Theoretical Physics News & Views

Publikacija "A high-temperature quantum spin liquid with polaron spins" v prestižni reviji: Sodelavci Instituta »Jožef Stefan« in Fakultete za matematiko in fiziko Univerze v Ljubljani Martin Klanjšek, Andrej Zorko, Rok Žitko, Jernej Mravlje, Zvonko Jagličić, Peter Prelovšek, Dragan Mihailović in Denis Arčon so v članku, objavljenem v prestižni reviji Nature Physics, poročali o odkritju kvantne spinske tekočine v plastovitem kristalu TaS2. S tem so razrešili skrivnost magnetnega stanja v tem pomembnem modelskem sistemu, ki je begala raziskovalce že več kot 40 let. Pri tem stanju je še posebej zanimivo to, da kaže prepletenost na daljavo - z drugimi besedami, je makroskopsko kvantno stanje, podobno kot superprevodnost. To odkritje odpira povsem nove priložnosti za razumevanje tega enigmatičnega magnetnega stanja in za razvoj novih kvantnih tehnologij. Read more Nature Physics
Dr Luka Leskovec received Golden Emblem Prize (Zlati Znak Jožefa Stefana) for his Ph.D. Thesis "Hadronic resonances in Lattice QCD (Hadronske resonance v kromodinamiki na mreži)" The research work in his Thesis was completed at the Department of Theoretical Physics under supervision of Assistant Prof Dr Saša Prelovšek Komelj and has already achieved over 500 citations. The justification of the prize states that Luka Leskovec and collaborators performed the first ab-initio theoretical study of the hadronic resonances that contain strange or charm quarks. Moreover, a method for rigorous study of mesons slightly threshold was developed and applied for the first time. The results of his challenging lattice simulations show good agreement with experimental results and shed new light on them. Read more about the Jožef Stefan Golden Emblem Prize and the Prize Winners---Dobitniki Zlatih Znakov Jožefa Stefana 2017.
Professor Janez Bonča presents "Počasni posnetek elektronske kvantne dinamike" (Slow snapshot of the electronic quantum dynamics) the research based on the publication Snapshots of the retarded interaction of charge carriers with ultrafast fluctuations in cuprates, Nature Physics Vol 11, 421 (2015) co-authored by Prof Janez Bonca, Dr Lev Vidmar and Dr Denis Golež from The Department of Theoretical Physics, which has been selected within the initiative by Odlicni v znanosti 2016-naravoslovje (Excellent in the science 2016-natural sciences) by The Research Agency of The Republic of Slovenia initiative for promotion of science. Read more about the event....
Assistant Prof Dr Jernej Fesel Kamenik received Zois Distinction for important achievements in research of new physics in the theory of elementary particles The Committee recognises Dr Jernej Fesel Kamenik as one of the world's most successful and most insightful young physicists and one of the few theoretical physicists reacting extremely quickly to new experiments in particle physics. His contribution to the potential interpretations of the experimental data that indicate the possible existence of a previously unknown elementary particles, the international scientific community highly appreciates. In recent years, based on some of the surprising results of experiments with elementary particles, he gave the interpretation of signals and predictions and proposed new measurements, which have been cited more than 1500 times in the scientific literature. link to the official site: doc. dr. Jernej Fesel Kamenik je prejel Zoisovo priznanje za pomembne dosežke iskanja nove fizike v teoriji osnovnih delcev.
A computational model predicts mechanical properties associated with tissue behavior in Drosophila Gastrulation is an early stage in embryonic development of Drosophila. During this developmental process, tissue on the embryo’s ventral side is invaginated and forms a ventral furrow in the paper by Matteo Rauzi, Uros Krzic, Timothy E. Saunders, Matej Krajnc, Primoz Ziherl, Lars Hufnagel & Maria Leptin. The authors use multi view selective plane illumination microscopy to study the deformational pattern of the entire embryo during gastrulation. The experiments both on wildtype and mutant embryos show that the tissue consists of three cell populations which behave differently. They propose a theoretical model where the deformational pattern is determined by the differential cortical tensions of the three cell populations and show that the very well coordinated cell movements and collective deformation of the entire embryo during ventral furrow formation results only from the fact that different cell populations have different elastic properties. Read more Nature Communications 6, 8677 doi:10.1038/ncomms9677.
