Quasi-Elastic Neutral Hyperons in ArgoNeuTSamuel BorerUniversity of Maine Particle Physics Abstract This presentation will cover work done on the first topological and calorimetric study of the cross section measurement of antineutrino-induced charge current quasi-elastic (CCQE) neutral hyperons in liquid argon. This study is being conducted in the Argon Neutrino Test (ArgoNeuT) experiment at Fermi National Accelerator Laboratory. ArgoNeuT is a liquid argon time projection chamber (LArTPC), which provides full 3D-imaging, excellent particle identification capability, precise calorimetric energy reconstruction, and represents the most advanced experimental technology for neutrino physics. This project uses 1.2x10^20 protons-on-target, in the NuMI beam operating in the low energy antineutrino mode. The reconstruction and analysis techniques developed and improved in this study can be applied to a wide variety of future LArTPC experiments. CCQE Neutral Hyperons are induced exclusively by antineutrinos and can be used as an “antineutrino tagger” for larger experiments. This presentation will present analysis techniques and preliminary findings for the CCQE neutral hyperon cross-section in liquid argon. |
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Molecular dynamics study of the vibrational properties of spin-crossover materialsRobert Rauter, Christian Mücksch, Herbert M. UrbassekTechnische Universität Kaiserslautern Computational Physics Abstract Spin-crossover materials exhibit the unique ability to switch between a low-spin and a high-spin state, indicating their potential as possible organic storage devices. A switch between the low and the high spin state is reflected by a frequency shift in the phonon density of states. This makes the phonon density of states an interesting tool to analyze spin-crossover materials. The calculation of crystal or molecular nanostructures built of spin-crossover materials exceeds the limit of DFT calculations, due to the large number of atoms that need be considered. We use a molecular dynamics approach to calculate the phonon density of states for both spin states. The force constants required for the simulation are provided by DFT calculations. The phonon density of states is then determined by calculating the Fourier-transform of the velocity autocorrelation function. We report on the progress of the molecular dynamics simulations of spin crossover materials, particularly focusing on the calculation of the phonon density of states. The calculated phonon density of states is compared to experimental nuclear-inelastic scattering spectra and results from DFT calculations. | |
| 11:45 | Alexandre Coates Quantum Effects in Biology - How, Why and What About Noise? | Hannah Dalgleish Integral field unit spectroscopy and nearby globular clusters | Sonja Gombar Quantum entanglement and quantum coherence of an XY spin chain with Dzyaloshinskii-Moriya interaction | Beatrice Mauri Noise characterization of Transition Edge Sensors cryogenic microcalorimeters for the neutrino mass measurement | James Kneller The story of a PhD in Organic Electronics - The building of a Radio Lens |
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Quantum Effects in Biology - How, Why and What About Noise?Alexandre CoatesUniversity of Birmingham Quantum Biology Abstract In recent years due to rising interest and the development of ultra short pulse spectroscopy it has become possible to probe more directly into the existence of Quantum Mechanical effects in 'warm, wet' biological systems. Currently, observation support the idea that quantum effects are used in a variety of processes, notably in harvesting light within photosynthesis and sight, and again in transferring the energy with near-100% efficiency, again for photosynthesis. This talk aims to give a little overview of how this is possible in the wild and noisy internal world of plants and animals, and discuss a little about future research within this new and growing field. |
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Integral field unit spectroscopy and nearby globular clustersHannah DalgleishLiverpool John Moores University Astrophysics: Stellar Clusters Abstract WAGGS, the WiFeS Atlas of Galactic Globular cluster Spectra, is a library of integral-field spectra addressing a wide range of questions currently posed by the field. The central regions of 84 Milky Way globular clusters (GCs) have been observed, in addition to 30 GCs of the Galaxy’s low-mass satellites. The data spans the widest range of metallicities, ages, and masses compared to any other dataset to date. Because globular clusters are isolated and formed at roughly the same time in the same environment, GCs are excellent laboratories for studying stellar evolution as well as the history of our own galaxy. With the WAGGS data we can examine trends in rotation or study the mass-to-light ratio as a function of metallicity for example. The latter has a major influence on our understanding of old stellar populations, which is essential since this affects mass estimates of elliptical galaxies. |
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Quantum entanglement and quantum coherence of an XY spin chain with Dzyaloshinskii-Moriya interactionSonja GombarUniversity of Novi Sad Theoretical Physics Abstract Recently, there has been an increased interest in studying quantum entanglement and quantum coherence. Since both of these properties are attributed to the existence of quantum superposition, it would be useful to determine if some type of correlation between them exists. Hence, the purpose of this talk will be to explore the type of the correlation in several systems with different types of anisotropy. The focus will be on the XY spin chains with the Dzyaloshinskii-Moriya interaction and the type of the mentioned bond will be explored using the quantum renormalization group method. Both quantum coherence and quantum entanglement were explored as the quantities that can indicate the existence of the quantum phase transitions and thus one can see how different types of anisotropy in these systems affect its appearance. |
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Noise characterization of Transition Edge Sensors cryogenic microcalorimeters for the neutrino mass measurementMauri BeatriceUniversità degli Studi di Milano-Bicocca Particle Physics Abstract The purpose of this lecture is the noise characterization of the first transition edge cryogenic microcalorimeters prototypes (TES) used in the HOLMES experiment. The aim of HOLMES is to perform the direct measurement of the neutrino mass by studying the end-point of the holmium-163 electron capture spectrum. This isotope is chosen because of its very high specific activity, that allows the possibility of implanting nuclei in the absorbers made of different materials, and because of the statistical increase due to the small energetic difference between the M1 shell and the Q-value. In the final configuration HOLMES will achieve a final neutrino mass sensitivity as low as as 2 eV by deploying 1000 detectors, with a total activity of 300 Bq of 163Ho per pixel. TESs are superconducting detectors able to convert the energy deposited into an absorber in a resistance variation of the superconducting film. Since the very low detector impedances, it is not possible to use traditional amplification techniques so the resistence variations are amplified by employing extremely sensitive magnetometers known as SQUIDs (Superconducting Quantum Interface Device). HOLMES uses rf-SQUIDs to convert an electrical current changes into the TESs in a flux variation. This variation induces a resonance frequency shift in a microrisonator circuit inductively coupled to the SQUID. By tuning the microresonators resonant frequencies at different values, it is possible to monitor the status of different TESs by using the same feedline, implementing a multiplexing technique called microwave multiplexing. This technique provides a bandwidth compatible to time resolution needed for HOLMES without worsening the energetic resolution and the intrinsic noise. In my thesis work, I used the microwave multiplexing to characterize the electronic noise of the first detectors prototypes specifically developed for HOLMES. Noise analysis and understanding are an important part of the detectors characterization because noise sources can limit the detectors energetic resolution and performances. Experimentally, noise is acquired by selecting signals without events due to interaction; these are then converted in power spectrum by using Fourier analysis. To obtain a complete characterization, necessary to extract the different noise sources contributions, measurements have been performed with a base temperature ranging between 30 mK and 160 mK with steps of 10 mK and with two different current biases: unbiased and at 20% of normal resistance. Moreover, for some fixed temperatures, measurements have been performed with voltage biases in the range from 0% to 100% of the normal resistance. The estimation of the noise parameters have been performed as a function of the temperature and of the polarization bias. Results have been compared with the theoretical parameters provided by the theoretical model. |
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The story of a PhD in Organic Electronics - The building of a Radio LensJames KnellerQueen Mary, University of London Condenced Matter and Material Physics, Being cute Abstract This talk will overview the journey of completing a PhD in the field or Organic Electronics. From the fabrication of, experiments on and science behind, the plastic based solar cells and antennas I research. Questions I will be answering will include “What’s a HOMO?” (Highest Order Molecular Orbital), “What equipment gives the most electric shocks” and “What’s the key to finishing a PhD on Time”. The End game of this research is to create an optically controlled dynamic lens for radio waves/terahertz applications, which I will give a account of the physics and the processes towards achieving this. |
| A: Biophysics and chemical physics | B: Astrophysics | C: Theoretical physics / QFT | D: Particle physics | E: Materials physics | |
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| Hall 6 | Hall 7 | Hall 8 | Hall 10 | Hall 12 | |
| 16:00 | Monika Schied Molecular motors on Cu(111) studied by scanning tunneling microscopy | Enrico Catalano Astrobiology and Astrobiotechnology: the state of the art and its future evolution | Dominik Gerstung Hyperon single-particle and chemical potentials in nuclear matter from SU(3) chiral effective field theory | Oliver Lantwin How to find new particles we don't know anything about | Sofia Ferreira Teixeira Bi-Te and Sb-Te Topological Insulator Materials: from first principle calculations towards nanostructures fabircation |
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Molecular motors on Cu(111) studied by scanning tunneling microscopyMonika Schied (1), Peter Jacobson (1), Dongdong Liu (2), James M. Tour (2), and Leonhard Grill (1)Karl-Franzens-Universität Single molecule chemistry Abstract Artificial molecular motors can translate an external stimulus into controlled motion. They have seen great developments in the last decades [1]. While many studies exist in solution, only very little is known how such functional molecules behave on a surface, although such a setup holds the advantage of a fixed point of reference. This is of importance for a key property of molecular machines, the directionality of their motion in a static environment. In this study, artificial motor molecules have been investigated, all based on a combination of double bond isomerization and helix inversion, which are the key processes responsible for rotation of the so-called Feringa motor. This type of motor has already been used to successfully drive lateral translation of molecules at surfaces [2, 3]. Experiments were done by low temperature scanning tunneling microscopy (STM) to enable imaging of one and the same molecule before applying an external stimulus. The focus of our study is on the adsorption of such molecules at metallic surfaces and what type of motion can be induced by either STM manipulation or illumination by light. [1] W. R. Browne and B. L. Feringa, Nat. Nanotech. 1, 25 (2006) [2] T. Kudernac et al., Nature 479, 208 (2011) [3] A. Saywell et al., ACS Nano 10, 10945 (2016). |
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Astrobiology and Astrobiotechnology: the state of the art and its future evolutionCatalano EnricoUniversity of Milano-Bicocca Astrobiology, Astrophysics, Astronomy Abstract Astrobiology is a broad research domain that encompasses wide areas of the scientific landscape. Astrobiology is a very interdisciplinary field that traverses a very wide spectrum of spatial and temporal scales: from prebiotic chemistry to geomicrobiology, atmospheric sciences, and astronomy. This maturing field cuts across many scientific concepts ranging from the molecular level to ecosystems and planetary systems, at scales ranging from Earth’s (sub)surface to planetary objects detected thousands of light years away. Several hypotheses have been proposed to explain life in the cosmic context throughout all the human history, but only now, science&technology has allowed many of them to be tested. Astrobiotechnology can be intended as the evolution of astrobiology and exobiology for understanding the origins of life to its future evolution and destiny on Earth and exoplanets. Astrobiotechnology can further implement the field of astrobiology through the integration with other fields like biotechnology, complex systems in biology, synthetic biology, astrophysics, systems biology, etc. It can be also used for understanding accurately how biochemistry of life on Earth has been evolved and how alternative exotic forms of life based on carbon or alternative chemical elements such as silicon and nitrogen can be feasible. In the last years several exoplanets were detected so far by missions like Kepler or the even temperate several terrestrial planets of the ultra-cool red dwarf star TRAPPIST-1 with Trappist-1d and Trappist-1e, that could be potentially habitable. The conditions suitable for life could be also present on the moons of Saturn: Europe and Titan, and Ganymede the moon of Jupiter. Another branch of astrobiology is looking for searching life on Mars that had earth-like conditions over 3.5-4 billion years ago with the presence of rivers and lakes and so possible conditions suitable for triggering the origin of life. This work is a brief review of the state of the art of the astrobiology and its possible evolutions in order to identify alien life forms on other planets and potential habitable exoplanets useful for human space colonization. |
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Hyperon single-particle and chemical potentials in nuclear matter from SU(3) chiral effective field theoryDominik GerstungTU München Quantum Field Theory Abstract Brueckner theory is employed to calculate the single-particle potentials of nucleons and hyperons in nuclear matter. The underlying twobody interactions consist of the next-to-leading order chiral two-baryon potentials and effective density-dependent baryon-baryon interactions derived from the leading order chiral three-baryon forces. We compute the chemical potentials of neutrons and Λ(1116)-hyperons from the energy density of strongly interacting baryonic matter. The implications for the possible occurrence of strange baryons in neutron-star matter are discussed. Work supported in part by DFG and NSFC (CRC110). |
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How to find new particles we don't know anything aboutOliver LantwinImperial College London High Energy Physics Abstract We know there is new physics: we can see it everywhere we look in the universe! Gravity, dark matter, the expansion of the universe and our very existence prove that there is more to discover in fundamental physics. However, we know next to nothing about this new physics! Nonetheless, I'll discuss how one can, using our knowledge of the standard model, construct an experiment to cover a huge range of possible models independent of theoretical fashions. |
