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Collective Phenomena in Quantum Matter

Lehrstuhl Teoretische Physik III, Prof. Konstantin Efetov

Project target

1) To develop the theory of 2D quantum critical phenomena and on its basis to define basic phenomena in high temperature superconducting cuprates;

2) To develop software for numeral computation by quantum Monte Carlo method, escaping the well-known problem of fermion sign in strongly-coupled electronic systems and apply it for computing thermodynamic and kinetic properties in Hubbard 2D model;

 

3) To develop the theory of collective coherent quantum-mechanical phenomena in superconducting quantum metamaterials and hybrid hetero structures ferromagnetic/superconductor and apply it to experiments description.

The project offers a unique research direction Collective Phenomena in Quantum Matter. Its realization will provide for creation in NUST MISiS on the basis of Ustinov and Abrikosov laboratories of Quantum IT Centre which will become a part of fast growing international network.

Quantum criticality (critical behavior around quantum critical point) has become one of the most popular  research directions of the previous 20 years. At zero temperature when the system reaches certain threshold point, quantum fluctuations are so strong that metallic state is destroyed. Electrons no longer behave as stable quasi particles, but become heavy and short-lived, substantially changing thermos dynamic and transportation properties of such materials. Quantum Critical Points (QCP) belong to most violent disturbances applied to metallic states. Many publications consider quantum criticality as the reason for mysterious behavior of high temperature superconducting cuprates, heavy fermions and doped ferromagnetics. No doubt, it would be most interesting in quantum criticality theory to explain high temperature superconductivity in cuprates, discover more than 25 years ago by Bednorz and Müller.

Since then mare than 100 thousand articles have been published but, nevertheless, phenomena in cuprates still look mysterious. There is no general agreement on the mechanism of such high temperature superconducting  transition, which is the reason for pseudogap state of various structures, such as, for example, stripes, checkerboard order, etc.

 Professor Efetov started to explore this direction quite recently in 2012. The analyses of spin fermion (SF) model lead K.Efetov and his team to the conclusion that standard pattern of phase transformations with similarity principles and non-trivial degree values, cannot be applied to 2D SF model. Instead there is a psudogap state phase, characterized by a combination of superconducting and electron-hole states. Long-range order is destroyed by 2D fluctuations.

Superconductivity is stabilized at low temperatures but can be destroyed by weak magnetic field. In this case the system becomes an isolator with certain chessboard charge order instead of becoming a normal metal. This is an absolutely new forecast of processes in high temperature cuprates and the work was highly rated by scientific community and consequently the authors could publish an article in nature Physics.

Comparison of the theory and the experiment (after a few months after the publication) provokes discussion at various conferences and workshops. Research in this field (co-existence of stripe phase and superconductivity) has been carried for quite a long time at TFQT department by Mukhin team.  

This unexpected development of the field proves the project research is becoming more and more relative. The team is inspired to continue the research of quantum critical state .

1.     Polar Kerr effect from a time-reversal symmetry breaking unidirectional charge density wave      M. Gradhand, I. Eremin and J. Knolle          PHYSICAL REVIEW B; 91, 060512(R) (2015)

2.        Spin-charge ordering induced by magnetic field in superconducting state: Analytical self-consistent solution in the two-dimensional model. S. I. Matveenko and S. I. Mukhin; Europhysics Letters; 109, 57007 (2015)

3.        Spin current in junctions composed of multiband superconductors with a spin density wave. Andreas Moor, Anatoly F Volkov and Konstantin B Efetov; Superconductor Science and Technology; 28, 025011 (2015)

4.        Doping asymmetry of superconductivity coexisting with antiferromagnetism in spin fluctuation theory. W. Rowe, I. Eremin, A.T. Rømer, B.M. Andersen and P.J. Hirschfeld; New Journal of Physics; 17, 023022 (2015)

5.        Effects of lasing in a one-dimensional quantum metamaterial. Hidehiro Asai, Sergey Savel’ev, Shiro Kawabata, and Alexandre M. Zagoskin; PHYSICAL REVIEW B; 91, 134513 (2015)