Processes of knowledge creation in online social interactions as a physics problem A wealth of data from online social systems in recent years provided the opportunity to study the underlying social processes by means of quantitative sciences. Nevertheless, the processes in which social value emerges, such as the creation of the collective knowledge, remained a challenging problem to physics and social dynamics modeling. In the recent paper, M. Mitrovic Dankulov, R. Melnik, B. Tadic, The dynamics of meaningful social interactions and the emergence of collective knowledge Sci. Reports 5, 12197 doi:10.1038/srep12197, the authors develop an approach based on the idea of multiscale dynamics in physical systems. The approach couples Nonequilibrium Statistical Physics and Graph Theory together with Methods of Information Theory. The methodology, applied to the empirical data of Q&A from Mathematics jointly with the Agent-Based Simulations, successfully explains the interplay of the human dynamics and the cognitive contents from the microscopic to a global scale and quantifies the emergence of social communities that use the accumulated knowledge. Read more in
Jozef Stefan Institute's Scientist Emeritus Rasa Pirc elected Full Member of The Slovenian Academy of Sciences and Arts
On 18 June 2015, The Academy promoted Full Members: in Section for Historical and Social Sciences Acad. Peter Štih, Mathematical, Physical, Chemical and Engineering Sciences Acad. Raša Pirc, Natural Sciences Acad. Tatjana Avšič-Županc and Acad. Bostjan Kiauta, and Medical Sciences Acad. Bojan Čerček and Acad. Janez Lamovec. Read the original (Slovenski text...).
Physical Review E: Kaleidoscope for May 2015 shows this picture from our paper Hidden geometry of traffic jamming, authors M. Andjelkovic, N. Gupte, B. Tadic from The Department of Theoretical Physics. The picture shows a close-up of the mathematical graph representing the complexity of connections among the states of a traffic problem on networks. Full topology analysis of the phase space manifolds near the jamming transition is performed using the techniques of Algebraic topology of graphs. Read more in the paper Phys. Rev. E 91, 052817....
Particle Phenomenology From the Early Universe to High Energy Colliders International conference organized by B. Bajc, S. Fajfer (chair), J.F. Kamenik, N. Kosnik, and M. Nemevsek from The Department of Theoretical Physics. The primary goal of the third in the series of workshops is to discuss complementary aspects of elementary particle phenomenology both within the standard model and beyond: those relevant for the second run of the Large Hadron Collider and possible future high energy colliders; in high intensity experiments, measuring quark/lepton number, flavour and CP violation; in astroparticle experiments probing the matter content of the universe. Planned topics to be covered include Higgs boson and electroweak physics, top quark physics, flavour phenomena and CP violation, neutrino physics, dark matter as well as other particle dynamics in the early universe. source page: Portoroz 2015
The retarded interaction of charge carriers with ultrafast fluctuations in cuprates In a recently published article in Nature Physics prof. J. Bonca from the Department of Theoretical Physics, together with his former PhD students dr. L. Vidmar and dr. D. Golez in collaboration with the experimental group from Italy addressed one of the pivotal questions in the physics of high-temperature superconductors concerning the question whether the low-energy dynamics of the charge carriers is mediated by bosons with a characteristic timescale. This issue has remained elusive as electronic correlations are expected to greatly accelerate the electron-boson scattering processes, confining them to the very femtosecond timescale that is hard to access even with state-of-the-art ultrafast techniques. The experimentally observed timescale is in agreement with numerical calculations on a model in which the relaxation of the photo-excited charges is achieved via inelastic scattering with short-range antiferromagnetic excitations. Journal source...;(Slovenski tekst....)