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Bi-Te and Sb-Te Topological Insulator Materials: from first principle calculations towards nanostructures fabircationSofia Ferreira Teixeira, Ana Lúcia Pires, André PereiraUniversity of Porto / Imperial College London Condensed Matter Physics / Material Physics / Nanotechnology Abstract Topological Insulators (TI) are a recently discovered category of materials. They host a protected metallic state on their surface while having an insulating bulk. This state appears in the form of a spin-textured Dirac cone, with spin locked with momentum [1]. A wide range of applications are foreseen to exist for TI materials [2]. However, more studies, experimental realisation of the TI materials and tuning of the TI state must be accomplished using scalable and industrialised fabrication techniques, prior to their wide usage. The focus of this work was the growth of TI thin films based on Sb-Te and Bi-Te by Ion Beam Sputtering Deposition (IBD), a top-down technique used in the industry [3]. Moreover, an insight into the thin films' behaviour was also made through First Principle Calculations [4]. The Sb-Te and Bi-Te thin films were sputtered with thicknesses ranging from few nanometers to hundreds of nanometers. The impact of the IBD parameters on the morphology,stoichiometry and structure of the thin films was studied [5]. Furthermore, their influence on the thin film transport and magnetotransport properties was characterised. Resistivity and thermopower were measured as a function of temperature and the magnetoresistance for high magnetic fields was also obtained. DFT calculations of bulk and thin films Sb2Te3 and Bi2Te3 were also performed using the WIEN2K software package. The transport properties of the several structures were calculated based on the WIEN2K outputs, using Boltzmann Transport Theory in the BoltzTraP code. The results give insight into the behaviour of the sputtered thin films. In this presentation, the influence of the IBD parameters on the properties of the topological insulators sputtered thin films will be presented. An overview of how the DFT calculations can be used to explain and study the behaviour of the sputtered thin films is also shown. [1] Hasan, M. Z., Kane, C. L. (2010). Reviews of Modern Physics, 82(4), 3045.; [2] Pesin, D., MacDonald, A. H. (2012). Nature materials, 11(5), 409.; [3] Fan, P., Zheng, Z. H., Liang, G. X., Zhang, D. P., Cai, X. M. (2010). Journal of Alloys and Compounds, 505(1), 278-280.; [4] Li, Z., Miao, N., Zhou, J., Sun, Z., Liu, Z., Xu, H. (2018). Nano Energy, 43, 285-290.; [5] Pires, A. L., Cruz, I. F., Ferreira-Teixeira, S., Resende, P. M., Pereira, A. M. (2017). Materials Today: Proceedings, 4(12), 12383-12390. | |
| 16:15 | Yvonne Zagzag Monitoring the Kinetics Of Molecular Binding using Holographic Video Microscopy | Domenico Tiziani A new analysis method for Very High Energy Gamma-ray astronomy | Matteo Broccoli On the trace anomaly of a Weyl fermion | Balázs Endre Szigeti Angular Correlations in AMPT | Nils Sommer Current driven domain wall creation in chiral magnetic nanowires |
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Monitoring the Kinetics Of Molecular Binding using Holographic Video MicroscopyDavid Grier, Mark Hannel, Yvonne ZagzagNew York University Soft Matter Physics & Optics Abstract My project will determine the extent to which a Holographic Video Microscopy (HVM), can reveal the kinetics of molecular binding. In this experiment I will use HVM to measure how the radii of micrometer-scale beads increase as molecules bind to their surfaces. We watch these spheres grow as particles bind to the sphere's surface. If able to do so, this will be revolutionary in the study of molecular binding, and general particle observation. I will outfit my own holographic microscope with an environmentally controlled chamber in which I can incubate individual particles and watch the binding process in situ. |
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A new analysis method for Very High Energy Gamma-ray astronomyDomenico Tiziani, Christopher van Eldik, Stefan Funk, Lars Mohrmann, Christopher Sobel, Andreas SpecoviusFriedrich-Alexander University Erlangen-Nuremberg Astroparticle Physics / Gamma-ray Astronomy Abstract In the field of very-high-energy gamma-ray astronomy, data taken by the individual experiments are typically analysed with tools that are solely available to the respective collaborations. An important aspect of these analysis tools is the estimation of background due to contamination by cosmic rays in the data. To achieve this, most of these tools make use of skyregions that are free of gamma-ray sources but reside in the same field-of-view as the analysed source. For more complex sources and regions in the sky which are crowded by sources, these background estimation techniques may not be easily applicable. In these cases, a template analysis approach, in which the spectral and morphological characteristics of both the sources of interest and the background are modelled, might be superior. Furthermore, the upcoming Cherenkov Telescope Array (CTA), which will release its taken data to the public, necessitates analysis tools that are available to the whole astronomical community. In this talk, the application of open source analysis tools to experimental data from the H.E.S.S. public data release is presented. It is shown how template analyses of gamma-ray sources can be carried out that make use of a generic background model. The latter is derived from observations of source-free regions performed under similar conditions as the observations of the analysed sources. |
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On the trace anomaly of a Weyl fermionMatteo BroccoliAlma Mater Studiorum Quantum field theory, conformal field theory Abstract We will present recent computations of the chiral and trace anomalies of a Weyl fermion coupled to a U(1) abelian background gauge and then to a more general SU(N) non abelian background gauge. In particular, we are interested in the possible presence in the anomalies of a term proportional to the Pontryagin density, on which there has recently been some controversy. Our computations, carried out with the Fujikawa method and a Pauli-Villars regularization, should show whether this term is indeed present or not and should shed new light on this issue. |
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Angular Correlations in AMPTBalázs Endre SzigetiEötvös Loránd University Heavy-Ion Physics Abstract The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a wide $p_T$ region inaccessible by direct jet identification. In these measurements pseudorapidity ($\Delta \eta$) and azimuthal ($\Delta \varphi$) differences are used to extract the shape of the near-side peak formed by particles associated to a higher pT trigger particle. I used AMPT (A MultiPhase Transport) model to simulate heavy-ion collision in 2760 GeV and I used identified two-particle correlations to study jet-shape. |
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Current driven domain wall creation in chiral magnetic nanowiresNils Sommer, Davi R. Rodrigues, Karin Everschor-SitteJohannes Gutenberg-Universität Mainz Solid state physics, magnetism Abstract A central topic in spintronics is the manipulation of magnetic textures by currents. In a recent work, it was predicted that magnetic domain walls can be generated in ferromagnetic nanowires by means of an electric current once there is an inhomogeneity. [1] In this work, the focus was on a set-up where i) no twisting like interaction was taken into account and ii) the magnetization of the ferromagnetic wire was mainly aligned along the wire. Only the magnetization at one end of the wire was fixed along a perpendicular direction. In our work we analyze the influence of an interaction which induces twists as well as the influence of the orientation of the fixed magnetization to the strength of the critical current above which domain walls are shedded. We show that while reducing the tilting angle of the fixed magnetization the strength of the critical current is increasing. Including the twisting interaction, called Dzyaloshinskii-Moriya Interaction (DMI) we find that with increasing DMI strength the critical current is decreasing. [1]Sitte, M. et al., Physical Review B 94 (2016) 064422. | |
| 16:30 | Rene Hamburger Water purification with molecular simulations | Ágnes Kis-Tóth Cosmological Ionized Bubbles | Chiara Signorile-Signorile Infrared divergences in Perturbative QCD | David Katona Numerical Simulation of Axionic Strings | Alejandro Fernández Muñoz Grandma's recipes: UCM nanowires |
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Water purification with molecular simulationsRené Hamburger (1,2)TUK/ Fraunhofer ITWM Molecular mechanics Abstract Our ground and drinking water is more and more polluted by pharmaceuticals whilst up to now many of them have neither been monitored nor filtered out in the recycling process of a purification plant. In order to tackle this problem, we’ll test specific filter materials for certain pharmaceuticals on an atomistic scale with molecular dynamics simulation. We obtain a free energy profile of the interaction by the so-called adaptive biasing force method to further model the dynamics on a mesoscopic level. |
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Cosmological Ionized BubblesÁgnes Kis-TóthEötvös Loránd University Astrophysics Abstract -The epoch of cosmological reionization, around z~6, and the nature of the ionizing sources bear fundamental cosmological importance, but are yet unknown. Our knowledge of the classical H II regions around hot stars suggests how this process might have happened. Ionizing sources, whether galaxies or quasars or sources of other nature, embedded in the neutral intergalactic medium (IGM) before cosmological reionization generated separate H II regions, and these regions eventually could have overlapped to ionize the whole universe. We derive the cosmological generalization of the classical Strömgren sphere to the case of a quasar as an ionizing source in a comologically expanding gas in a Friedmann-Robertson-Walker universe. Such ionized regions in the closer universe, around z~3-4, were recetly discovered with the MUSE telescope and in the future we might will be able to measure similar bubbles before cosmological reionization as well using the JWST telescope. |
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Infrared divergences in Perturbative QCDChiara Signorile-SignorileUniversità degli Studi di Torino Perturbative QCD Abstract The presentation concerns the Perturbative QCD approach to hadronic scattering, with a particular attention to the study of infrared and collinear singularities in the corresponding amplitudes. At cross-section level these singularities cancel, leaving logarithmic contribution in the threshold variable that can spoil the perturbative expansion. In this work we analyse the functions that allow a full factorisation of simple amplitudes, trying to generalise their operator definition to model a gluon- induced jet. |
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Numerical Simulation of Axionic StringsDavid KatonaEötvös Loránd University Particle physics Abstract Axion is a hypothesised particle that could solve two basic problems in physics. Originally it was postulated as a solution for the strong CP problem, but it is an ideal candidate for dark matter as well. In order to experimentally detect axions it is crucial to give a numerical approximation of its mass, which can be calculated if we assume that all the dark matter is made up of axions and we determine the number of axions with simulations. Axion can be introduced as the phase of a complex scalar field which has non-zero vacuum expectation value. Because of its spontaneous symmetry-breaking potential one dimensional topological defects, strings can form. These strings make numerical simulations much harder because of the many orders of magnitude difference between the size of string cores and the typical distance of two strings. In my work I simulate the time development of string networks in the early expanding universe. |
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Grandma's recipes: UCM nanowiresAlejandro Fernández MuñozComplutense University of Madrid Nanophysics Abstract What better for cold Helsinki than a warm and tasty bowl of nanowires? In this lecture I will cover the several growing methods that researchers at Complutense University of Madrid use to produce these nanostructures, which application ranges from biomedical physics to quantum computers, giving a glimpse of the State of the Art of each method. Everything seasoned, of course, with the actual materials and test pieces which we use in the lab, so that everyone can touch what we make, and as most laughter as possible. | |
| 16:45 | Marianela Quiros Rojas Toy model for the structural study of different galaxy redshifts | Rebecca Jolitz Predicting aurora at Mars using observations from the MAVEN spacecraft | Adrian Solymos Anyons and the mathematics behind them | Bálint Kurgyis Three dimensional Bose-Einstein correlations in heavy-ion collisions | Valerio Peri Axial field induced chiral channels in acoustic Weyl system |
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Toy model for the structural study of different galaxy redshiftsMarianela Quiros-Rojas(1), Itziar Aretxaga(2), Alfredo Montaña(2).University of Costa Rica Astrophysics Abstract Galaxies are the fundamental structure that allows us to study the evolution of the Universe. The formation and evolution of galaxies is one of the most active research topics in contemporary astrophysics. In the distant Universe, galaxies are forming. The structure of a spiral galaxy was built: bulb, disk and stellar regions, through the use of the Python programming language. This galaxy comprises an extension of 20 kpc of radius, based on the spiral galaxy M81. For the distribution of surface brightness, the Law of De Vaucouleurs for the bulb and the Exponential Law for the disk were used, in addition to optical and infrared spectra of spiral galaxies for the disk, elliptical for the bulb and irregular for the regions of star formation to extrapolate the emission of the different regions of the galaxy emission from $ z \approx 0.25 $ to $ z \approx 2 $. With this it was possible to study the evolution process, as well as the decrease in angular size of the galaxy to higher redshifts. The appearance of the galactic structure is highly affected by shifts greater than $ z \approx 0.25 $, which makes it difficult to study these regions at infrared wavelengths or greater. |
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Predicting aurora at Mars using observations from the MAVEN spacecraftR. D. Jolitz, C. F. Dong, C. O. Lee, R. J. Lillis, D. A. Brain, S. M. Curry, D. E. Larson, S. Bougher, B. M. JakoskyUniversity of Colorado, Boulder Space physics Abstract During periods of intense solar activity, solar energetic particles (SEPs) can precipitate into planetary atmospheres and excite the neutral gases, causing aurora. While Earth has an intrinsic magnetic field that confines particle precipitation to the poles, SEPs at Mars are guided by draped magnetic fields from the global induced magnetosphere and intensely magnetized crustal anomalies localized in the Southern hemisphere. Using fluxes measured by the SEP instrument onboard the Mars Atmosphere Volatile Evolution (MAVEN) orbiter, we simulate the transport of 100 keV SEP electrons in representative magnetic field configurations to predict possible zones of aurora. We present maps of SEP precipitation in draped magnetic fields, crustal anomalies, and the combination. We find that the combination of crustal anomalies and draped fields attenuate SEP precipitation in the Northern hemisphere and amplify SEP precipitation along the crustal anomalies in the Southern hemisphere. This suggests that SEP electrons could be linked to discrete aurora that have been detected by MAVEN and other Mars-orbiting spacecraft. |
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Anyons and the mathematics behind themAdrian SolymosEötvös Loránd University Mathematical physics, Statistical physics Abstract Anyons have been first described by Jon Magne Leinaas and Jan Myrheim in 1977. They are quasiparticles that obey quantum statistics that is more general than that of the Bose-Einstein or the Fermi-Dirac. The name, coined by Frank Wilczek, actually alludes to this: they obey “any” statistics. The talk wishes to introduce the concept of anyons to the audience along with some of the mathematics associated with them. |
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Three dimensional Bose-Einstein correlations in heavy-ion collisionsBálint KurgyisEötvös University High energy physics/ heavy ion physics Abstract In ultrarelativistic heavy ion collisions the medium called Quark-Gluon Plasma is formed for a very short time, and in a very small volume. The hot and explanding sQGP is studied in these collisions with a source of particles called hadrons that reach the detectors. To map out this femtometer scale particle-emitting source one has to measure the femtoscopic correlation functions of identified hadrons with the same charge. Previous measurements have shown, that in sqrt(sNN) = 200 GeV Au+Au collisions, instead of a Gaussian source one should rather consider the more general Levy distributions, which give better description of the observations. With a three-dimensional Levy-analysis we can get information on the different Levy-scale parameters, which describe the physical size of the source created in the heavy ion collisions. Also, with this analysis we obtain information about the Levy index of stability, as well as the strength of the correlation. |
