Projects / Programmes
Solid state theory and statistical physics
January 1, 2022
- December 31, 2027
| Code |
Science |
Field |
Subfield |
| 1.02.00 |
Natural sciences and mathematics |
Physics |
|
| 1.07.00 |
Natural sciences and mathematics |
Computer intensive methods and applications |
|
| Code |
Science |
Field |
| 1.03 |
Natural Sciences |
Physical sciences |
quantum many-body systems, transport properties, strongly correlated systems, frustrated systems, electron-phonon coupling, nonequilibrium dynamics, eigenstate thermalization, ergodicity breaking, pump-probe spectroscopy, engineered quantum systems, topological states, self-organized criticality
Data for the last 5 years (citations for the last 10 years) on
April 24, 2024;
A3 for period
2018-2022
| Database |
Linked records |
Citations |
Pure citations |
Average pure citations |
| WoS |
687 |
18,871 |
15,939 |
23.2 |
| Scopus |
688 |
19,653 |
16,679 |
24.24 |
Researchers (27)
Organisations (2)
Abstract
The programme is devoted to the theory of solid-state physics and complex systems. Our overarching goal is to explain and predict emergent phenomena through the development and applications of novel methodologies, especially numerical techniques. We focus on electronic and magnetic properties with a special attention to strong correlation effects due to Coulomb interaction, which are particularly challenging and require innovative numerical approaches running on high-performance computers. A common aspect underlying almost all investigations is the interest in transport properties. One can categorize research activities into four partially overlapping classes with respect to the degree of realism and the degree of departure from the equilibrium. (a) In equilibrium & fundamental class the research focuses on thermodynamic, dynamic, and transport properties of many-body systems in equilibrium. The paradigmatic systems under investigation are: (i) strongly correlated systems with unconventional transport properties such as cuprate superconductors, as well as related systems; (ii) disordered systems; (iii) frustrated systems, which include quantum spin liquids, spin glasses, and systems close to a quantum phase transition. (b) In nonequilibrium & fundamental class, we investigate the mechanisms of thermalization, quantum ergodicity and many-body quantum chaos, and cases when those fail: the ergodicity breaking scenarios, the emergence of quantum integrability, and the impact of symmetries. (c) Equilibrium & realistic class is devoted to the interpretation and prediction of experimental results in full realistic detail. We are intensely collaborating with leading experimental groups, on topics of high current interest in the fields of solid-state physics, cold-atom gases, semiconductor nanodevices, engineered quantum systems, and surface science. We also focus on new rapidly developing areas such as twisted multilayer materials with extremely large unit cells and unique ground states, including unconventional superconductivity and topological states. (d) The nonequilbrium & realistic class concerns the nonequilibrium dynamics of complex quantum systems including realistic details. In pump-probe spectroscopy the key question is how to properly calculate, model and interpret the relaxation processes, in particular how to disentangle the relaxation due to different dynamic degrees of freedom: electrons, spins, and lattice. Our activities in Statistical physics of classical complex systems and networks focus on investigating nonequilibrium systems with many elements and interactions represented by nodes and edges of higher-order networks. Common to all research areas is the development and improvement of efficient numerical (and related analytical) methods to deal with quantum and classical many-body models and their static and dynamical properties.
Significance for science
The goals of the Programme are related to subjects which are at present among the most challenging and interesting within the theory of solid state and statistical physics. Theory of quantum many-body (QMB) systems which will be the main focus in the next period is a very active and wide subject ranging from fundamental questions on the interplay between quantum aspects of particles (predominantly electrons in our studies), their interactions, but also including the effects of disorder, local impurities, geometric and internal frustration, coupling to other degrees of freedom (as phonons), spin-orbit coupling and topology. The main achievement of the Programme should be the contribution to worldwide scientific efforts to understand and even quantitatively describe QMB systems and their models. In particular we plan to settle the phenomena ranging from fundamental to material-related ones: a) the basic statistical and dynamical properties of QMB systems in relation with thermalization, quantum-level statistics, quenched dynamics, disorder-induced localization and impurity effects, b) description and calculation of properties of real materials as well as related and promising physics of cold-atom systems. The main results of the Programme are expected to be publications in high-visibility journals, but also presentations in international meetings, applications and involvement in international (and domestic) projects. One of the constant efforts of the Programme members is in the development and advances of efficient numerical (and related analytical) methods to deal with QMB models and their static and dynamical properties. The methods to deal with finite-temperature static and dynamical model properties, as FTLM and MCLM, are constantly improved and already employed by various foreign groups. The locally developed NRG method for impurity problems is widely known and will be further advanced. We also expect the advance and dissemination of DMFT-based far-from-equilibrium methods. All these efforts are intimately related to usage and advances in high-performance computing for solid-state problems and technology. An important aspect of the Programme is the close collaboration with the experimentalists, working in the Institute, but also worldwide, on different aspects of QMB systems. In particular we plan to further follow experiments on novel materials with frustrated and low-dimensional quantum aspects, time-resolved spectroscopy on correlated materials and novel cold-atom experimental group.
