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Zheleznogorsk, Russia

Ovchinnikov S.G.,RAS Kirensky Institute of Physics
JETP Letters | Year: 2011

The pressure-temperature phase diagram of magnesiowüstite has been constructed using the many-electron LDA+GTB approach. The phase diagram includes a quantum critical point at P c = 55 GPa and has a symmetrical distribution of high-spin and low-spin states. The existence of a metallic state in a narrow temperature range above the critical point is predicted. © 2011 Pleiades Publishing, Ltd. Source


Kolovsky A.R.,RAS Kirensky Institute of Physics
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We discuss a method for creating bright matter solitons by loading a Bose-Einstein condensate of atoms in a driven tilted optical lattice. It is shown that one can realize the self-focusing regime for the wave-packet dynamics by properly adjusting the phase of the driving field with respect to the phase of Bloch oscillations. If atom-atom interactions are larger than some critical value gmin, this self-focusing regime is followed by the formation of bright solitons. Increasing the interactions above another critical value gmax makes this process unstable. Instead of soliton formation one now meets the phenomenon of incoherent self-trapping. In this regime a fraction of atoms is trapped in incoherent localized wave packets, while the remaining atoms spread ballistically. © 2010 The American Physical Society. Source


Tyurnev V.V.,RAS Kirensky Institute of Physics
Progress In Electromagnetics Research B | Year: 2010

This paper is an overview of important concepts and formulas involved in the application of coupling coefficients of microwave resonators for the design of bandpass filters with a particular emphasis on the frequency dispersion of coupling coefficients. The presumptions and formulas are classified into accurate, approximate, and erroneous ones. Source


Martynov S.N.,RAS Kirensky Institute of Physics
JETP Letters | Year: 2012

A new incommensurate magnetic structure with a locally triangular orientation of spins has been proposed for a two-subsystem magnet with frustrated intersystem exchange and competition between exchanges in one of the subsystems. When the temperature is lowered, this structure appears from the antiferromagnetic state after a first-order phase transition. It transfers to the Yafet-Kittel triangular structure when the threshold conditions for the exchange interactions are fulfilled. An increase in the length of the frustrated exchange bonds leads to the appearance of an incommensurate phase with the local antiferromagnetic orientation of the sublattices in each subsystem between the commensurate antiferromagnetic and Yafet-Kittel phases. © 2012 Pleiades Publishing, Ltd. Source


Quantum dynamics of a charged particle in a two-dimensional (2D) lattice subject to magnetic and electric fields is a rather complicated interplay between cyclotron oscillations (the case of vanishing electric field) and Bloch oscillations (zero magnetic field), details of which has not yet been completely understood. In the present work we suggest to study this problem by using cold atoms in optical lattices. We introduce a one-dimensional (1D) model which can be easily realized in laboratory experiments with quasi-1D optical lattices and show that this model captures many features of the cyclotron-Bloch dynamics of the quantum particle in 2D square lattices. © 2012 Higher Education Press and Springer-Verlag Berlin Heidelberg. Source

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