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Axial field induced chiral channels in acoustic Weyl systemValerio PeriETH Zurich Condensed matter, acoustic metamaterials, topological phases of matter Abstract Using super-structures one can effectively change the way that sound waves propagates in space. Topological band theory, known from the description of electrons in solids, provides us with a powerful design-principle for such acoustic metamaterials. Weyl points are robust conical band crossings in three dimensional materials that are monopoles of Berry curvature. When a magnetic field is applied, Weyl points are shifted in momentum space. As a result, in Weyl systems a dispersing chiral channel appear along the direction parallel to the field. The same effect can be realized by strain, which induces an axial gauge field. Here, we present the first observation of chiral channel induced by axial field in a purely classical acoustic metamaterial. | |
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| 17:15 | Jack Woolley Photochemistry 101: A physicist's guide | Patrick Jentsch Cosmology | Alasdair Lennon Using Quantum Technology in the search for Dark Matter | Andre Sobotta Ultrashort low emittance electron beams by injection of electron bunches from nano-sized clusters into laser wakefields | Pedro Vianez Mapping a non-linear Luttinger Liquid using 1D-2D magnetotunelling spectroscopy |
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Photochemistry 101: A physicist's guideJack WoolleyUniversity of Warwick Chemical Physics Abstract Photochemistry is key for life; without light-matter interactions plants would not grow and life would grind to a halt. In humans, overexposure to ultraviolet (UV) regions of the solar spectrum can have dangerous consequences, such as photolesions and melanoma. With these detrimental effects in mind commercial filters (i.e. sunscreens) have been developed to protect us from this overexposure. Ultrafast laser systems, combined with spectroscopic techniques, allow us to explore what happens within the first few nanoseconds after UV photoexcitation of sunscreen filters, and infer their relaxation pathways with femtosecond resolution. This knowledge in turn has facilitated the design of the next generation of chemical filters for use in sunscreens, from a perspective of photostability on an ultrafast timescale, rather than macroscopic properties. In particular Mycosporine like-amino acids, found in corals and algae, present a promising avenue of future research within this field. |
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CosmologyPatrick JentschRuprecht Karls Universität Heidelberg Cosmological Structure Formation using Kinetic Field Theory Abstract Kinetic Field Theory applies methods of Quantum Field Theory to classical systems. Using this we calculated the generating functional, which encodes the time evolution of the initial phase space distribution of the universe. We can then apply operators to the generating functional to extract desired quantities. With that we derived the first analytic expression for the cosmological density fluctuation power spectrum. My task is to calculate the higher moments of the density fluctuation; the Bi- and the Trispectrum. |
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Using Quantum Technology in the search for Dark MatterAlasdair LennonUniversity of Birmingham Quantum Technology Abstract The search for dark matter remains one of the largest problems in modern physics as it should count for a significant part of the universe though we've, so far, been unable to detect the existence of it. One set of theories in dark matter suggests that it could potentially be detectable through the coupling it has with the magnetic spin moment of atoms. The aim of the Global Network of Optical Magnetometers for Exotic physics (GNOME) is to detect this coupling in different setups at distant locations around the world. This talk will focus on how quantum technology can allow us to test this theory, how we designed and built a precision optical magnetometer and to what level of precision is necessary to hopefully detect the link with dark matter. |
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Ultrashort low emittance electron beams by injection of electron bunches from nano-sized clusters into laser wakefieldsAndre SobottaUniversity Düsseldorf/Forschungszentrum Jülich Laser Plasma Physics, Accelerator Physics Abstract We present our approach to a single-stage laser wakefield accelerator with low emittance. We utilize electron bunches, that are emitted from nano-sized clusters when being irradiated by ultrashort high intensity laser pulses. |
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Mapping a non-linear Luttinger Liquid using 1D-2D magnetotunelling spectroscopyPedro VianezUniversity of Cambridge Semiconductor Physics Abstract One-dimensional (1D) systems behave in a significantly different way from their higher-dimensional counterparts as electron-electron interactions can now no longer be neglected. The Tomonaga-Luttinger Liquid (TLL) model is a theory that describes such systems. This model makes a number of predictions, such as spin-charge separation and suppression of tunnelling conductance at zero bias, both of which have been experimentally observed. It makes however some simplifications, such as assuming 1D systems of infinite length and only considering low-energy excitations. Recent theoretical work has focused on extending the TLL theory to include higher energy excitations and finite length systems. This led to the prediction that, at higher order excitations, 'replica' parabolas with higher momenta should be observed, in addition to the simple single-particle parabolic dispersion. My work focuses on the experimental detection and quantification of these higher order excitations using the method of 1D-2D tunnelling spectroscopy in order to map the dispersion of the system. In this talk I will report on current progress including design and fabrication of one-layered and two-layered semiconductor devices with an array of 1D wires. I will also present preliminary data showing successful operation of the gates, as well as discussing our technique for making air bridges. [1] Jompol et al., 2009 Science, 325, 597–601. [2] Tsyplyatyev et al., 2015, Phys. Rev. Lett., 114, 196401 [3] Tsyplyatyev et al., 2016, Phys. Rev. B, 93, 075147. | |
| 17:30 | Katharina Egenolf Structural Colours Inspired by Nature | Tamari Meshveliani Axion Miniclusters: Formation in the Early Universe and Signals in Gravitational Microlensing | Pieter Bouwmeester Electromagnetostatics | Bogdan Butoi High power lasers and their applications | Biljana Mitreska In-plane Second Harmonic Wave Generation in Multiband Organic Conductors |
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Structural Colours Inspired by NatureKatharina EgenolfTechnical University of Kaiserslautern Biophysics, Optics Abstract There are two different reasons for colours: pigments and structures. The latter is based on disorder and found in many natural examples. Methods for mimicing these structures are presented as well as some specimens. |
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Axion Miniclusters: Formation in the Early Universe and Signals in Gravitational MicrolensingTamari MeshvelianiUniversity of Göttingen Cosmology Abstract Axion is a hypothetical elementary particle produced by the spontaneous breaking of Peccei-Quinn symmetry. If this symmetry breaking happens in the radiation dominated epoch in the early Universe, then large amplitude fluctuations in the axion field are present. These fluctuations can gravitationally collapse and form axion miniclusters during the radiation epoch in an early phase of structure formation. Axion miniclusters for the QCD axion have a mass around 10^−12 - 10^−10 M_solar. The goal of the work to characterise the galactic distribution of miniclusters and using microlensing of stars in nearby galaxies to constrain it. Since axions are the best candidates for cold dark matter, microlensing offers an opportunity to discover, or exclude, this important candidate in the classic window of its parameter space being targeted by running and upcoming experiments, ADMX and MADMAX. |
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ElectromagnetostaticsP BouwmeesterLeiden University Electro- and Magnetostatics on quadric surfaces Abstract We try to find the charge distribution and electric field of charged quadratic surfaces and the current density and magnetic field of currents on those surfaces. We will write everything in ellipsoidal coordinates, find the Laplacian and conclude that it is separable to find the (scalar) potential of both. We will use this to find the current density general ellipsoids and two bladed hyperboloids, as well as the current dist. on single bladed hyperboloids. We will also use this to look at the charge distribution of a unit disk, and maybe some other generalizations. The talk might be somewhat math-heavy. |
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High power lasers and their applicationsBogdan Butoi, Andreea Groza, Mihai Serbanescu, Mihai GangiuFaculty of Physics, University of Bucharest Laser physics, particle physics Abstract High power lasers have opened new interesting ways for scientists, being more and more used in applications ranging from space science, medical and particle physics. This work presents a brief overview of the fundamental method of obtaining high intensity laser beams by CPA (Chirped-Pulse Amplification) and some applications that could, in the near future, benefit all of us. One of the most important uses of these high intensity lasers is making table-top accelerators for use in hadron therapy, the use of charged particles in killing cancer. |
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In-plane Second Harmonic Wave Generation in Multiband Organic ConductorsBiljana Mitreska, Danica KrstovskaSs. Cyril and Methodius University Condensed matter physics Abstract The second harmonic wave (SHW) generation from Joule heating as a heat source in multiband organic conductors with two group of charge carriers, quasi-one dimensional (q1D) and quasi-two dimensional (q2D) has been theoretically studied in the plane of the layers. Such are the series of q2D organic conductors α − (BEDT − TTF)2MHg(SCN)4 [M=K, NH4, Rb and Tl] which have attracted considerable attention over the last few years due to two different ground states and rich phenomena associated with them. We consider a case when electric currents, flowing through the conductor are along the most conducting axis, x−axis. The SHW amplitude is analyzed as a function of the magnetic field and the angle between the arbitrary magnetic field and the normal to the plane of the layers. The results are discussed in comparison to the previous work that considers the case of a SHW generated along the least conducting axis, z−axis. We expect our findings to show that the amplitude of the SHW generated in the plane of the layers is much larger than the one of the SHW generated along the direction perpendicular to the layers. The angular oscillations of the wave amplitude are associated with the charge carriers motion on both the cylindrical part and quasi-planar sheets of the Fermi surface in a tilted magnetic field. The changes in the wave amplitude with the field orientation are correlated with the corresponding angular changes in both the electrical and thermal conductivity. We will also investigate the contribution from both the q1D and q2D charge carriers to the observation of the effect. It is expected the group of charge carriers with a q1D energy spectrum to be significantly dominant in the SHW generation in the plane of the layers. | |
| 17:45 | Sophie Dvali Adaptation to Variance of Stimuli in Drosophila Larva Navigation | Giorgi Arsenadze PARTICLES ON THE ROTATING CHANNELS IN THE WORMHOLE METRICS | Sebastián Pereira How to improve the efficiency of any heat engine | Marta Roman Extended phase diagram of RNiC2 family | |
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Adaptation to Variance of Stimuli in Drosophila Larva NavigationSophie DvaliNew York University Biophysics Abstract Sensory systems relay information about the world to the brain, which enacts behaviors through motor outputs. In order to maximize the transmission of information to higher brain regions, early sensory systems discard redundant information through adaptation to the mean and variance of the environment. Here we study the behavioral consequences of adaptation to variance using navigational decisions of fruit fly larvae as a model. We quantify how sensory-motor computations underlying navigation adapt to changes in the variance of visual and olfactory inputs and show that this adaptation can be characterized by rescaling of the sensory input. We find that for both visual and olfactory inputs, the temporal dynamics of adaptation are consistent with an optimal variance estimator. In multisensory contexts, larvae adapt independently to variance in each sense, and portions of the navigational pathway encoding mixed odor and light signals are also capable of variance adaptation. Our results suggest multiplication as a mechanism for odor-light integration. |
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PARTICLES ON THE ROTATING CHANNELS IN THE WORMHOLE METRICSGiorgi arsenadzeFree university Astrophysics Abstract In the Ellis-Bronnikov wormhole (WH) metrics the motion of a particle along curved rotating channels is studied. By taking into account a prescribed shape of a trajectory we derive the reduced 1+1 metrics, obtain the corresponding Langrangian of a free particle and analytically and numerically solve the corresponding equations of motion. We have shown that if the channels are twisted and lag behind rotation, under certain conditions beads might asymptotically reach infinity, leaving the WH, which is not possible for straight co-rotating trajectories. The analytical and numerical study is performed for two and three dimensional cases and initial conditions of particles are analysed in the context of possibility of passing through the WH. Prof. Dr Zaza osmanov. |
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How to improve the efficiency of any heat engineSebastián Pereira, Alejandro JenkinsUniversidad de Costa Rica Classical Physics, History of Physics, Thermodynamics Abstract Carnot’s theorem puts an upper limit to the efficiency of any heat engine. Though in practice it’s impossible to ever reach this theoretical limit, engines could still be improved. We combine Lord Rayleigh’s work on thermoacoustics and Arthur Eddington’s papers on cepheid variables to develop an intuitive criterion to help us understand and improve the efficiency of any heat engine. We call it the Rayleigh-Eddington’s criterion. |
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Extended phase diagram of RNiC2 familyMarta Roman, Kamil K. Kolincio, Tomasz KlimczukGdansk University of Technology Condensed Matter Physics Abstract The rich phase diagram of the low-dimensional rare earth nickel dicarbides RNiC2 in which various ground states such as ferromagnetic, antiferromagnetic, superconducting and charge density wave states have been reported so far, makes the members of this family the appropriate candidates for the investigation of the relations between numerous types of ordering. The ground state of the members of this family depends on the rare-earth metal component denoted by R. The extended phase diagram of RNiC2 family will be presented here. The particular emphasis will be held on five late-lanthanide based RNiC2 compounds (R = Dy, Ho, Er, Tm, Lu) where recently the CDW state has been found by us for the first time. The temperature of the CDW formation was found to be close or above the room temperature (TCDW = 284-463 K) and scales linearly with the unit cell volume. A similar linear dependence has been observed for the temperature of the lock-in transition T1 as well. Beyond the intersection point of the trend lines, the lock-in transition is no longer observed. |
| P: 1 | Mikel Kumria | The Physics of Nuclear Reactors |
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The Physics of Nuclear ReactorsMikel KumriaUniversità di Torino Nuclear Physics Abstract This project is going to focus on the physics of the nuclear reactors, particularly on the nuclear engines, which changed the landscape of the submarines, ships, torpedo, aircrafts, missiles, spacecrafts and other militar and civil propelled engines. |
| P: 2 | Ewa Glimos | NAA and XRF Study of Archaeological Bronzes |
