Functional Integration and Dynamics of a Heisenberg Ferromagnet at high temperatures
Journal of Experimental and Theoretical Physics. 1986. Vol. 64. No. 6. P. 1373-1375.
, , Journal of Experimental and Theoretical Physics 1989 Vol. 68 No. 1 P. 119-125
Added: March 30, 2017
, International Journal of Modern Physics B 1996 Vol. 10 No. 18-19 P. 2189-2215
A number of problems in statistical physics can be reformulated in terms of a two-state system evolving in a random field. The corresponding evolution operator can be written in the form of time-ordered operator exponential. Functional formalism allows us to rewrite the latter as a product of usual matrix exponentials using a nonlinear change of ...
Added: March 28, 2017
, , Physical Review B: Condensed Matter and Materials Physics 1994 Vol. 49 No. 5 P. 3592-3595
Infinite-temperature long-time dynamics of Heisenberg model H^=-1/2tsumi,jJijS^i⋅S^j is investigated. It is shown that the quantum-spin pair correlator is equal to the correlator of a classically evaluated vector field averaged over the initial conditions with respect to the Gaussian measure. In the continuous-limit case, the scaling estimations allow one to find the one-point correlator that turns out to ...
Added: March 28, 2017
, , Journal of Experimental and Theoretical Physics 1994 Vol. 79 No. 5 P. 824-832
Using the functional integration method we compute exactly the time-dependent correlation functions of local spins in a finite quantum Heisenberg magnet with a position-independent exchange between spins. Explicit expressions for such correlation functions for an arbitrary number (N) of spins in the cluster and for all temperatures are presented. The spin correlation function for a cluster placed in an ...
Added: March 28, 2017
, , Physical Review B: Condensed Matter and Materials Physics 1995 Vol. 51 No. 6 P. 3974-3977
The transverse autocorrelation function at an arbitrary temperature is calculated rigorously for a system with an arbitrary number of quantum spins, each of which is coupled to all the other spins with equal exchange. It is shown that the cluster approximation, formed by a model for a real magnet, explains short- and intermediate-time (up to ...
Added: March 28, 2017
, Annals of Physics 1990 Vol. 202 No. 1 P. 165-185
The representation of the generating functional for quantum Heisenberg ferromagnets as an integral over two uncostrained c-number valued fields, charged and neutral, obeying the initial conditions (instead of commonly used periodic boundary conditions) is obtained. With the help of this representation the long-time dynamics of the longitudinal spin component at low temperatures is studied. The infrared-singular ...
Added: March 29, 2017
, Oxford : Oxford University Press, 2018
In recent years, the physics community has experienced a revival of interest in spin effects in solid state systems. On one hand, the solid state systems, particularly, semiconductors and semiconductor nanosystems, allow us to perform benchtop studies of quantum and relativistic phenomena. On the other hand, this interest is supported by the prospects of realizing ...
Added: January 13, 2021
, Physics Letters A 1986 Vol. 114 No. 2 P. 99-104
The partition function of the quantum Heisenberg ferromagnet is represented in a closed functional form. The resulting expression is a path integral for two interacting scalar Bose fields with non-polynomial action. ...
Added: March 31, 2017
Account of occasional wave breaking in numerical simulations of irregular water waves in the focus of the rogue wave problem
, , Water Waves, Springer 2019 P. 1-20
The issue of accounting of the wave breaking phenomenon in direct numerical simulations of oceanic waves is discussed. It is emphasized that this problem is crucial for the deterministic description of waves, and also for the dynamical calculation of extreme wave statistical characteristics, such as rogue wave height probability, asymmetry, etc. The conditions for accurate ...
Added: October 13, 2019
Control of the exciton valley dynamics in atomically thin semiconductors by tailoring the environment
, , et al., Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 103 No. 8 P. 085302-1-085302-12
The exciton valley dynamics in van der Waals heterostructures with transition metal dichalcogenide monolayers is driven by the long-range exchange interaction between the electron and the hole in the exciton. It couples the states active in the opposite circular polarizations resulting in the longitudinal-transverse splitting of excitons propagating in the monolayer plane. Here we study ...
Added: March 5, 2021
Nonlinear wave run-up in bays of arbitrary cross-section: generalization of the Carrier-Greenspan approach
, , , Journal of Fluid Mechanics 2014 Vol. 748 P. 416-432
We present an exact analytical solution of the nonlinear shallow water theory for wave run-up in inclined channels of arbitrary cross-section, which generalizes previous studies on wave run-up for a plane beach and channels of parabolic cross-section. The solution is found using a hodograph-type transform, which extends the well-known Carrier–Greenspan transform for wave run-up on ...
Added: November 19, 2014
, , , Journal of Geometry and Physics 2011 Vol. 61 P. 1203-1222
We present a summary of current knowledge about the AGT relations for conformal blocks with additional insertion of the simplest degenerate operator, and a special choice of the corresponding intermediate dimension, when the conformal blocks satisfy hypergeometric-type differential equations in position of the degenerate operator. A special attention is devoted to representation of conformal block ...