Significance for the country
In the proposed research in the theory of quantum many-body systems we mainly address issues related to models describing new materials with unusual, potentially technologically extremely important properties. The ever-growing list of new materials offers unforeseen opportunities for technological applications in many areas of human activity (energy transfer, conversion of heath current to electrical current, design of improved high-Tc materials, anomalously large thermal conduction of certain low-dimensional insulating spin systems, etc.). Obtained results of iron electrical conductivity in Earth core in the presence of light elements have a huge impact on our understanding of the Earth magnetic field. The theoretical investigations in the field of nanosystems are of great importance for the understanding and development of new nano-devices and their potential application in e.g., medicine, public administration and affairs, households, etc. Equally important is the quantum computing and informatics, where a thorough understanding of decoherence effects is instrumental to an effective implementation of quantum computation algorithms and communication protocols based on quantum entanglement. This subject is of great importance in the field of cryptography. Another topic originates from the more general field of statistical mechanics and is devoted to the study of the complex dynamical systems and networks, a topic with a potentially large impact in a vast area of socio-economic infrastructure. 3) Potential impact on social and cultural development: Nearly all members of the Programme are involved in the education of physics subject at the University of Ljubljana at several Faculties. Three are full professors at the Faculty of Physics and Mathematics, further five are Assistant and Associate Professors having full or partial teaching load, while also younger colleagues are getting involved into University duties. So one of the goals of the Programme is to keep high level of University education and bring younger generations into contact with modern knowledge, research, science and technology. The Programme is also essential support for Ph.D. students, which perform their research and finishing their thesis under the supervision of senior Programme members. So far the Ph.D. finishing within this framework were very successful in their further careers. Some of them got prestigious postdoc positions and continued their academic careers in Slovenia or elsewhere. To attract the best young physicists and to introduce them into research remains one of the central goals of the Programme. Also, the focus of research on usage and development of computer applications also gave essential support to several young colleagues, which after finishing Ph.D. entered mostly high-technology companies. To be more concrete we list a few examples that represent a specific outreach. Former postdoc 2011-12 of the Programme dr. Robin Steinigeweg after returning to Germany became spokespeople of DFG (Deuche Forschungsgemeinschaft) Research unit and was awarded in 2020 Full Professor position at the University of Osnabrueck. Dr. Jacek Herbrych, finishing Ph.D. within the group in 2013, after postdoc positions in Greece and US, returned in 2019 to Poland receiving one of the most prestigious Polish research projects and the position at the Wroclaw University. Osor Barisic, a former postdoc within the Programme group is now a Senior research associate in the Institute of Physics Zagreb, and was in 2021 elected for the Director of the Institute. Prof. A. Ramšak was a candidate for the rector of the University of Ljubljana. While keeping pace with research at the forefront of the many topics in statistical physics and physics of the solid state, we are able to interact with research groups worldwide competitively, thus providing direct means for the enrichment of national scientific and cultural heritage. In the past research period we have organized 13 international conferences ( three in Odessa Ukraine, one in Vienna and the rest in Slovenia) while our researchers have presented invited talks on over 150 international conferences. Organization of international conferences, invited plenary talks on well recognised international conferences, citations of our work in review articles, publication of our research results in renowned journals, membership in international boards, joint EU projects and bilateral projects worldwide, all these contribute to the recognition of Slovenia as a modern European country with a well developed scientific and technological basis. Our achievements also contribute to our self-awareness and confidence as a small nation amid the global community.