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NAA and XRF Study of Archaeological BronzesEwa Glimos [1], Andrzej Bolewski [1] , Beata Ostachowicz [1] , Paweł Wróbel [1], Karol Dzięgielewski [2]AGH University of Science and Technology Nuclear physics Abstract A subject of this study was a set of 6 bronze artefacts from Pomerania and one from Silesia, Poland. The main goal was to identify types of the materials in use and their origin. To achieve that goal two analytical methods capable of elemental analysis: neutron activation (NAA) and micro X-Ray Fluorescence technique were applied. The neutron activation analysis (NAA) was achieved with 239Pu-Be isotopic neutron source (5x10^6 neutrons/s; ca 2,5 Ci) with the paraffin moderator and HPGe detector. Due to the different shapes of the tested samples and the lack of standard reference materials, the quantitative analysis of the chemical composition of the bronze was not performed. The lines 559 keV, 657 keV and 602 keV, 693 keV, characteristic of As and Sb respectively were registered. Characteristic gamma rays for isotopes Cu, such as the energy 1345 keV, due to the small neutron flux were observed, but the count rate was relatively small. The micro XRF analysis was done with use of the in-house developed laboratory setup consisting the low-power X-Ray tube with polycapillary lens and SDD detector. Due to the very small spot size of the primary beam (~20 µm) it was possible to perform the analysis in the areas not covered by the corrosion. The XRF analysis confirmed the presence of As and Sb and additionally some traces of Fe, Cr, Sn, Pb and Ni were detected. In this work the results obtained for all the samples with NAA and micro-XRF are compared and the capabilities of both methods are discussed. The presence of Cu, As, Sb and Sn in bronzes was detected which proves that the raw material was imported. Additionally the variable content of these elements proves that the tested samples have different origins. This indicates an intensive commercial trade occurring in northern Poland during the bronze age. |
| P: 3 | Fariseu Eduard-Florin | Sea water magnesium fuel cell power supply |
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Sea water magnesium fuel cell power supplyFariseu Eduard-FlorinFaculty of Physics,University of Bucharest Green Energy Abstract Finding new energy sources became nowadays one of the most important research direction, and the term "green energy" is being used more and more. In this field, the alternative of sea water magnesium fuel cell supply attracted a lot of attention. An environmentally friendly magnesium fuel cell system using seawater electrolyte and atmospheric oxygen was tested under practical considerations for use as maritime power supply. Commercial magnesium AZ31 rolled sheet anodes can be dissolved in seawater for hydrogen production, down to a thickness below 100 µm thickness, resulting in hydrogen generation efficiency of the anode of over 80%. A practical specific energy/energy density of the alloy of more than 1200 Wh/kg/3000 Wh/l was achieved when coupled to a fuel cell with atmospheric air breathing cathode. The performance of several AZ31 alloy anodes was tested as well as the influence of temperature, electrolyte concentration and anode - cathode separation. |
| P: 4 | Ronja Speicher | Refining the Sampling and Extraction fpr Groundwater Dating with Radiocarbon |
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Refining the Sampling and Extraction fpr Groundwater Dating with RadiocarbonRonja SpeicherRuprecht-Karls-Universität Heidelberg Groundwater Dating, Environmental Physics Abstract Groundwater dating with radiocarbon (14C) bears the challenge of contamination by atmospheric carbon dioxide. In order to reduce contamination, the sampling and extraction procedures of an existing method are optimized. For this purpose, groundwater samples are taken at six different locations. Five of these sampling sites are located in the Upper Rhine Graben while the sixth sampling site is located in Andernach in the Vulkaneifel. After sampling in two different ways, the CO2 of the groundwater samples is extracted using three different methods. These extraction methods are the existing method and two types of the optimized method. The optimized method extracts once with "normal" acid and once with degassed acid. The aim of the extraction is to obtain the highest possible CO2 amount without water vapour. Thus, the gas is analysed by means of a RGA with regard to its composition. For the optimized method, the gas analysis revealed a higher CO2 content and for most of the samples alongside no water is in the extracted sample. To determine the conventional groundwater age, the extracted gas samples are graphitizied and subsequently measured at the AMS of the Curt-Engelhorn-Zentrum Archäometrie in Mannheim. The determined conventional 14C ages show that optimization leads to a minimisation of the atmospheric carbon contamination. urthermore, the optimized method saves time since shortened extraction times can be used |
| P: 5 | Roshan Kumar Mishra | Application of Wavelet Analysis to Study Strong Ground Motion during The Great Gorkha Earthquake, Nepal 2015 |
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Application of Wavelet Analysis to Study Strong Ground Motion during The Great Gorkha Earthquake, Nepal 2015Roshan Kumar Mishra, Binod Adhikar, Narayan Prasad ChapagainTribhuvan University Geophysics Abstract The trembling of the Earth’s surface due to an unexpected fault rupture within the Earth’s crust is said to be an earthquake. The occurrence of earthquakes is a global phenomenon. It is also believed that the overstressed Earth generate energy in the form of earthquake and volcanoes. In this work, we have studied the strong ground motion after Gorkha earthquake 2015 from different stations. For the better understanding of strong ground motion, we have adopted wavelet analysis. Both continuous and discrete wavelet transform has been implemented. This technique is particularly suitable for the non-stationary signal. In general, it is well recognized that the earthquake ground motion is a non-stationary random process. In order to characterize a non-stationary random process, it requires immeasurable samples in the mathematical sense. The wavelet transformation procedures that we have followed help in the random analysis of linear and non-linear structural systems, which are subjected to earthquake ground motion. The manners of seismic ground motion are characterized through wavelet coefficients associated to these signals. These technique helps to point out the long-period ground motion with site response. Comparing both the horizontal and the vertical motion, it can be observed that the most of the high amplitude signals are associated with the vertical motion, because of the high energy is released in that direction. It is found that the seismic energy is damped soon after the main event, however, the period of damping is different. This can be seen on DWT curve where square wavelet coefficient is high at the time of aftershock and the value decrease with time. |
| P: 6 | Aleksandra Grudskaia | Search for quasimonochromatic gravitational signal using pulsar timing methods |
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Search for quasimonochromatic gravitational signal using pulsar timing methodsNataliya PoraykoLomonosov Moscow State University Astrophysics Abstract Pulsar timing was suggested for detection of low-frequency gravitational waves $(10^{-9} $Hz$< f_{gw} < 10^{-7}$Hz$)$ by Sazhin in 1978 and independently by Detweiler in 1979. Pulsar timing can be used for detection of different types of signal. In particular, it can be used for detection of monochromatic narrow-band signal, that is generated by a scalar field. Such scalar field is described in Chmelnitsky & Rubakov and suggested to be a possible candidate to warm dark matter. A classic scalar field with mass $10^{-23} - 10^{-22}$ eV is considered as warm dark matter. It acts as an ideal liquid with ostillating pressure, and these ostillations cause the ostillations of gravitational potential at frequency $m$, which can be detected using pulsar timing. The effect of these ostillations on pulsar timing is comparable to the effect of a monochromatic gravitational wave with characteristic strain $ h_c \approx 2\cdot 10^{-15} \left( \frac{10^{-23} eV}{m}\right)^2$ and frequency $f=5 \cdot 10^{-9} Hz \left( \frac{m}{10^{-23} eV}\right)$. But unlike usual gravitational-wave background, in case of warm dark matter the signal will be narrow-band and monochromatic and the angle correlation coefficients will not depend on angular distance bteween pulsars. In this work we try to find out if it is in principle possible to detect such a signal from scalar field dark matter using nowadays or future big telescopes. We simulate data sets from SKA/FAST telescope and place upper limits on the amplitude of monocromatic signal as a function of frequency. |
| P: 7 | Viola Gelli | Quasars: a new "standard candle" |
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Quasars: a new "standard candle"Viola GelliUniversità degli Studi di Firenze Astrophysics Abstract Quasars are among the brightest sources observed in the universe and they have a wide emission spectrum. There is a non-linear relation between monochromatic luminosity in X-rays (fixed at 2KeV) and UV (fixed at 2500 ̊A) of Quasars. In this work I studied this relation, checking it and looking for its possible applications in cosmology. Observational cosmology is based on the study of standard candles, i.e. sources characterized by a known luminosity. Through them it is possible to find the luminosity distance DL (function of the redshift z) and to study its trend (in the so called Hubble Diagram) obtaining important informations about the cosmological models. Such studies are generally performed by using Cepheids and Supernovae as standard candles. We wondered whether it is possible to use Quasars as standard candles, taking advantage of the non-linear relation in the form logLX =γlogLUV +β. They would in fact allow us to study the Hubble Diagram at very high redshifts (up to z ∼ 6). I performed an analysis with a sample of 2060 sources, testing this relation and concluding that Quasars represent a powerful tool to estimate the cosmological parameters and to check the models at long distances. |
| P: 8 | Fraser Pike | A breakthrough in exoplanet hunting |
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A breakthrough in exoplanet huntingFraser Pike, Aurélien Benoit, David MacLachlan, Robert ThomsonHeriot-Watt University Astrophysics/photonics Abstract The radial velocity method of detecting exoplanets requires an extremely stable and high resolution spectrograph. Optical fibres help us achieve this, but they suffer from modal noise in the infrared, a spectral region of great importance due to the large number of exoplanets orbiting M-dwarfs. I present a device which offers a modal noise free approach to feeding a spectrograph. We have achieved simulated radial velocity measurements in the region of 50 m/s with an inexpensive spectrograph built with catalogue components by using this photonic approach. |
| P: 9 | Marko Shuntov | Cosmological Parameter Estimation Using Monte Carlo Markov Chains |
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Cosmological Parameter Estimation Using Monte Carlo Markov ChainsMarko ShuntovAix-Marseille Université Cosmology Abstract A cosmological model is parametrized by a set of parameters determining its properties and content. In this work, the concordance model of cosmology is unveiled using data from cosmological probes, and Monte Carlo Markov chains (MCMC) to perform fitting with the model. Data from supernovae of type 1a (SN1a) and baryon acoustic oscillations (BAO) cosmological probes, obtained by observational surveys, is used. The data is fitted with model functions describing the observed quantities using least squares method and Monte Carlo Markov chains. MCMC yield posterior likelihood distributions in the parameter space from which constraints on the cosmological parameters are derived. |
| P: 10 | Marianela Quiros Rojas | Toy model for the structural study of different galaxy redshifts |
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Toy model for the structural study of different galaxy redshiftsMarianela Quiros-Rojas(1), Itziar Aretxaga(2), Alfredo Montaña(2).University of Costa Rica Astrophysics Abstract Galaxies are the fundamental structure that allows us to study the evolution of the Universe. The formation and evolution of galaxies is one of the most active research topics in contemporary astrophysics. In the distant Universe, galaxies are forming. The structure of a spiral galaxy was built: bulb, disk and stellar regions, through the use of the Python programming language. This galaxy comprises an extension of 20 kpc of radius, based on the spiral galaxy M81. For the distribution of surface brightness, the Law of De Vaucouleurs for the bulb and the Exponential Law for the disk were used, in addition to optical and infrared spectra of spiral galaxies for the disk, elliptical for the bulb and irregular for the regions of star formation to extrapolate the emission of the different regions of the galaxy emission from $ z \approx 0.25 $ to $ z \approx 2 $. With this it was possible to study the evolution process, as well as the decrease in angular size of the galaxy to higher redshifts. The appearance of the galactic structure is highly affected by shifts greater than $ z \approx 0.25 $, which makes it difficult to study these regions at infrared wavelengths or greater. |
| P: 11 | Parit Mehta | Simulations of nuclear pasta in neutron stars using quantum molecular dynamics |
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Simulations of nuclear pasta in neutron stars using quantum molecular dynamicsParit MehtaGoethe University Astrophysics Abstract We investigate the properties of nuclear pasta in the inner crust of neutron stars. Extremely high density conditions exist inside a neutron star and nuclear pasta is characterized by complex patterns such as tubes, sheets and bubbles. The crust is modeled within the framework of quantum molecular dynamics (QMD). In this model, nuclear attraction and coulomb repulsion as well as various other interactions are evaluated through QMD. The interactions influence the properties of nuclear matter including liquid-gas phase transitions and transport properties. The dependence of the pasta phase on the isospin properties of the nuclear interactions has been already investigated. These properties are relevant to the dynamics of accreting stars and supernova explosions among other astrophysical scenarios. This is done through simulations using an efficient computer code developed at the Frankfurt Institute of Advanced Studies (FIAS) and some results that build upon previous simulations of nuclear pasta are presented. |
| P: 12 | Ana Bacelj | Study of gamma-ray burst (GRB) correlations via a hierarchical Bayesian model |
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Study of gamma-ray burst (GRB) correlations via a hierarchical Bayesian modelAna BaceljUniversity of Rijeka, Physics Department Astrophysics Abstract Gamma-ray bursts (GRB’s) are short and intense pulses of soft gamma-rays. The bursts last from a fraction of a second to several hundred seconds. They arrive from cosmological distances from random directions in the sky. A key feature of gamma-ray bursts is the observed relation between the instantaneous luminosity and the spectral peak energy within a burst. This correlation, which is known as the hardness-intensity correlation or the Golenetskii correlation, holds important clues to the physics of GRBs. The hierarchical Bayesian model is used to to study the rest-frame Golenetskii correlation on the sample of 27 GRBs with known redshift and pulse-like lightcurves, detected by GBM detector of Fermi space telescope. The Bayesian method used here allows for a better determination of the rest frame properties of the correlation, which in turn allows for more stringent limitations for physical models of the emission to be set. |
| P: 13 | Lamborghini Sotelo | Homodyne Detection and Squeezed states of light |
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Homodyne Detection and Squeezed states of lightLamborghini SoteloCICESE Quantum Optics Abstract Homodyne detection is an interferometric technique that allows us to subtract a piece of information from a quantum state. As we know, it is impossible to measure a quantum state without changing it, so in order to fully characterize a quantum state we need to prepare a set of copies of the same state and perform a series of measurements on each of this copies, we call this set of copies an "ensemble". With enough measurements we can construct a statistical distribution of the probabilities of measuring a state "a" under a certain set of conditions "b", this probabilities are projections of the Wigner function, which is then related to the density matrix of the state. Thus it is possible to reconstruct the density matrix, which describes the entire quantum system from a set of statistical distributions measured through a homodyne technique, this is of great importance for future applications such as quantum computing, quantum teleportation, quantum communications and so on. Squeezed states of light are also of great interest and can also be characterized through this technique. We say that a state is squeezed when one of its quadratures holds a lower variance than that of a coherent state, that is, its uncertainty according to Heisenberg's principle, is lower than the quantum limit. This states of light have been proposed to be implemented at the gravitational-wave observatory LIGO, to enhance its resolution beyond the quantum noise level allowing it to detect weaker signals without losing resolution on other parts of the spectrum. |
