4th Users' Conference of IT4Innovations

Thursday 5 Nov 2020, 09:00 → 12:40 Europe/Prague

ONLINE (IT4Innovations)

4th Users' Conference of IT4Innovations will take place on November 5, 2020 and will be fully virtual. All of our users as well as research and project partners from various organisations, research institutions and industry are welcome to attend the conference.

Registration is open until November 2, 2020.

Attendees will discover more about our future upgrade plans, listen to talks given by our prominent users and can engage in discussions during the Users' Council meeting and the poster session.

Contribution types: 

Keynotes

Selected talks by our prominent users will be presented at scheduled times during the conference. Each keynote is expected to take max. 20 mins (with discussion included).

Posters

All posters will be published at the conference website.

The link for the conference will be send via e-mail on November 2, 2020 to registered participants only.

Poster Session

• Bidlo_Michal_Advances_in_the_Evolutionary_Design_of_Complex_Cellular_Automata.pdf
• Brezina_Interplay of planar defects and chemical disorder within Bi2Se3 topological insulator.pdf
• Cernekova_Michaela_Structural_and_Simulation_Analysis_of_Ribosomal_Tunnel_Proteins.pdf
• Cervinka_Interpretation of phase behavior of ionic liquids using the tool of theoretical chemistry.pdf
• Cigarini_Understanding the lattice dynamics of multilayered h-BN- peculiar infrared optical responses.pdf
• Erlebach_Accurate modeling of zeolite (in-)stability using tailored neural network potentials.pdf
• Fraile_Alberto_Hypervelocity_impacts;_W_on_W_using_Molecular_Dynamics.pdf
• Istokskaia_Valeria_Verification_of_Unfolding_Technique_developed_for_a_Scintillator-Based_Calorimeter´s_Signal_.pdf
• Kadzielawa_Inhibition of steel corrosion with imidazolium-based compounds.pdf
• Kostal_SOLVENT-INDUCED STABILITY OF THE BENZENE RADICAL ANION.pdf
• Matys_Martin_Generation_of_collimated_quasi-monoenergetic_proton.pdf
• Nikl_Multi-dimensional magneto-hydrodynamic code based on curvilinear finite elements.pdf
• Sebesta_Interplay of planar defects and chemical disorder within Bi2Se3 topological insulator.pdf
• Sestak_Peierls-Nabarro model of dislocations and its applications to magnetic shape memory alloys.pdf
• Sethia_Svobodova_Strakos_Tool_for_Medical_Data_Processing_and_3D_Model_Reconstruction_of_Tissue_in_Blender.pdf
• Valenta_Petr_Relativistic_Mirrors_as_a_Compact_Source_of_Coherent_Short-Wavelength_Radiation.pdf
• Velimsky_3-D INVERSION OF MANTLE ELECTRICAL CONDUCTIVITY USING M2 OCEAN TIDES.pdf
• Vymola_Legut_Use of Singularity containers on IT4I systems from the perspective of normal user.pdf
• Zadrazil_Heyda_Prominent pathways of hydrophobic polymer collapse.pdf
• Zemen_Jan_MAGNETIC STRUCTURE AT PEROVSKITE:ANTIPEROVSKITE INTERFACE.pdf

Introduction to the latest advances at IT4Innovations

Introduction to the latest advances at IT4Innovations towards the users of the IT4I systems (new technologies, software, LUMI, EuroCC, etc.)

Conveners: Branislav Jansik (IT4Innovations), Vít Vondrak (IT4Innovations, VSB-Technical University of Ostrava)

Users' Council

Convener: Branislav Jansik (IT4Innovations)

11:00 Coffee Break

Keynote: Lattice vibrations and the trimerons order of magnetite at Verwey transition

Convener: Dominik Legut (IT4I)

