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Projects / Programmes source: ARIS

Theory of condensed matter and statistical physics

Periods
Research activity

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
P002  Natural sciences and mathematics  Physics 
Keywords
Organic and inorganic relaxor ferroelectrics, perovskite ferroelectrics, computer networks, strongly correlated electrons, high-temperature superconductors, quantum wires, surface reconstrucion, quantum chaos.
Evaluation (rules)
source: COBISS
Researchers (17)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  30219  PhD Osor Slaven Barišić  Physics  Researcher  2008 
2.  26152  Boštjan Berčič  Physics  Technical associate  2008  20 
3.  04943  PhD Janez Bonča  Physics  Head  2004 - 2008  286 
4.  22322  PhD Samir El Shawish  Energy engineering  Researcher  2004 - 2008  151 
5.  18270  PhD Kristjan Haule  Physics  Researcher  2004  69 
6.  22507  PhD Martin Horvat  Physics  Junior researcher  2004 - 2006  76 
7.  25625  PhD Jernej Mravlje  Physics  Junior researcher  2005 - 2008  132 
8.  02581  PhD Raša Matija Pirc  Physics  Researcher  2004 - 2008  295 
9.  01105  PhD Peter Prelovšek  Physics  Researcher  2004 - 2008  424 
10.  12279  PhD Tomaž Prosen  Physics  Researcher  2004 - 2008  502 
11.  04544  PhD Anton Ramšak  Computer science and informatics  Researcher  2004 - 2008  199 
12.  19162  PhD Tomaž Rejec  Physics  Researcher  2004 - 2008  69 
13.  01100  PhD Igor Sega  Physics  Researcher  2004 - 2008  69 
14.  06358  PhD Bosiljka Tadič  Physics  Researcher  2004 - 2008  368 
15.  01121  PhD Igor Vilfan  Physics  Researcher  2004 - 2008  105 
16.  24277  PhD Mihael-Matjaž Zemljič  Physics  Junior researcher  2005 - 2008 
17.  21369  PhD Marko Žnidarič  Physics  Junior researcher  2004 - 2006  149 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  91,035 
2.  1554  University of Ljubljana, Faculty of Mathematics and Physics  Ljubljana  1627007  34,301 
Abstract
We will investigate microscopic physical mechanisms which are responsible for the giant electrostriction and piezoelectric effects in organic and inorganic relaxor ferroelectrics. A model of perovskite ferrolectrics such as barium titanate will be developed, based on the off-center positions of the Ti ions and their coupling to lattice vibrations. By means of computer modeling of transport on complex networks and their topology we will make a comparative study of information traffic on technological networks and genetic regulatory networks. We will determine the parameters of transport and drivUnding conditions adjusted to optimal use of the underlying network structure. We will furthermore simulate anomalous diffusion of individual grains in cellular automata models of granular flow and spin diffusion in disordered ferroelectrics under global driving conditions. Within the research field of strongly correlated electrons, as related to theoretical modeling and understanding of material properties of new high temperature superconducting materials the efforts will be dedicated to a) the development of new numerical methods as relevant to model Hamiltonians on finite lattices, b) to the theoretical understanding of the mechanism of superconductivity in cuprate superconductors, c) to the investigation of transport properties of low-dimensional quantum systems in conjunction with the integrability of related model Hamiltonians, and d) to the study of the dynamical stability of quantum system as relevant to quantum computing. Using new numerical techniques we furthermore plan to study the problem of conductance of an interacting mesoscopic sample. This approach will be based on variational wave function calculation and the quantum Monte Carlo method applied to one-dimensional systems with broken time reversal symmetry. Finally, the electronic and structural properties of ultrathin metallic layers and nanoparticles will be studied by combining ab-initio and semi-empirical methods.
Significance for science
The accomplished research activity encompasses five research fields, covering a number of topics in the theory of statistical physics and condensed matter physics, which are at the forefront of research activities worldwide and have great application potential for new technologies. The research milestones set by our group have a firm basis in the achievements accomplished so far and internationally recognized for its quality. In the past five-year period we have published more than 100 papers in peer-reviewed journals, out of those one in Nature and 16 in Physical Review Letters. Furthermore, we have presented our achievements in over 70 invited talks on international conferences and have organized 8 international conferences. One of our basic concerns has always been and still is in keeping up-to-date with the development of high-performance-computation infrastructure, however scaled financially to budget limitations. Nevertheless, we have been able to keep pace with the development of new theoretical approaches and numerical methods and have contributed our own numerical method for studying quantum systems at finite temperature, e.g., the finite temperature Lanczos method. For the same reason we have been successful in keeping up-to-date with most recent challenges, brought about, e.g., by the discovery of new materials such as the REFeAs oxide (RE=rare earth), a compound exhibiting high transition temperature to the superconducting phase, or in the fast growing field of quantum computation and nano-devices. Below we briefly summarize and highlight the main topics of research. In the theory of strongly correlated electrons we mainly addressed issues related to models related to the phenomenon of high-Tc superconductivity, to frustrated spin systems and to their anomalous thermal and transport properties. The ever growing list of new materials, while tantalizing for materials' physical properties, offers unforeseen opportunities for technological applications in many areas of human activity (e.g., high transition temperature to superconducting state, anomalously large thermal conduction of certain low-dimensional insulating spin systems etc.). 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 subject of our third research topic, 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. This subject is of great importance for the field of cryptography. The fourth 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 potentially large impact in a vast area of socio-economic infrastructure, and to relaxor ferroelectrics, materials exhibiting properties of great interest for applications. Last, but not least, efforts were devoted to the development and application of novel numerical methods for quantum systems. As already noted, we have been able to develop such a method and aim to upgrade the method and invent new ones.
Significance for the country
We are confident that our community as a whole benefits from our research efforts – which we strive to keep on an as high level as possible – for several reasons. While keeping pace with research at the forefront of the many topics in statistical physics and physics of the solid state, we were able to competitively interact with research groups worldwide, thus providing direct means for the enrichment of national scientific and cultural heritage. Organization of 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 contribute also to our self awareness and confidence as a small nation amid the global community. We would like to underscore two more spin-off segments of our research activity for the nationwide benefit: the education of students and young researchers through the constant involvement in teaching processes at the Universities of Ljubljana and Maribor and at the J. Stefan International Postgraduate School. Another segment is maintenance of high-level research conditions, being a sine-qua-non for achieving a high added value to our domestic “products”, either intellectual or material, in the world of global economy.
Most important scientific results Final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Final report, complete report on dLib.si
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