| P: 14 | Alessandra Beni | The Bell inequality |
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The Bell inequalityAlessandra BeniUniversity of Florence Theoretical physics Abstract The formalization of Quantum Mechanics challenges some hypothesis con- sidered fundamental in classical physic. The idea that a system could be si- multaneously in many states is in contrast with our common sense. Einstein supported the idea that the probabilistic nature of measurement processes arises from an incompleteness of our description. This idea was considered useful to recognize Quantum Mechanics as a classical theory, although it was incomplete. The Bell's Theorem's demonstration made possible to verify experimentally if this idea could correspond to the reality or not: a violation of Bell's inequal- ity excludes the possibility of Quantum Mechanics to be a classical theory. In my work I gave an extremely general demonstration of Bell's Theorem, based on properties of probability distribution. I also showed how it is possible to verify a violation of Bell's inequality, making local measurements of three spin components on two electrons in a singlet state, that were sent to two different apparatus. This is experimentally very hard to realize. For this reason I also gave a description of the logical scheme of a new class of thought-experiment. |
| P: 15 | Nemanja Micić | Influence of anisotropy and magnetic field on thermal entanglement in Heisenberg model and thermodynamic analysis of model |
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Influence of anisotropy and magnetic field on thermal entanglement in Heisenberg model and thermodynamic analysis of modelM. Pantić, N. Micić, M. Pavkov-Hrvojević , S. Radošević, P. MaliUniversity of Novi Sad Quantum Informatics Abstract The thermal entanglement in a two-qubit anisotropic Heisenberg XXZ system, aslo XYZ system, with Dzyaloshinskii-Moriya (DM) couplings in an inhomogenous magnetic field, was studied. The effects of these two kinds of anisotropies on the thermal entanglement have been studied in detail in the concept for concurrence, the measure of entanglement. The analytical expressions of concurence are obtained for this model. It is found that the DM interaction can enhance thermal entanglement and can be efficiently controlled by the DM interaction parameter and ehchange interaction $J_{x}$, $J_{y}$ and $J_{z}$. When $D$ is large enough, the entanglement can exist for larger temperatures and strong magnetic field. We also analysed thermodynamic properties of Heisenberg model and the most important results were shown in the paper. |
| P: 16 | Alexander Jones | Numerical Solution of the Schrödinger Equation with a Time-Dependent Potential |
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Numerical Solution of the Schrödinger Equation with a Time-Dependent PotentialAlexander JonesUniversity of Portsmouth Quantum Dynamics Abstract MATLAB investigation of frequency and height of a potential barrier and the effect they have on the time evolution of a wave packet using a Crank-Nicolson Scheme solution of the TDSE. Results are shown graphically and the error is 0.000521. |
| P: 18 | Ajdin Palavrić | Probing the Chaotic Behaviour of the Modified Foucault’s Pendulum |
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Probing the Chaotic Behaviour of the Modified Foucault’s PendulumDino Habibović MA, Ajdin Palavrić, Darko KolendaUniversity of Sarajevo Nonlinear Mechanics Abstract In this work we analyze the chaotic behaviour of the modified Foucault’s pendulum. The only modification we introduce to the original Foucault’s pendulum is that we replace the approximately inextensible string used in the original problem with the ideal spring. This configuration enables us to plot the whole spectrum of equations of motion and to study their chaotic structure. The whole study of this chaotic structure is based on control parameters we are able to alter. In the first part we cite the differential equations of motion starting from the Newton’s second law for non-inertial frames. In this part we also quote the approximate expression for the oscillation frequency Ω of the mass attached to the spring, and throughout the further analysis we compare the results obtained using the approximate expression with the exact results obtained by plotting the spectrum. We especially consider the different sets of initial conditions along with different values of the spring and how these parameters influence the structure of our solutions. In the next section, we introduce two different expressions for drag and deduce the asymptotic results for equations of motion. In the last section, we introduce the notion of Poincaré mapping as well as attractors and bifurcations and try to recognize and relate these phenomena using our results. We conclude this work by mentioning several other examples where chaotic structures could be recognized and where similar analysis could potentially be applied. |
| P: 19 | Michał Suchorowski | HUNT FOR A BARE TRUTH – T-QUARK PAIR ANALYSIS |
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HUNT FOR A BARE TRUTH – T-QUARK PAIR ANALYSISMichał Suchorowski, Paweł Drabczyk, Piotr Pigoń, Patrycja Potępa, Iwona Grabowska-BołdAGH University of Science Particle Physics Abstract Quark t, called top or true, was discovered on 2nd March 1995. It is the most massive elementary particle known to scientists, heavier even than Higgs Boson. LHC is called a t-quark factory because in the period of the most intensive data acquisition a t-quark pair was created even more often than once a second. The Standard Model predicts that a t-quark lifetime is 10^-25 s. That time is 20 orders of magnitudes shorter than the time scale for strong interactions, therefore, t quarks do not combine into hadrons. Consequently, physicists have an opportunity to study ‘bare’ quarks. One of the major goals of the ATLAS physics programme is to study and understand t quarks. Knowledge gained during this analysis is essential to understand rare processes as the production of t-quark pair is a background to almost all processes that have leptons and multiple jets in their final states. Understanding its production is seen as one of the necessary steps on the path to discovery of ‘new physics’. The focus of our project is the leptonic channel in which two leptons, such as electrons or muons, are created. Our analysis in based on the ‘ATLAS Open Data’ dataset that is created from the actual data recorded with ATLAS detector in 2012 and Monte Carlo simulations. Events recorded in the data are proton-proton collisions with a centre-of-mass energy of 8 TeV. For the purpose of this project, we adjusted data analysis tools provided within ‘ATLAS Open Data’ to separate events of interest to us from the background in the most precise way. Separation parameters of t-quark pair decay events are useful in the analysis of different processes for which our study could be background. Because of differences in separation parameters, the analysis was ran separately for the decays resulting in the creation of leptons having the same and different flavour. Apart from that, it would allow us to measure physical quantities of t quarks, such as its mass. |
| P: 20 | Marc Huwiler | A search for the $B^0 \rightarrow D_s^+ D_s^-$ decay using multivariate techniques at LHCb |
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A search for the $B^0 \rightarrow D_s^+ D_s^-$ decay using multivariate techniques at LHCbMarc HuwilerEPFL High Energy Physics Abstract The LHCb experiment at the Large Hadron Collider at CERN aims to investigate CP violation through precise measurements of beauty and charm meson decays. The $B^0\rightarrow D_s^+D_s^-$ decay has not yet been observed experimentally. A limit on the branching fraction is currently set at $3.6\cdot 10^{-5}$, which is close to a theoretical computation expecting it at $(1.12\pm 0.15)\cdot 10^{-5}$. A search for the decay $B^0\to D_s^+D_s^-$ is presented in this poster, using the $3{fb^{-1}}$ of Run $1$ data collected by the LHCb experiment. The use of new Deep Neural Network classifiers recently added to the TMVA library is also investigated in the selection process. A small excess of $2$ sigma is measured in the signal region and the use of Run $2$ data was envisaged as a future work. |
| P: 21 | Cornel Staicu | Plasma Physicist |
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Plasma PhysicistCornel Staicu, Paul Dinca, Bogdan Butoi, Corneliu Porosnicu, Cristian LunguUniverstiatea Bucuresti The antibacterial proprieties and characteristics of Cu and Ag films obtained by the Thermoionic Vacuum Arc method Abstract Bacteria, viruses and fungi are found in human habitat and some of these micro-organisms are generating pathogenic strains. Thus, the growth of pathogenic micro-organism on surfaces with which we interact in our everyday life is going to be a threat to human life. People from around the world, like doctors or scientists, are struggling to annihilate them.The ability of bacteria to grow on different surfaces is causing huge concern in hospitals and food industries due to the increased risk of bacterial infection. It was discovered that some metals, for example silver or copper, show some antibacterial properties and they have been used for centuries in different purposes both clinical and non-clinical because of their ability to limit the development of a wide range of micro-organisms. In this study, we saw the effects of interaction between two bacteria, E.coli and S.aureus and our coated surfaces with silver, copper and both of them simultaneously. The surfaces were coated by Thermionic Vacuum Arc method. The morphological and structural properties of the samples were investigated. XRD, RBS, SEM and tribology measurements revealed the textured nature of the samples and also its high roughness. |
| P: 22 | Viktor Jeges | Electron kinetics in low temperature plasmas |
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Electron kinetics in low temperature plasmasJeges Viktor PéterEötvös Loránd University plasmaphysics Abstract Characteristics of electron swarms were investigated in a scanning time-of-flight drift tube apparatus with special interest in their non-equilibrium behaviour. These studies have been conducted using argon gas and were paired with a Monte-Carlo based particle tracking simulations. Both the experimental and simulation results showed the Franck-Hertz phenomenon close to the electron source (cathode) at reduced electric field values within the range of E/N = 10-100 Td, at 200 Pa pressure. The experiment then was repeated with added molecular gases to see if the lower excitation energy levels of these gases would smooth the electron density profile and set a steady swarm. The results indeed showed that under such conditions the hydrodynamic equilibrium in the electron transport establishes much earlier and persists along the tube. |
| P: 23 | Mirko Rossini | Cluster versus single-particle hopping in a colloidal model |
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Cluster versus single-particle hopping in a colloidal modelMirko Rossini, Andrea Stenco, Lorenzo Consonni, Nicola Manini, Luciano ReattoUniversità degli Studi di Milano Computational analysis Abstract We study a two-dimensional model for interacting colloids which is consistent with cluster states, adding a periodic corrugation potential and an external force. For different colloidal densities and different amplitude of the periodic corrugation potential we investigate the depinning from the static to the sliding regime. In the sliding states we characterize the competition between a dynamics where entire clusters are pulled from a minimum to the next and a dynamics where single colloids or smaller groups leave a cluster and move across the corrugation barrier to join the next cluster. |
| P: 24 | Bohdan Opryshko | The speed of sound in molecular model fluids in the approximation of tight bound hard spheres |
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The speed of sound in molecular model fluids in the approximation of tight bound hard spheresOpryshko B., Grygoriev A.Taras Shevchenko National University of Kyiv Molecular Physics Abstract The density, adiabatic modulus of elasticity, enthalpy, speed of sound in the approximation of tight bound hard spheres in a wide range of densities and pressures are calculated by the Monte-Carlo method in isobaric-isoenthalpy ensemble. The shape of the particles varied (imitating the molecules of ortho-, para-, and the metaxylenes), but the volume of the particle did not change |
| P: 25 | Veronika Shapar | Study of the structure and dynamics of chlorpropamide applied in pharmacology |
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Study of the structure and dynamics of chlorpropamide applied in pharmacologyVeronika ShaparTaras Shevchenko National University of Kyiv Molecular physics Abstract The goal is to find the polymorph phase transition in chlorpropamide under the influence of high pressure with the usage of energy – disperse roentgen diffraction and to study the changes of crystallite structure up to the pressures of 5 GPa. The diffraction spectrums of chlorpropamide at the different values of pressure were obtained. The comparison of experimental data with the theoretically evaluated positions of diffraction peaks and its intensities was made. Using the Ritveld method, the parameters of elementary cell of chlorpropamide for the different polymorph forms were evaluated from the diffraction patterns and the corresponding coefficients of linear compressibility were calculated. |
| P: 26 | Alessandro Lupo | Optical nanoantennas |
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Optical nanoantennasAlessandro LupoUniversità degli studi di Bari Nanophotonics Abstract Metallic nanostructures can act as an antenna for light. Here I will show how could this make possibile to confine the light below the diffraction limit and some application to optoelectronics and near field microscopy. Part of my bachelor's thesis, achieved at < |
| P: 27 | Ielyzaveta Shapar | Formation of Textures in the Dried Na-DNA films at Different Concentration of DNA in the System |
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Formation of Textures in the Dried Na-DNA films at Different Concentration of DNA in the SystemI.Shapar, PhD; O.Zagorodnia, PhD,Taras Shevchenko National University of Kyiv Molecular physics Abstract This paper is concerned with experimental study of study on the texture, which is formed on the film surface after drying an aqueous solution of the DNA molecule with the addition of salt NaCl at temperatures of 20 ° C and 42 ° C. Pluchennye texture fotograirovalispri a microscope in light vidimomom with fotookulyarom The results showed that the DNA induces the formation of texture on the surface of the films. Samples without DNA after visushuvantya not form texture. To study the structure of the film Especially we developed a special computer program. Plotting the ratio of the area to the total surface area texture of the film from the DNA concentration in the initial solution. Designed rozmernost fractal texture, the value of which varies in the range from 1.5 to 1.8. With increasing concentration of DNA in the original system area texture increases. Form texture depends ottemperatury. To explain the mechanism of formation of texture films DNA, built a model that inventory quality education experimentally observed textures DNA. Keywords: dried films, texture, fractal dimension. |
| P: 28 | Irene Goti | Optical spectroscopy of molecular iodine for a new frequency reference at 556nm |
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Optical spectroscopy of molecular iodine for a new frequency reference at 556nmIrene GotiUniversità degli Studi di Firenze Physics of Matter Abstract The purpose of this work is to find a frequency reference at 556 nm for the stabilization of the laser employed in laser-cooling experiments with Yb atoms. To this aim the iodine spectrum in this frequency range was studied, focusing in particular on the line X →B P49(24-1). The hyperfine structure was determined using saturated absorption spectroscopy and the first derivative signal, that have a better profile for the laser stabilization, was obtained for three selected lines. |
| P: 29 | Michał Jurkowski | Phase transitions in LaNb$_{1-x}$As$_x$O$_4$ (x = 0.05 to 0.30) |