1 Lattice vibrations and the trimerons order of magnetite at Verwey transition

In this talk we shed a light on hidden quantum properties in magnetite, the oldest magnetic material known to mankind. The study reveals the existence of low-energy waves that indicate the important role of electronic interactions with the crystal lattice as well as the lattice vibrations in both high-temperature cubic as well low-temperature monoclinic phases. This is another step to fully understand the metal-insulator phase transition mechanism in magnetite, and in particular to learn about the dynamical properties and critical behavior of this material in the vicinity of the transition temperature. The attentions of physicists in magnetite was attracted by a fact that at temperature of 125 K it shows an exotic phase transition, named after the Dutch chemist Verwey. This Verwey transition was also the first phase metal-to-insulator transformation observed historically. During this extremely complex process, the electrical conductivity changes by as much as two orders of magnitude and a rearrangement of the crystal structure takes place. Verwey proposed a transformation mechanism based on the location of electrons on iron ions, which leads to the appearance of a periodic spatial distribution of Fe2+ and Fe3+ charges at low temperatures as well as the orbital order. In this talk we confirm the fundamental components of this charge-orbital ordering are polarons – quasiparticles formed as a result of a local deformation of the crystal lattice caused by the electrostatic interaction of a charged particle (electron or hole) moving in the crystal. In the case of magnetite, the polarons take the form of trimerons, complexes made of three iron ions, where the inner atom has more electrons than the two outer atoms. Our study reveals a very accurate model of lattice vibrations for the high temperature phase as well as confirm the effect of the charge-orbital (trimeron) order on phonon energies and mean square displacements in the monoclinic(low-temperature) phase and hence to contribute to shed a light at the complexity of the Verwey transition. The work was published [1-3] and acknowledges Path to Exascale project, No. CZ.02.1.01/0.0/0.0/16_013/0001791 within the Operational Programme Research, Development and Education.
References:
[1] E. Baldini , C.A.. Belvin, M. Rodriguez-Vega, I. O. Ozel, D. Legut, A. Kozłowski, A. M. Oleś, K.Parlinski, P. Piekarz, J. Lorenzana, G. A. Fiete, and N. Gedik, Discovery of the soft electronic modes of the trimeron order in magnetite, Nature Physics 16, 541 (2020).
[2] S. Borroni, E. Baldini, V. M. Katukuri, A. Mann, K. Parlinski, D. Legut, C. Arrell, F. van Mourik, J. Teyssier, A. Kozlowski, P. Piekarz, O. V. Yazyev, A. M. Oleś, J. Lorenzana, and F. Carbone, Coherent generation of symmetry-forbidden phonons by light-induced electron-phonon interactions in magnetite Phys. Rev. B 96, 104308 (2017).
[3] P. Piekarz, D. Legut, E. Baldini, C. A. Belvin, T. Kolodziej, W. Tabi,A. Kozlowski, Z. Kakol, Z. Tarnawski, J. Lorenzana, N. Gedik,
A. M. Olés, J. M. Honig, and K. Parlinski, Trimeron-phonon coupling in magnetite, subm. to Phys. Rev. B (September 2020)

Speaker: Dominik Legut (IT4I)

Keynote: Precision in ab initio calculations

Convener: Jiri Klimes (Faculty of Mathematics and Physics, Charles University)

2 Precision in ab initio calculations

Computer simulations of materials have been immensely useful for understanding processes at the atomic and molecular levels. The ability to 'see' atoms moving during reaction or dynamics is exciting and useful to understand experimental observations. However, one should not forget that a range of approximations is needed to be able to perform such a simulation. For quantum simulation of molecules and materials one usually things first about the accuracy -- approximations of Hamiltonian and wavefunction. Less severe approximations give more accurate results but usually require substantially more computational resources compared to more approximate methods. However, computer simulations also require approximations to numerical set-up, such as introducing a real-space grid or basis functions to represent continuous functions. Using coarser grid or less functions speeds-up the calculations but can lead to a substantial loss of precision, sometimes changing the results qualitatively. I will discuss two examples of issues concerning precision. First, many simulations of materials use pseudopotentials or similar methods, such as the projector-augmented wave (PAW) scheme, to avoid the calculation of tightly-bound core electrons. Typically, different PAW datasets are available for every element, more precise hard or less precise soft allowing much faster calculations. We have analyzed the errors of different PAW datasets by comparing to binding curves of molecules calculated with reference all-electron set-up. Our goal is not only to evaluate the errors but also understand how much are the errors transferable, that is, if a simple scheme could be used to correct the results obtained with the less precise datasets. Second, I will discuss an interesting class of molecular solids, called co-crystals, which are formed by two, or more, components. There are co-crystals with strong hydrogen bonds between the individual molecules. In some cases the hydrogen can transfer from one molecule to the other so that a salt is formed. While one needs accurate methods to correctly describe if the hydrogen will transfer or not, the process is also very sensitive to the precision of the computational set-up. I will show examples where choosing too cheap set-up qualitatively changes the results and how this can be avoided.