6.        Quantum criticality in two dimensions and marginal Fermi liquid. K. B. Efetov; PHYSICAL REVIEW B; 91, 045110 (2015)

7.        Pairing gaps near ferromagnetic quantum critical points. M. Einenkel, H. Meier, C. P´epin, and K. B. Efetov; PHYSICAL REVIEW B; 91, 064507 (2015)

8.        Hidden order as a source of interface superconductivity. Andreas Moor, Anatoly F. Volkov, and Konstantin B. Efetov; PHYSICAL REVIEW B; 91, 064511 (2015)

9.        Euclidean action of fermi-system with ”hidden order”. S. I. Mukhin; PHYSICA B: PHYSICS OF CONDENSED MATTER; 460, 264 (2015)

10.     Higgs Mechanism and Anomalous Hall Effect in Three-Dimensional Topological Superconductors. Flavio S. Nogueira, Asle Sudbø, and Ilya Eremin; PHYSICAL REVIEW B; arXiv:1504.07993. 

11.     Pairing symmetry of the one-band Hubbard model in the paramagnetic weak-coupling limit: a numerical RPA study. A. T. Rømer, A. Kreisel ,I. Eremin, M. A. Malakhov, T. A. Maier, P. J. Hirschfeld, B. M. Andersen; PHYSICAL REVIEW B; arXiv:1506.03593. В процессе публикации.

12.     Superconducting phase diagram of itinerant antiferromagnets. A. T. Rømer, I. Eremin, P. J. Hirschfeld,B. M. Andersen; PHYSICAL REVIEW B; arXiv:1505.03003. В процессе публикации.

13.     Specular Interband Andreev Reflections in Graphene; D. K. Efetov, L. Wang, C. Handschin, K. B. Efetov, J. Shuang, R. Cava, T. Taniguchi, K. Watanabe, J. Hone, C. R. Dean, and P. Kim; Nature Physics; arXiv:1505.04812. 

14.     Josephson phase diffusion in small Josephson junctions: a strongly nonlinear regime. M. V. Fistul; No-nonsense Physicist. An Overview of Gabriele Giuliani's Work and Life (2015); arXiv:1405.1876.

15.     Electrodynamics of a planar Archimedean spiral resonator. N. Maleeva, N. N. Abramov, A. S. Averkin, M. V. Fistul, A. Karpov, A. P. Zhuravel, A. V. Ustinov; Journal of Applied Physics; arXiv:1411.5823.На рецензии

16.     Resonant enhancement of MQT in Josephson junctions: the influence of coherent two-level systems. M. V. Fistul; PHYSICAL REVIEW B; arXiv:1410.4388. 

17.     Enhanced polarization-sensitive broadband photoresponse from interface junction states in graphene. N. G. Kalugin, L.  Jing, E. S. Morell, M.C. Wanke, L. E. F. Foa Torres, M. V. Fistul and K.B. Efetov. 

18.     Classical and Quantum metastable states in SQUID based metamaterials in a strong coupling regime. K.V. Shulga, M. V. Fistul, A. V. Ustinov.

19.     Effect of Van Hove Singularities on d-form factor charge order in the cuprates. P. Volkov and K. B. Efetov. 

20. Surface states induced giant oscillations of the conductance in the quantum Hall regime. A. Kadigrobov and M. V. Fistul. 

Project objectives

The aim of the project is to develop the theory of collective phenomena in quantum matter for quantum computation.

Equipment

1.       Multifunctional color WiFi printer HP Color LaserJet Pro M476dw MFP

2.       WiFi router TP-LINK TL-WDR4300

3.       Digital projector Benq  MX806ST

4.       Lenovo IdeaCentre S20-00 (F0AY001RRK)

Events research team

International conference at NUST MISiS Superconductivity and Magnetism Interaction in Nano systems September 2-4, 2015

Partnership and cooperation

1.Ruhr-Universitat Bochum, Institut für Theoretische Physik III

2. Institute for Theoretical Physics, ETH Zurich,

3. Loughborough University, UK

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