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Phase transitions in LaNb$_{1-x}$As$_x$O$_4$ (x = 0.05 to 0.30)Michał Jurkowski, Jaroslav Dzisevič, Piotr Winiarz, Sebastian Wachowski, Maria GazdaGdańsk University of Technology Material science Abstract In the evolution of civilization, transport plays leading role [1]. Transport still mainly based on engines
that convert chemical energies of fossil fuel to mechanical energy [2] and due to burning fossil fuels causes increasing environment pollution [3]. |
| P: 30 | Michael Sonner | Multifractality of wave functions on a Cayley tree: From root to leaves |
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Multifractality of wave functions on a Cayley tree: From root to leavesM. Sonner, K. S. Tikhonov, A. D. MirlinKarlsruhe Institute of Technology Condensed Matter Theory Abstract We explore the evolution of wave-function statistics on a finite Bethe lattice (Cayley tree) from the central site (“root”) to the boundary (“leaves”). We show that the eigenfunction moments Pq=N⟨2q(i)⟩ exhibit a multifractal scaling Pq∝N−τq with the volume (number of sites) N at N→∞. The multifractality spectrum τq depends on the strength of disorder and on the parameter s characterizing the position of the observation point i on the lattice. Specifically, s=r/R, where r is the distance from the observation point to the root, and R is the “radius” of the lattice. We demonstrate that the exponents τq depend linearly on s and determine the evolution of the spectrum with increasing disorder, from delocalized to the localized phase. Analytical results are obtained for the n-orbital model with n≫1 that can be mapped onto a supersymmetric σ model. These results are supported by numerical simulations (exact diagonalization) of the conventional (n=1) Anderson tight-binding model. |
| P: 31 | Octavian-Gabriel Simionescu | Thin oxide film deposition by RF magnetron sputtering |
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Thin oxide film deposition by RF magnetron sputteringOctavian-Gabriel Simionescu, Gheorghe Dinescu, Marian Băzăvan, Bogdan Biță, Cosmin Romanițan, Florin ComănescuFaculty of Physics, University of Bucharest / National Institute for R&D in Microtechnologies Solid State Physics, Nanotechnologies Abstract RF magnetron sputtering has open large areas of research in microelectronics and solid state physics. Even though this process is more expensive than DC magnetron sputtering it is absolutely necessary for the deposition of dielectric films. Excellent adhesion, high deposition rate and purity has placed this technique in a leading position in its field. Deposition processes divide into two large categories: Physical Vapor Deposition (PVD) and Chemical Vapor Deposition (CVD), each of them splitting into several subcategories. RF magnetron sputtering is situated in the PVD category. The purpose of this poster is to show how the parameters of the deposition can influence the final result. We have used both reactive and non-reactive deposition techniques to deposit thin films of titanium oxide and respectively zinc oxide doped with aluminum on silicon substrates. For the reactive TiO2 depositions, the stoichiometry and the crystalline phases in respect to the amount of reactive gas used were studied by EDX and XRD respectively. For the non-reactive ZnO depositions we studied the deposition rates dependency of the sputtering power and pressure by SEM and ellipsometry. |
| P: 32 | Nikodem Stolarczyk | First Comprehensive Dataset Of Beyond-Voigt Line-Shape Parameters From Ab Initio Quantum Scattering Calculations For The HITRAN |
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First Comprehensive Dataset Of Beyond-Voigt Line-Shape Parameters From Ab Initio Quantum Scattering Calculations For The HITRANNikodem StolarczykNicolaus Copernicus University spectroscopy - molecular spectra Abstract Molecular collisions are manifested as a perturbation of the shapes of molecular optical resonances. Therefore, on the one hand, the line-shape analysis of accurate molecular spectra constitutes an important tool for studying quantum scattering and testing ab initio molecular interactions [1]. On the other hand, the collisional effects can deteriorate the accuracy of atmospheric measurements of the Earth and other planets, modify the opacity of the exoplanetary atmospheres as well as influence the accuracy in optical metrology based on molecular spectroscopy [2,3]. Recently a new relational structure has been introduced to the most extensively-used line-by-line spectroscopic database HITRAN [4,5], enabling the collisional, beyond-Voigt line-shape effects to be represented. It is, however, extremely challenging to populate the entire database with purely experimental parameters for all the molecular transitions and thermodynamical conditions (all the bands, branches and temperature ranges). We demonstrate a new methodology of generating a comprehensive dataset of the beyond-Voigt line-shape parameters from fully ab initio quantum-scattering calculations. We also demonstrate first such a complete dataset for the benchmark system of helium-perturbed H2 line. We provide the temperature dependences for the pressure broadening and shift parameters, as well as for the Dicke parameter using generalized spectroscopic cross sections resulting from quantum scattering calculations on accurate ab initio potential energy surfaces. The results are consistent with the recently adapted HITRAN parameterization of the Hartmann-Tran profile [4]. The calculations and methodology are also validated on the ultra-accurate experimental data of the H2-He system. References: [1] Wcisło P. et al. 2015 Phys. Rev. A 91, 052505. [2] Moretti L. et al. 2013 Phys. Rev. Lett. 111, 060803. [3] Wcisło P. et al. 2016 Phys. Rev. A 93, 022501. [4] Wcisło P. et al. 2016 J. Quant Spectrosc. Radiat. Transfer 177, 75-91. [5] Gordon I. E. et al. 2017 J. Quant. Spectrosc. Radiat. Transfer 203, 3 – 69. 3. 1) |
| P: 33 | Zama Teodora Maria | Basics of Atomic Physics |
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Basics of Atomic PhysicsZama Teodora MariaFaculty of Physics , University of Bucharest Atomic Physics Abstract In this paper we are going to enter upon the subject of the Basics of Atomic Physics. The concept of the atom dates back from Antiquity, when multiple philosophical assumptions about the existence of a “thing” that stands at the foundation of what we know today to be matter, were born. This idea was scientifically proven for the first time in 1803 by the British chemist John Dalton, and the first atomic model was theorized in the final years of the same century by his compatriot physicist J.J. Thompson. Their work was followed by that of many others until we reached the point when we fully understood the atomic structure and its properties. In the following presentation, we are going to talk about some fundamental theories that belong to the vast domain of Atomic Physics, like Thermal Radiation and Blackbody Radiation. Also, we will make a comparison between the Photoelectric Effect and the Compton Effect. To approach this presentation from a practical perspective too, not only from a theoretical one, we will discuss some reviews over experiments that further support the theory , as well as some examples of objects that behave approximately like blackbodies, starting from ordinary objects such as the filament in an incandescent light bulb and reaching even some large-scale objects like the astronomical ones. |
| P: 34 | Jaroslav Dzisevic | Influence of As substitution on the structure of LaNbO4 |
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Influence of As substitution on the structure of LaNbO4Jaroslav Dzisevič, Michał Jurkowski, Maria Gazda, Sebastian Wachowski, Piotr WiniarzGdansk University of Technology Material science Abstract The development of industry and transportation induces growth in energy demand across the globe [1]. Despite many international-level efforts nowadays energy sources are still primarily basing on fossil fuels [1,2]. For instance in transportation the most popular energy source are the Internal Combustion Engines (ICEs), in which chemical energy of the fuels is converted into mechanical in combination with low heat efficiency and a handful of dangerous pollutants released into the environment. Given the above, replacing conventional energy sources (such as ICEs) with new environmental friendly and economically feasible solutions has become growing issue over the last few decades [3,4]. Promising examples of clean energy sources are proton ceramic fuel cells (PCFC). High temperature proton conductors used as an electrolyte in PCFCs are typically ternary oxides given by chemical formula of ABO3 [5], ABO4 [6] or similar [7]. One of the compounds belonging to ABO4 family is LaNbO4. It is expected LaNbO4 to be highly beneficial as electrolyte in fuel cell. Expected benefits go as follows: mechanical endurance at working temperature, high stability in vapor water and carbon dioxide environments. LaNbO4 at the range of specific temperature [490°C - 530°C] can be distinguished in two phase transitions: monoclinic at < 490°C temperatures and tetragonal at < 490°C. Phase transition of LaNbO4 has influence on the compound’s properties as thermal expansion and activation energy. Phase transition of LaNbO4 has disadvantageous impact for applying it as fuel cell electrolyte. To decrease disadvantages of phase transition of current chemical compound assists isovalent doping to B-site of ABO4 with chemical element which has other ionic radii than B. This poster represents analysis of acquired data from doping with As to B-site of LaNbO4. Images of LaNb1-xAsxO4 (x = 0.05 to 0.3) surface and Rietveld analysis of the X – ray diffraction patterns are exhibited in the poster. References: [1] "Transportation sector energy consumption" https://www.eia.gov/outlooks/ieo/pdf/transportation.pdf [2] "Consumption of energy" http://ec.europa.eu/eurostat/statistics-explained/index.php/Consumption_of_energy [3] John P. Lemmon "Reimagine fuel cells" http://www.nature.com/news/energy-reimagine-fuel-cells-1.18392 [4] "Ambient (outdoor) air quality and health" http://www.who.int/mediacentre/factsheets/fs313/en/ [5] Katahira K., Kohchi Y., Shimura T., Iwahara H. 2000 "Protonic conduction in Zr- substituted BaCeO3". Solid State Ioncs 138: 91- 98 [6] Mielewczyk- Gryń A., Gdula-Kasica K., Kusz B., Gazda M. 2012. "High temperature monoclinic-to-tetragonal phase transition in magnesium doped lanthanum orto- niobiate" [7] Omata T., Otsuka-Yao-Matsuo S. 2001. "Electrical propertiesof proton-conducting Ca2+ doped La2Zr2O7 with a pyrochlore- type structure" |
| P: 35 | Agnieszka Wiciak | Elimination of the ripening process during the preparation of nucleation centers for the growth of Si Nanowires |
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Elimination of the ripening process during the preparation of nucleation centers for the growth of Si NanowiresAgnieszka Anna Wiciak, Felix Lange and Torsten BoeckPoznan University of Technology Material physics Abstract Nanowires (NWs) are one-dimensional crystalline objects with specific physical properties due to their reduced dimensionality. The growth and handling of NWs is a challenging task. The creation of these nanostructures with high reproducibility, high ratio of length to diameter, high areal density and perpendicularly to the substrate is highly needed for a reliable technology to create applications (such as solar photovoltaics, light-emitting devices, thermoelectrics, Li-ion batteries, supercapacitors etc). Similar to other nanomaterials, there are two main approaches to fabricate Si NWs: top down and bottom up. While the top down approach consists of an etching process where a lot of material is lost, the bottom-up method is a procedure of accumulating Si atoms in a one-dimensional structure of NWs. One of the main growth techniques for the bottom up approach that achieves high-quality Si NWs is Molecular Beam Epitaxy (MBE). The MBE takes place in an ultra-high vacuum, where a uniform flux of material is deposited onto the substrate surface. The growth of Si NWs in MBE base on the vapour–liquid–solid mechanism (VLS), where eutectic Si-Au droplets are formed to catalyse the NW growth. Obtaining Si-Au droplets with high area density and small droplet diameter at lower process temperatures is desirable for growth Si NWs. But, when rising the temperature an undesirable droplet ripening process results and the droplet density decreases while the droplet diameter increases. Therefore, the droplets need to be fixed at their positions before the NW growth is initiated. Two approaches have been used for this purpose: (1) Depositing of amorphous Si (a-Si) on top of the Si-Au droplets after cooling the sample below the eutectic temperature with a subsequent heating to a higher growing temperature. (2) Implementation of an oxidizing step after the droplet formation. To investigate and compare the resulting samples SEM were used and the results were statistically evaluated. For the a-Si layer approach it was crucial to create an accurate thickness of a-Si layer, to avoid the droplet ripening process. After the following heating, a faultless amorphous Si layer should surround the Si-Au droplets and prevent the ripening process. When the layer is too thin after substrate temperature rising, the droplet area density decreases, while the droplet diameter increases. Whereas a too thick a-Si layer covered the Si-Au droplets, which prevent the Si NWs to grow. The process of forming the oxide layer is based on oxidation Si substrate between droplets after gold deposition. Which effected slowing down the ripening process at the same time it distorts the samples equilibrium. As a result, oxidation allows to grow Si NWs with a higher yield, but during the growth process, Si NWs will change shape, due to the delay following ripening process. |
| P: 36 | Vlad Andrei Basceanu | Enhancing the performance of microbial fuel cells (MFCs) with nitrogen-containing carbon nanostructures modified anodes |
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Enhancing the performance of microbial fuel cells (MFCs) with nitrogen-containing carbon nanostructures modified anodesVlad Andrei Basceanu, Robert Ali Maaz and Anca DumitruUniversity of Physics, University of Bucharest Material Science Abstract Microbial fuel cells (MFCs) are a promising technology which converts organic matter into electricity with the help of exoelectrogenic bacteria present in the wastewater. The surface characteristic of anode materials is one of the deciding factors that affect bacterial attachment and electrical connections between bacteria and the electrode surface. Introduction of nitrogen-containing functional groups at the anode surface could be a useful method to improve microbial adhesion and power generation of MFC. Conversion of polymer precursors to the nitrogen-containing carbon nanostructures (NCNs) has drawn much attention especially because of their excellent electrocatalytic activities as well as low cost. The aim of this study is the investigation of power generation of MFCs using anodes modified with NCNs from polypyrrole (PPY) and polyaniline (PANI) precursors compared with unmodified anode. NCNs were obtained by the carbonization of polypyrrole and polyaniline nanostructures under nitrogen atmosphere at 900 C. |
| P: 37 | Andrew Hunter | Rydberg molecules |
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Rydberg moleculesAndrew L Hunter, Alex Eisfeld, Jan-Michael RostMax Plank Institute for the Physics of Complex Systems Atomic physics Abstract A Rydberg atom in the presence of a neutral perturber is investigated using scattering theory. Due to a negative s-wave scattering length at low energies these perturbers can form a bound state with the Rydberg atom, known as a trilobite molecule [1]. These molecules interact strongly with their environment due to their large polarisability or dipole moment [2]. In particular, we study how such systems change with the addition of multiple perturbers. References [1] C. H. Greene, A. S. Dickinson, and H. R. Sadeghpour, Phys. Rev. Lett. 85, 2458 (2000) [2] P. J. J. Luukko and J. M. Rost, Phys. Rev. Lett.119, 203001 (2017). |
| P: 38 | Nuno Caçoilo | Tuning the magnetic anisotropy in perpendicular magnetic tunnel junctions (pMTJ) by means of ion irradiation |