Speaker: Jiri Klimes (Faculty of Mathematics and Physics, Charles University)

Keynote: Multiple Stellar Generations Within Globular Clusters

Convener: Michalis Kourniotis (Astronomical Institute, Czech Academy of Sciences)

3 Multiple Stellar Generations Within Globular Clusters

Globular clusters are spheroidal and dense collections of stars with a total mass of up to a few million solar masses that are typically found in the halo of our galaxy and of other galaxies. Their formation dates back to the early Universe and so, they serve as laboratories for understanding the physical processes that chemically enrich and mechanically shape the interstellar medium throughout the history. Observations of globular clusters in the Galaxy show that such clusters frequently host multiple generations of stars being characterized by different age and chemical composition. Thanks to the development of parallelized hydrodynamic simulations, such diversity is now well interpreted in the context of stellar feedback. The powerful winds and radiation from the older stellar content of the cluster is shown to induce thermal instabilities, which lead to accumulation of gas in the interior. Such clumps of gas are self-shielded against the ionizing photons and, when dense enough, they can serve as the primordial material of the posterior stellar generations.

In an effort to capture the dynamical processes that lead to multiple stellar generations within globular clusters, we focused on the properties of five such clusters in the Galaxy. We employed the parallelized three-dimensional FLASH4 hydrodynamic code to simulate the gas dynamic and thermal instabilities. Alongside, we are developing modules that, at each timestep, optimally describe the gas properties, the radiation field, the gravitational forces, and cooling processes of the gas, as well as the formation and dynamics of the clump particles. The ionizing photons, mass, and energy of the stellar winds, collectively regarded as the stellar feedback, were provided by our stellar population synthesis code that is fed with the state-of-the-art models of massive star evolution. Moreover, high energetic sources such as supernovae that occur at the end of the massive star lifetime were further accounted, given that their high mass-loss output via strong ejecta provide significant energy deposit to the medium of the cluster.

Our simulations were run in parallel over ~100 cores per run on the Salomon supercomputer, which is installed on the IT4Innovations National Supercomputing Center. A total of ~700,000 allocated core hours was used for exploring different sets of input parameters and over different resolutions of the computational grid in order to resolve the clumps and capture gas structures. We were able to reproduce the ratio and therefore justify the origin of the diverse generations observed within our studied clusters by means of the in-situ star formation due to dynamical stellar feedback. In addition, we derived an excellent agreement between the stellar mass yield that is inferred by our 3D simulations and the output from our one-dimensional semi-analytical code establishing the latter method as a fast and computationally inexpensive way for quantifying the stellar mass budget.

Speaker: Dr Michalis Kourniotis (Astronomical Institute of Czech Academy of Sciences)

Keynote: Research and development of an input data generator for obstacle detection training in simulated environment

Convener: Petr Strakos (IT4Innovations)

4 Research and development of an input data generator for obstacle detection training in simulated environment

We cooperate with IXPERTA s.r.o. company in the development of a software simulator capable of generating the training data for creation of an obstacle detection system used in a railway vehicle. The project is supported by Technology Agency of the Czech Republic (TACR), in the program of industrial research and experimental development TREND and ends in 2022.
The simulator will allow to create a virtual 3D environment of a railway track as a virtual replica of a real track. Together with this, acquisition of various sensors’ output from the simulated environment will be available. This includes RGB camera, LIDAR, thermal camera etc., which will try to mimic their real counterparts mounted on a railway vehicle.
In the virtual environment, it will be possible to simulate multiple critical scenarios that might arise on a real track. Besides, it will be possible to mimic different weather conditions such as rain, snow, fog and influence the generated output data. The simulator will therefore provide virtualization of a railway track conditions and it will carry out test runs in a laboratory environment.
As a part of the simulator development, it is necessary to specify a set of scenarios that can occur and select parameters of the virtual environment that can be influenced. In this way simulator’s complexity will be limited while also ensuring required variability and quality of the output data to fulfil the training of the obstacle detection system. To provide high quality of the generated data we utilize ray tracing as a rendering method. Due to the computational complexity, we perform rendering on the IT4Innovations’ infrastructure.
In our contribution we will describe our goals in more detail, and we will present our actual progress in the project.

Speakers: Petr Strakoš (IT4Innovations), Alena Ješko