פרופ' ויקטור קגלובסקי

In my research I study various applications of the network models, starting with the original Chalker-Coddington (CC) network model, proposed to describe the inter-plateaux transition in the integer quantum Hall effect (QHE) and based on its semi-classical picture. Different symmetries of the transfer matrices corresponding to novel symmetry classes allow studying the spin QHE and thermal QHE, as well as quantum spin Hall effect with a very nontrivial phase diagram. Two recently introduced network models: a weakly chiral network model on the square lattices, and a triangular network model, describe levitation of extended states at low magnetic fields. To study the effect of magnetic impurities on QHE the exact analytical expression for spin-dependent transmission coefficients is found. A fictitious nonunitary scattering matrix S is introduced for electrons, reproducing the exactly calculated scattering probabilities, with decoherence identified by the deviation of S from unitarity. My research is also devoted to a phenomenological description of topological insulators, two of its main results are the explanation of the experiment with asymmetric current electrodes and prediction of new quantum Hall effects in systems with ferromagnetic electrodes. My most recent research studies a sliding Luttinger liquid to model metal-insulator transition and to check the stability of edge states in topological insulators

I organized conferences in Dresden, Trieste, Loughborough, UK, and Pohang, South Korea. Last year together with German and US collaborators we have organized the program “Recent progress and perspectives in topological insulators: quantum Hall effects, ballistic vs. diffusive regimes and Anderson transitions” at  Kavli Institute for Theoretical Physics, China in April 2016. I have also been a Convener of the Advanced Study Group (August 24 - September 21, 2016) and Coordinator of the Workshop “Anderson Localization in Topological Insulators” at the Center for Theoretical Physics of Complex Systems, Institute of Basic Research, Daejeon, South Korea (September 5 – 9. 2016)

In September 2017 I have participated in the Advanced Study Group on Topological Phases in Arrays of Luttinger Liquid Wires at the Center for Theoretical Physics of Complex Systems, Institute of Basic Research, Daejeon, South Korea

In June – July 2018 I have participated in the Advanced Study Group: Edge Reconstruction in Quantum Hall Systems and Topological Insulators, and have been a Coordinator of the International Workshop on Edge Reconstruction: Topology and Quantum Phase Transitions on the Edge

I take part in two proposals in the framework of HORIZON2020 which are now under review: H2020-FETOPEN Optoelectronics of topological materials and Marie Skłodowska-Curie Actions, Research and Innovation Staff Exchange (RISE) Opto-Electronic Properties of Topological Materials

The recent project participated in as a Visiting Professor is Superconducting edges of the topological insulator at the Center for Theoretical Physics of Complex Systems, Institute of Basic Research, Daejeon, South Korea in June 2019. The main goal of this project is to study the emergence of superconductivity at the edge of topological insulators. We predict its existence even for typical repulsive interactions

In September 2019 was visiting Sophia University, Tokyo, under the “Japan Society for the Promotion of Science Invitational Fellowships for Research in Japan”. The main subject of the research has been Machine Learning of metal-insulator transition

This year (2022) I have returned to the Max-Planck-Institut für Physik komplexer Systeme, Dresden, Germany as a Visiting Professor for my annual two-months research. This January we have atarted to work on the project studying the conductance of many-channel strongly interacting one-dimensional system

My proposal (as a convener) for Advanced Study Group 2020-2022 Deep Learning in Quantum Phase Transition at the Center for Theoretical Physics of Complex Systems, Institute of Basic Research, Daejeon, South Korea, has been approved. The Advanced Study Group (ASG) will be held at the PCS in the period from mid–June to mid–July 2022

http://www.mpipks-dresden.mpg.de/~cormag08/

http://indico.ictp.it/event/a09147/

http://www.mpipks-dresden.mpg.de/~rpsat14/

https://www.apctp.org/plan.php/Delocalisation2015

https://pcs.ibs.re.kr/PCS_Workshops/PCS_ASG_ALTI.html

http://pcs.ibs.re.kr/PCS_Workshops/PCS_Anderson_Localization_in_Topological_Insulators.html

https://pcs.ibs.re.kr/PCS_Workshops/PCS_EdgeRec.html