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Tuning the magnetic anisotropy in perpendicular magnetic tunnel junctions (pMTJ) by means of ion irradiationNuno Caçoilo, Bruno Teixeira, Andrey Timopheev, Stephane Auffret, Ricardo Sousa, Bernard Dieny, Eduardo Alves, Nikolai SobolevUniversity of Aveiro Spintronics, Ion Irradiation, Magnetism Abstract Perpendicular magnetic tunnel junctions (pMTJs) with a free layer (FL) exhibiting an easy-cone anisotropy (EC) may lead to a faster switching in STT-MRAMs (Spin Transfer Torque Magnetic Random Access Memories). As the EC is only found within a confined range of layer thicknesses, it would be advantageous to induce such EC after deposition of the layers. One elegant technique to locally modify structural and magnetic properties is ion irradiation. In this work it will be shown that it is possible to manipulate the magnetic anisotropy by means of 400 keV Ar+ ion irradiation. As a first step to this goal we conducted a ferromagnetic resonance study in a FL stack of MgO/FeCoB/X/FeCoB/MgO (X= Ta, W), with different thickness (2.6 and 3.0 nm), before and after the ionic irradiation. It was observed that the first order anisotropic field is reduced with the increasing Ar+ fluence for the first series of samples (3.0nm), originally in an easy-plane regime. This drove the samples further into the previous regime. Thus, it was expected that, by irradiating a thinner set of samples (2.6nm), originally in the easy-axis regime, the desired EC would be obtained. This was indeed attained for the X=W samples. It was thus concluded that particle irradiation can be used to manipulate the magnetic anisotropy fields and induce an EC in the FL typical of the pMTJ. Furthermore, the irradiation effect did not increase the Gilbert damping parameter, which is vital for a low current density in STT-switching. |
| P: 39 | Stuart Crane | Molecular Dynamics with a Soft Thermal-Desorption Source |
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Molecular Dynamics with a Soft Thermal-Desorption SourceStuart CraneHeriot-Watt University Spectroscopy Abstract Rapid and efficient energy redistribution processes in biological chromophores following ultraviolet (UV) absorption are believed to be a vital ingredient in providing biological photoprotection. Important examples include the DNA bases and the melanin pigments. Gas-phase spectroscopic techniques provide a valuable insight into the fundamental dynamics of these mechanisms, free of intermolecular and solvent effects. However, many large molecules of interest have low vapour pressures, with a propensity to decompose under vigorous heating, making gas-phase spectroscopy difficult. This work presents a soft thermal desorption technique, incorporated within a time-of-flight mass spectrometer (TOFMS), facilitating studies of the UV-photoprotection in non-volatile model biological chromophores. Back irradiation of a thin metallic foil by a CW laser produces neutral plumes of the molecule of interest. Relaxation dynamics following UV absorption in biologically relevant molecules have been investigated using time-resolved pump-probe photoion yield measurements. Further work includes the design of a novel nozzle system to facilitate molecular pick-up, increasing sample concentration and producing partial molecular cooling. |
| P: 40 | Maksym Rusyniak | Research photovoltaic effect in the structure of squaraine dye and fullerene C60 |
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Research photovoltaic effect in the structure of squaraine dye and fullerene C60M.M. RusyniakIvan Franko National University of Lviv Nanocomposite Abstract "By the thermal vacuum deposition technics the layer wise photovoltaic cells squarine dye/C60 were fabricated. The absorption spectrum of thin films of squarine dye, C60 and their layer wise structure were obtained as well. Wе derived photovoltaic parameters of our elements. For the best of them, an open-circuit voltage was 380 mV. The open-circuit voltage dependence of the wavelength were obtained. By virtue of atomic-force microscopy we acquired the results which shows us that fullerene’s film surface is a quite uniform, despite of dye’s film that is susceptible to form island surface." |
| P: 41 | Andrea Ristori | Stimulated emission in microstructured perovskites |
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Stimulated emission in microstructured perovskitesRistori A., Biccari F., Francioni C., Gabelloni F., Vinattieri A.University of Florence Physics of Matter Abstract In this work we studied some physical characteristics of a microwire made of perovskite, whose chemical formula is CH3NH3PbI3. We studied how the photoluminescence changes according to the exciting power, finding a laser-like behaviour. We also measured the time evolution of the photoluminescence and its polarization, discovering that they were similar to a laser one. |
| P: 42 | Edwin Alexandru Laszlo | Simulation and Optical Measurements for Optical Alignment System designed for Space Applications |
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Simulation and Optical Measurements for Optical Alignment System designed for Space ApplicationsEdwin Alexandru LASZLO, Constantin TIBEICA, Munizer PURICAUB, Faculty of Physics Optoelectronics Abstract In the work on optical alignment systems, we have concentrated our efforts to design two applications for the possibility of being used in the Low Earth Orbit. Firstly, due to the accelerated development of space based technologies, which has the obvious disadvantage of an increasing population of uncontrollable non-functional residues (failed satellites, rocket stages) which in turn pose serious risks to ongoing missions, we focus on the development of an optical alignment system (OAS) for autonomous missions to intercept and deorbit space debris. Secondly, due to the fact that the autonomous flying formations became of great importance for the present and future missions (both for spacecrafts and in particular for satellites), the other activity that we have focused on is the development of an OAS to be used in rendezvous or formation flying missions. For both applications, there exist a common root, namely the OAS consisting in a new concept/design LIDAR (Light Detection and Ranging) system with new alignment techniques. They are based on emitters (laser diodes) and photodetectors as receptors, mounted in matrix configurations, different for each application. In the predesigning phase, we faced a problem dealing with the measurements to determine the divergence of the beam after leaving the system as a function of the propagating distance in order to minimize the spot for a proper detection. The simulations and the obtained results will be presented. For small distances, the optical power of the emitting diode can be detected, but for long distances, the optical power would be distributed on a too big divergence, reason why, using a converging glass lens would be more fitted for the proposed applications. Those results were compared and are in accordance with theoretical models. The intensity distribution of a Gaussian beam at various places was also determined and will be presented. Further will be examined how the temperature affects the emitting diodes characteristics and the spectral response of the photodiodes. |
| P: 43 | Jakub Jambrich | Construction of vectorial magneto-optical magnetometer for magnetic nanostructures studies |
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Construction of vectorial magneto-optical magnetometer for magnetic nanostructures studiesJakub JambrichCharles University Magnetooptics Abstract Current research in the field of spintronics calls for high sensitivity characterization techniques to get the information about spin-order at nanoscale. Magneto-optical methods are widely used due to their non-contact and non-destructive nature, sensitivity comparable to SQUID devices and depth sensitivity. Moreover, a complete description of magnetization vector can be extracted from sets of experimental data. This allows for the observation of weak spin related phenomena such as spin accumulation or proximity effects at interfaces. In this work we present a novel experimental setup of magneto-optical magnetometer utilizing white continuum laser. Such approach allows to precisely tune the wavelength of incident light and modulate its intensity with frequency up to 24 kHz. The magnetic field can be applied in-plane as well as out-of- plane with respect to the sample’s plane. The experimental setup employs NKT SuperK COMPACT supercontinuum laser with broad spectral tunability range from 450 to 2400 nm and variable repetition rate from 1Hz to 20 kHz. The pulse signal output is directly connected with lock-in amplifier allowing synchronic detection and increasing signal to noise ratio. The magneto-optical detection is done employing wollaston prism and differential detector. The ability of the setup is presented on set of various thin films of magnetic materials including metals and insulators. Wavelength dependent Faraday hysteresis loops of magnetic garnets as well as Kerr hysteresis loops of GdFe were measured. The signal to noise ratio dependence on modulation frequency is systematically discussed. |
| P: 44 | Tsotne Dadiani | Light rings in the falling liquid jet |
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Light rings in the falling liquid jetTsotne DadianiTbilisi State University Geometric optics Abstract The poster is about phenomenon which occurs in the falling liquid jet, while impact point ( area where jet falls on the perpendicular white surface) is illuminated by a laser beam. light rings appear all along the jet. Iluminated "water fall" itself has complex form, instead of coun it has more like wave formed surface depending on how tall is jet, initial speed of the liquid, initial diameter , liquid surface tension and so on. We study the phenomenon and its dependance on various parameters. |
| P: 45 | Iuliana Taran | THE ANALYSIS OF DOSIMETRIC DETERMINATIONS IN CLINICAL RADIOTHERAPY PRACTICE WITH LINEAR ACCELERATOR |
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THE ANALYSIS OF DOSIMETRIC DETERMINATIONS IN CLINICAL RADIOTHERAPY PRACTICE WITH LINEAR ACCELERATORIuliana Taran, Alexandru Jipa, Mihai Teodor DumitracheUniversity of Bucharest Medical Physics Abstract Radiation measurements and investigations of radiation effects requires different specifications of the radiation field at the point of interest. One of the most important steps involved in the determination of the absorbed dose distribution in the patient requires measurements with a detector (dosimeter) in a water phantom placed in the radiation field. Such measurements include the determinations of the absolute dose at a reference depth in a reference-size field relative doses at many positions in the phantom in order to map out a complete dose distribution and so-called in-vivo doses on the patient’s skin during treatment. This paper will cover analysis of dozimetric determinations using ionization chamber type 30013 Farmer, PTW Unidos Webline and Varian Unique Accelerator. |
| P: 46 | Teemu Virtanen | Study of possible relation of intracranial air and postoperative electrode displacement in bilateral DBS. |
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Study of possible relation of intracranial air and postoperative electrode displacement in bilateral DBS.Based on article (I am senior auth) supervised by the head medical physicist of Oulu Univeristy Hospital Jani KatiskoOulun Yliopisto Medical physics Abstract Background: Deep brain stimulation (DBS) surgery is considered safe and effective way to improve the quality of life of Parkinson’s disease (PD) patients. The bilateral DBS operation surgery allows intracranial air to enter the patient’s brain via the burr hole in patients skull. Postoperative migration of the electrodes in DBS surgery is a known issue, however, the causes which lead to electrode migration (EM) are yet relatively unknown. Objective: Study the amount of intraoperative intracranial air (ICA) in PD patients of patients brain who have been performed bilateral DBS targeting subthalamic nucleus (STN). Electrodes implanted during the surgery are also studied for their possible postoperative migration from the intraoperative location. Comparison of ICA and EM between left and right hemisphere is also studied. The objective is to analyze the possible correlation between ICA and the postoperative EM. Patients and Methods: Group of 18 Parkinson’s Disease patients who have had bilateral DBS surgery performed had their preoperative CT, intraoperative MRI and post-operative CT-scans analyzed to study the amount of ICA. Electrode migration was studied as the difference of the electrodes intraoperative and postoperative locations. Mathematical and statistical analysis of EM and ICA was used for defining the possible correlations between the direction of EM, age of patient and other surgical parameters. |
| P: 47 | Felicia Mihai | Modulation of the Intracranial High-Frequency Stimulation Waveform |
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Modulation of the Intracranial High-Frequency Stimulation Waveform1.Mihai Felicia, 2.Prof. Dr. Andrei BarboricaFaculty of Physics-University of Bucharest Medical Physics, Neurology, Medical Science Abstract Stereoencephalography (SEEG) methodology is progressively gaining popularity for the presurgical invasive evaluations of drug-resistant epilepsies. This method allow us to virtually access any cortical and subcortical area using depth electrodes placed in functionally relevant structures and to record the electrical activity. In this study, we are using the alternating polarity (AP) 50 Hz biphasic stimulation protocol, where the phase of each pulse is inverted from pulse to pulse. For such a stimulation pattern, all artefactual responses that propagate through volume conduction, capacitive coupling or electromagnetic interference, will follow the alternating polarity of the stimulation waveform. The calculation of an effective connectivity within the brain is a consequence of the causal interactions between brain areas, which can only be determined by depth electrodes stimulation. The study reveals that during brain stimulations, certain brain post-discharging may occur which may have effects the waveform and they can influence the brain structures, conducting to maping disruptions. In order to avoid this charges, we are trying to focus only on simple clinical symptoms. This method allows us to evidence the activation of specific pathways in the brain, when a clinical symptom is evoked by an electrical stimulation. |
| P: 48 | Cristina - Alexandra Constantin | Luteolin effect against cancer cells |
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Luteolin effect against cancer cellsCristina Constantin, Mihaela Bacalum, Claudia ChilomUniversity of Bucharest Medical Science Abstract Luteolin is a flavonoid which is part of our daily nutrition in relatively low amounts (less than 1 mg/day). Nevertheless, some epidemiological studies suggest an inverse correlation between luteolin intake and the risk of some cancer types. Luteolin can delay or block the development of cancer cells in vitro and in vivo by protection from carcinogenic stimuli, by inhibition of tumor cell proliferation. Luteolin has been shown to penetrate into human skin, making it also a candidate for the prevention and treatment of skin cancer. The aim of this study was to determine the effect of Luteolin against four cell lines: one normal cell line (L929 – mouse fibroblasts) and three cancer cell lines (Hep G2 – human hepatocellular carcinoma, HT-29 – human colorectal adenocarcinoma and MG-63 – human osteosarcoma). Cells were tested with concentration of Luteolin between 0 - 500 µM for 24 h and cell viability was estimated using the MTS assay. The test showed that L929 cells were the most affected by Luteolin treatment, while HT-29 cells were the most resistant to the treatment. |
| P: 49 | Loredana Militaru | Couch attenuation impact on VMAT prostate cancer treatments |
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Couch attenuation impact on VMAT prostate cancer treatmentsLoredana Elena Militaru, Mihai Suditu, Matei BaraUniversity of Bucharest - Faculty of physics Medical Physics Abstract During last years Volumetric Modulated Arc Therapy (VMAT) has become one of the most used technique for prostate cancer treatment. The use of VMAT in prostate cancer treatment allows conformal dose to the target and reduced dose to the surroundings healthy tissues.Radiation therapy treatment using VMAT is delivered by rotating radiation source around the patient. The aim of this study was to evaluate the dosimetric impact of beam attenuation by Elekta iBEAM evo treatment couch. Firstly, was evaluated the impact of couch attenuation for static beams by measuring the table top attenuation with ionization chambers.Also, evaluation of dosimetric impact for VMAT prostate cancer treatments was done by different measurements: point dose measurements and gamma analysis. After measurement, the analysis estimated the clinical impact of couch attenuation, by analysing dose distribution calculated with and without taking into account couch attenuation. For 6 MV photons VMAT were observed dose differences up to 2% induced by table top attenuation. All the data extracted from measurements were used to create iBEAM evo couch model for Monaco treatment planning system, in order to be able to take into account couch attenuation during treatment planning process. |
| P: 50 | Davide Regaldo | Multi Electrode Arrays (MEA) to study neuronal networks |
