У оквиру СЦЛ семинара Центра за изучавање комплексних система, у четвртак, 12. јула 2018. у 14 часова у читаоници библиотеке „Др Драган Поповић“ Института за физику у Београду, др Марко Младеновић (Laboratory for Computational Chemistry and Biochemistry, EPFL, Switzerland and Scientific Computing Laboratory, Center for the Study of Complex Systems, Institute of Physics Belgrade) ће одржати предавање:

First-principles calculations of materials for photovoltaic applications

САЖЕТАК:

Halide perovskites attracted strong interest during the last decade due to excellent electronic and transport properties that are essential for photovoltaic applications. After a brief introduction to halide perovskites, we will present studies on band gap tuning and effective masses characterization in these compounds. Secondly, we will explain unusual band gap dependence in lead-tin halides. Parallel to efforts to improve properties of lead-based perovskites, researchers also look for lead-free alternatives. Class of compounds that recently gained interest are silver bismuth iodides. Despite their promising photovoltaic characteristics, our theoretical study shows that silver bismuth iodides have intrinsic limitations, such as weaker transport properties and higher exciton-binding energies in comparison to halide perovskites. Finally, we will briefly present our ongoing investigations of electronic properties of the perovskite-TiO2 interface, NMR chemical shifts calculations and polaron formation in halide perovskites.

У оквиру СЦЛ семинара Центра за изучавање комплексних система, у понедељак, 9. јула 2018. у 14 часова у читаоници библиотеке „Др Драган Поповић“ Института за физику у Београду, др Нилс Винцел (Institute for Theoretical Physics – IPhT, CEA Saclay, France) ће одржати предавање:

Containerization in modern scientific applications

САЖЕТАК:

Scientific algorithms for the solution of the correlated many-body problem and beyond are rapidly growing in complexity. This development shows also in their respective numerical implementations, leading to growing number of library dependencies, toolchain dependencies and further interdependencies with other scientific applications. This often makes a proper setup on workstations, but in particular on high-performance cluster machines, an ambitious and sometimes insurmountable task. In this talk, we will give a practical introduction into modern containerization tools, in particular Docker and Singularity, which aim to overcome these issues. As an example application, we will consider the TRIQS library, a Toolbox for Research on Interacting Quantum Systems.

У оквиру Семинара Групе за честице и гравитацију, у петак 6. јула у 11 часова на Институту за физику у Београду у сали 360, др Марко Војиновић ће одржати предавање:

„Canonical structure of the 2-BF theory for the Poincare 2-group“

САЖЕТАК:

We perform the full Hamiltonian analysis of the topological BFCG action based on the Poincare 2-group. The Hamiltonian of the theory is constructed, and the algebra of constraints is computed. The Dirac brackets are evaluated, and the second class constraints are then eliminated from the theory. The results are contrasted to those of the topological Poincare gauge theory, which is equivalent to the BFCG model at the level of the classical action, but has a very different Hamiltonian structure. The canonical transformation which maps between the two theories turns out to be singular in a certain sense.

У оквиру СЦЛ семинара Центра за изучавање комплексних система, у четвртак, 5. јула 2018. у 14 часова у читаоници библиотеке „Др Драган Поповић“ Института за физику у Београду, др Јакша Вучичевић (Лабораторија за примену рачунара у науци, СЦЛ, Центар за изучавање комплексних система, Институт за физику у Београду) ће одржати предавање:

Lattice Model Database (LMDB)

САЖЕТАК:

Aggregate analyses of large computational datasets have recently proven very useful in predicting novel functional materials [1, 2]. However, when it comes to strongly correlated lattice models like Hubbard, Anderson, Heisenberg etc., there is currently no systematic way of automatizing analyses of the huge body of numerical results already published in the literature. In this hands-on presentation, we will demonstrate the capabilities of LMDB, the newly developed peer-to-peer numerical-result-sharing system, aimed at mediating collaborations and systematizing the collective knowledge of lattice model physics. The fully formal structure of the database and the associated API which is abstracted from data formats, filenames and locations, allow for automatized searches and analyses. Additionally, the database features a simple graphical user interface for plotting data from multiple remote sources, as well as manipulating own data and generating new results using shared codes.

[1] H. C. Harper et al., Phys. Rev. Materials 1, 033802 (2017).
[2] W. Sun et al., Nanoscale, 8, 15753-15762 (2016).

У оквиру традиционалног колоквијума Института за физику у Београду, у уторак, 3. јула 2018. у 12 часова у сали „Звонко Марић“ проф. др Матијас Шот (Institute of Physics, Johannes Gutenberg University Mainz, Germany) ће одржати предавање:

Light-by-light scattering at the LHC and the search for axion-like particles

САЖЕТАК:

Light-by-light scattering is a quantum-mechanical process that is forbidden in the classical theory of electrodynamics, but was predicted already more than 70 years ago by Heisenberg and Euler. This reaction is accessible at the Large Hadron Collider (LHC) thanks to the large electromagnetic field strengths generated by ultra-relativistic colliding lead ions. Using 480 μb^-1 of lead–lead collision data, recorded at a center-of-mass energy per nucleon pair of 5.02 TeV by the ATLAS detector, a first evidence for light-by-light scattering in collisions was found. In this talk, we will review the experimental setup and the corresponding data-analysis with a special focus on potential systematic and theoretical uncertainties. Moreover, we will give an outlook on possible searches for axion-like particles using this reaction, as well as in proton-proton collisions in general.

У петак 22. јуна 2018. у 11 часова на Институту за физику у Београду у читаоници ,,Др Драган Поповић“ наш колега др Бранислав Цветковић, руководилац Групе за гравитацију, честице и поља, одржаће семинар под насловом:

,,Општа Поенкареова локална теорија: Хамилтонова структура и честични спектар“

САЖЕТАК:

Размотрени су основни аспекти Хамилтонове структуре локалне Поенкареове теорије која нарушава парност. Одређене су све могуће примарне везе, идентификовани критични параметри и конструисан канонски Хамилтонијан у генеричком случају. Осим што су сами по себи значајни, ови резултати обезбеђују важне информације неопходне за разумевање честичног спектра теорије израчунатог у апроксимацији слабог поља око простора Минковског.