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Multi Electrode Arrays (MEA) to study neuronal networksDavide RegaldoUniversità degli studi di Torino Biophysics Abstract The improvements on the technology of multi electrode arrays (MEA) of the past years have made possibile to analyze the activity of substantia nigra neuronal cells, which are subject to neurodegenerative diseases, such as Parkinson. This technique is able to measure single spikes on young cells, and bursts on older and more structured neuronal networks. Thanks to MEA it is possible to study pharmacological effects of L-Dopa or Sulpiride. |
| P: 51 | Maja Čičić | Diatoms and Drowning – Application of Scanning Electron Microscopy in Forensic Science |
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Diatoms and Drowning – Application of Scanning Electron Microscopy in Forensic ScienceMaja ČičićUniversity of Rijeka, Department of Physics Physics, Biology, Forensic Science Abstract The Scanning Electron Microscope (SEM) is used for observation and characterization of organic and inorganic surfaces on a nanometer to micrometer scale. A fine electron beam irradiates the surface of a chosen specimen and produces different types of signals that are converted into electric signals used to obtain images of the specimen surface. In suspected deaths by drowning, the specimen - femoral bone marrow - is scanned for presence of diatoms, unicellular microorganisms commonly found in water bodies. Due to their great variety, the diatoms are a sort of microbial fingerprints of the place (site specific diatoms) and the time (season specific diatoms) the drowning occurred. |
| P: 52 | Márton Pesztránszki | Interaction of silicon nanostructures in the nervous system. |
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Interaction of silicon nanostructures in the nervous system.Márton PesztránszkiEötvös Loránd University Biophysics Abstract The neural interface technologies are currently in the early phase of clinical trials to help patients with spinal cord injuries, degenerative disorders, or limb amputations. Their lifetime is of key importance. The life of these devices depends on their biocompatibility. We tested an implanted black polySi nanostructured surfaces and compared to microstructured Si surfaces in an eight week in vivo experimment. The in vivo experiments are far more complex than the widely used in vitro model systems. So far, only a few studies can be found in the literature, where the effect of nanostructured surfaces was characterised in vivo, and even less where long-term tissue responses were also investigated. |
| P: 53 | Anders Frederiksen | Fibronectins' adhesion to graphene |
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Fibronectins' adhesion to grapheneAnders FrederiksenUniversity Of Southern Denmark Computational Biophysics Abstract Fibrononectin (FN) is a large protein complex in the human stem cell which is part of cell adhesion, growth migration and differentiation. It is also believed to play a major role in wound healing and embryonic development. FN type III is the part of FN which codes for binding to other materials such as Integrin or, as done in this project, graphene. Studying the binding between graphene and Fibronectin is interesting as it can lead to cell growth outside the human body, which could have major applications within the medical science. As Fibronectin is a protein, understanding the interaction between amino acids and graphene is obvious as Fibronectin, just like every other protein, consists of amino acids. The study of the interaction between amino acids and graphene can be made into small systems, opening up the possibilities for Quantum chemical simulations. Both the Fibronectin-graphene interaction and amino acid-graphene interactions has been studied using computational programs such as NAMD and Gaussian for the Classical Molecular Dynamics simulations and Quantum Chemical simulations respectively. |
| P: 54 | Antti Mikkonen | Intravascular Quantitative Photoacoustic Tomography |
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Intravascular Quantitative Photoacoustic TomographyAntti MikkonenUniversity of Eastern Finland Computational Physics, Medical Physics Abstract Quantitative photoacoustic tomography (QPAT) is an emerging method for medical imaging. The aim of QPAT is to estimate absorption and scattering coefficients of light in a medium based on initial pressure distribution caused by attenuation of a near-infrared nanosecond-scale laser pulse. In this work this problem is considered in an intravascular imaging situation, i.e. the medium is illuminated internally. This increases the ill-posedness of the reconstruction problem. The inverse problem is solved using the Bayesian approach with various prior distributions. The light propagation is modeled using the diffusion approximation of radiative transfer equation, which is accurate for light propagation in biological tissues. The resulting time-independent diffusion equation was solved using finite element method. Results of simulations will be shown. |
| P: 55 | Clemens Stilianu | Connection of organic semiconductors with neurons |
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Connection of organic semiconductors with neuronsClemens StilianuTU Graz Biophysics Abstract Recently, we have generated and used the semiconductor quinacridone, structured in 3D and 10 μm in size, to stimulate single cell signaling (Sytnyk et al., Nature Communications, 2017). Excitation of these quinacridone structures by short green laser pulses resulted in a fast heat response causing depolarizing currents in the attached cell. Here, we evaluate electrically excitable single cell models to induce action potentials by light stimulated organic pigment semiconductors. We use HL-1 cells, a cardiac muscle cell line that contracts and retains action potential firing similar to adult cardiomyocytes. Additionally, primary cultured murine or guinea pig heart muscle cells are as well investigated several hours or one day after extraction. Moreover, primary hippocampus neurons from new born or adult rats are prepared and evaluated. These different excitable cell types are seeded on organic pigment semiconductor devices and evaluated for action potential firing using the whole-cell patch-clamp technique. We will discuss current injection and generated membrane voltage dynamics by light stimuli. Moreover, we will further discuss alternative device designs based on engineered organic photocapacitive p-n structures. |
| Friday August 10th. | |||
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| Harald Herlin Learning Centre, Johanna workshop room | |||
| 16.45 | Karima El Azhary | Improving Energy efficiency and thermal comfort of building located in the poor areas using ecological construction materials |
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Improving Energy efficiency and thermal comfort of building located in the poor areas using ecological construction materialsKarima El Azhary, Najma Laaroussi, Mohamed GaroumField: Energy and physics Abstract The building sector is the second largest energy-consuming sector after transportation with 28% of final global energy consumption. This sector accounts more than 25% of the country's total energy consumption, of which 18% is residential and 7% is tertiary. In addition, energy consumption in this sector is growing steadily in line with the rapid evolution of the housing stock. The building sector therefore represents a significant potential in terms of rationalization of energy consumption and therefore a significant source of greenhouse gas emissions reduction. On the other hand, the unfired clay bricks offer a cost-effective form of construction and are selected for their low environmental impact. In order to valorize this ecological material in building efficiency energy and ensuring a good energy efficiency in the area where the climatic conditions are hard and the population is often poor, we proceed in this work to develop the ecological insulation of unfired clay building materials. Serval of experimental measurements of unfired clay thermal properties had been performed in order to determine the thermal diffusivity and the thermal conductivity using the Flash method and the hot plate respectively. A dynamic thermal simulation was applicated to a building located in Sahara region using unfired clay material, so as to study its impact on the energy performances, the energy needs and the thermal comfort of occupants. |
| Sunday August 12th | |||
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| New Student House, Wilhelmsson Hall | |||
| 10.15 - 12.00 | Sam Henry | Precision Magnetometry for Particle and Geophysics |
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Precision Magnetometry for Particle and GeophysicsSam HenryField: Particle Physics / Geophysics Abstract Instrumentation to track magnetic fields to high precision is an essential requirement for fundamental physics experiments aiming to search for new phenomena beyond the standard model of particle physics through measuring particle properties such as the electric dipole moment of the neutron or the muon magnetic g-2 factor. Fluctuations in low magnetic fields can be tracked using SQUIDs. Absolute measurements of high magnetic fields require atomic magnetometry. This technology also finds applications in geophysics projects seeking to understand the origin of geomagnetic phenomena, and monitor the underground medium using magnetic fields. |
| Katriina Juva | Life in the abyss – study of cold-water corals |
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Life in the abyss – study of cold-water coralsKatriina JuvaField: Geophysics/ Physical oceanography/Biophysics Abstract When thinking of ecosystem hotspots, the rainforests and their oceanic counterparts tropical coral reefs come easily in mind. However, out of sight, the ocean floor is also full of life and it is concentrated in cold-water coral reefs in depths beyond the sunlight. These reefs are out of reach to be studied with satellite remote sensing used for atmospheric or sea surface studies so in order to understand these ecosystems we rely on the model studies, lab experiments and in-situ measurements. This presentation gives a short introduction to these benthic ecosystem and the in-situ physical oceanographic experiments involved to study those areas. | |
| Elias Rabel | Interoperability of Fortran and Python – Merging old and new |
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Interoperability of Fortran and Python – Merging old and newElias RabelField: Computational Physics, Scientific Software Development Abstract Over decades FORTRAN has been the dominating programming language in scientific software development. Recently Python has become a popular programming language choice among scientists, allowing a faster rate of development and experimentation. Several solutions exist for using Fortran from within Python. However, embedding a large, existing Fortran code within a Python program can be a challenging task. I will present a new open source library, forpy, which also offers interoperability in the other direction - using Python in Fortran. Another advantage of this approach is that popular Python packages, e. g. from the fields of data science and machine learning are now available to Fortran programmers. | |
| Robin Klaassen | Burn down, not out |
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Burn down, not outRobin KlaassenField: Not physics :) Abstract Chances are, someone in your personal circle (perhaps even yourself) has had or is experiencing (signs of) a burn out. The rise of this phenomenon under young people is at the very least worrying, and definitely something which needs to be addressed. In this light-hearted talk about a serious topic, we will together look for both explanation and action, and maybe even throw some physics in the mix for a truly combustible effect – because burning stuff down is a lot more fun than burning out. | |
| Sunday August 12th | |||
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| New Student House, Wilhelmsson Hall | |||
| 16.15 - 18.00 | Benjamin Fries | Modelling in energy economics |
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Modelling in energy economicsBenjamin FriesField: Energy modelling Abstract From my personal perspective gained in my career as energy modeller and physicist I will give an overview of different fields and challenges for computer modelling in energy economics. This includes energy markets, energy demand scenarios for energy efficiency policy and greenhouse gas emissions, where models are researched, developed and operated by actors in various sectors and functions, such as energy companies, governments and research community. |
| Andreea Munteanu | AERA and High-Energy Cosmic Rays |
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AERA and High-Energy Cosmic RaysAndreea MunteanuField: High-Energy Physics Abstract - | |
| Peter van Arkel | A physicist's perspective on management consulting |
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A physicist's perspective on management consultingPeter van ArkelField: Innovation science Abstract After graduating in physics I looked for the best way to have an impact on the world and decided that management consulting for technical companies was the best for me to do this. During this presentation I will talk about my interests, my job in which I still need understanding of physics, my master thesis in which I programmed a simulation of R&D collaboration which was inspired by electrical networks and other projects I'm working on. | |
| Poster session, Sunday August 12th, 14.00-16.00 | |||
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| University of Helsinki Main Building, 2nd floor (new side) | |||
| P: 56 | Hrvoje Vrcan | No order in disorder – a Luttinger liquid story |
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No order in disorder – a Luttinger liquid storyHrvoje Vrcan, Leandra Vranješ-Markić, Henry GlydeField: Cold atoms physics Abstract Superfluidity, along with condensation, has been a recurring phenomenon in ultra-cold and low-energy systems ever since it has been discovered. This purely quantum occurrence is often described as the ability to flow without resistance. Recent studies suggest that superfluid properties of such systems can vary greatly, depending on the dimension of the system, going as far as being described by completely different theories. In this study, we turn our attention to an effectively one dimensional (1D) system of bosonic helium-4 (He) in a low-energy regime. The underlying theory describing this system is the Luttinger liquid (LL) – an effective harmonic approximation of all low-energy 1D theories with two free parameters. In particular, the focal point here is to examine whether the addition of disorder into this systems violates the theoretical predictions of the superfluid density or transfers the system into a different physical regime. To explore the properties of this system, we used a computational method called path integral Monte Carlo (PIMC), which incorporates R. Feynman’s path integral formulation of quantum mechanics into stochastic Monte Carlo simulations. As a model of a 1D low-energy system, we placed an ensemble of low but finite temperature He atoms in a cylindrical cavity (nanopore) of very narrow radius. The disorder is added as foreign particles scattered around the nanopore surface. The LL predictions for this system specify a region of physical parameters that support the existence of robust superfluidity as a topological phenomenon. Along with this, out study will review the apparent shift from this regime into spinodal decomposition, an insulating Bose glass (BG) phase, or the unknown, as well as the supposed disagreement with the theoretical predictions. |
| P: 57 | D. E. Dogaru | Topological entities in perovskite oxides |
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Topological entities in perovskite oxidesD. E. Dogaru, M. Yang, M. AlexeField: Solid State Physics Abstract - |
| P: 58 | <Elias Rabel | Interoperability of Fortran and Python - Merging old and new |
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Interoperability of Fortran and Python - Merging old and newElias RabelField: Innovation science Abstract Over decades FORTRAN has been the dominating programming language in scientific software development. Recently Python has become a popular programming language choice among scientists, allowing a faster rate of development and experimentation. Several solutions exist for using Fortran from within Python. However, embedding a large, existing Fortran code within a Python program can be a challenging task. I will present a new open source library, forpy, which also offers interoperability in the other direction - using Python in Fortran. Another advantage of this approach is that popular Python packages, e. g. from the fields of data science and machine learning are now available to Fortran programmers. |