Added: February 28, 2013
, , Physical Review B: Condensed Matter and Materials Physics 2013 Vol. 88 No. 5 P. 054505-1-054505-10
We investigate the effect of interacting quantum phase slips on persistent current and its fluctuations in ultrathin superconducting nanowires and nanorings pierced by the external magnetic flux. We derive the effective action for these systems and map the original problem onto an effective sine-Gordon theory on torus. We evaluate both the flux dependent persistent current ...
Added: February 9, 2015
, Journal of Physics: Conference Series 2017 Vol. 804 No. 012036 P. 1-8
We investigate the existence and the orthogonality of the generalized Jack symmetric functions which play an important role in the AGT relations. We show their orthogonality by deforming them to the generalized Macdonald symmetric functions. ...
Added: October 26, 2017
Studying the specific features of free rise of solid spheres in a viscous fluids at moderate Reynolds numbers
, , et al., European Journal of Mechanics - B/Fluids 2018 Vol. 72 P. 616-623
The paper presents results of numerical simulations of freely rising solid spheres in a viscous fluid. The diameter of spheres was 5 mm, 7 mm, 10 mm, and 20 mm, and the corresponding Reynolds numbers varies in the interval 1400 < Re < 10100. It has been found that the free rise path varies, as the Galileo number ...
Added: October 21, 2018
М. : ИКИ РАН, 2011
Added: March 26, 2013
, , , Journal of High Energy Physics 2012 Vol. 1210
The reduction of the duality invariant approach to M-theory by a U-duality group valued Scherk-Schwarz twist is considered. We show that all gaugings of SUGRA can be obtained by dimensional reduction of the extended space. ...
Added: October 20, 2014
, , et al., Теоретическая и математическая физика 2019 Т. 200 № 2 С. 290-309
Leading logarithms in massless nonrenormalizable effective field theories can be computed using nonlinear recurrence relations. These recurrence relations follow from the fundamental requirements of unitarity, analyticity, and crossing symmetry of scattering amplitudes and generalize the renormalization group technique to the case of nonrenormalizable effective field theories. We review the existing exact solutions of nonlinear recurrence relations relevant for field ...
Added: September 29, 2020
, , , Нелинейная динамика 2017 Т. 13 № 3 С. 399-412
В статье, используя методы теории динамических систем Морса–Смейла, авторы рассматривают топологическую структуру для точечно-зарядной модели магнитного поля областей фотосферы. Для произвольного количества зарядов (безотносительно к их местоположению) и не предполагая потенциальности поля <span data-mathml="B⃗ (следовательно, не используя конкретных формул), авторы приводят оценки, связывающие количества зарядов определенного типа с количеством нуль-точек. Для граничных оценок описывается топологическая структура магнитного ...
Added: October 12, 2017
, , Physical Review D - Particles, Fields, Gravitation and Cosmology 2010 Vol. 81 P. 085010
We show that Polchinski equations in the D-dimensional matrix scalar field theory can be reduced at large N to the Hamiltonian equations in a (D+1)-dimensional theory. In the subsector of the Trϕl (for all l) operators we find the exact form of the corresponding Hamiltonian. The relation to the holographic renormalization group is discussed. ...
Added: February 27, 2013
, , Polymer Science - Series C 2018 Vol. 60 No. Supplement 1 P. 148-159
Theoretical models of the conformational behavior of flexible polymer chains in mixed solvents enunciated in the world literature during the last decade are critically reviewed. Models describing different mechanisms of coil-to-globule transitions in a good solvent induced by cosolvent addition are highlighted. Special attention is given to the analysis of theoretical approaches to describing the ...
Added: November 30, 2018
Temperature distribution in driven granular mixtures does not depend on mechanism of energy dissipation
, , , Scientific Reports 2020 Vol. 10 Article 693
We study analytically and numerically the distribution of granular temperatures in granular mixtures for different dissipation mechanisms of inelastic inter-particle collisions. Both driven and force-free systems are analyzed. We demonstrate that the simplified model of a constant restitution coefficient fails to predict even qualitatively a granular temperature distribution in a homogeneous cooling state. At the same time we reveal ...
Added: February 25, 2020
, , Scientific Reports 2018 Vol. 8 No. 1 P. 16915-1-16915-18
Sequential state discrimination is a strategy for quantum state discrimination of a sender’s quantum states when N receivers are separately located. In this report, we propose optical designs that can perform sequential state discrimination of two coherent states. For this purpose, we consider not only binary phase-shifting-key (BPSK) signals but also general coherent states, with arbitrary prior probabilities. Since ...
Added: November 16, 2020
, , et al., Труды НГТУ им. Р.Е. Алексеева 2012 № 2(95) С. 48-65
Purpose: Numerical modeling of internal baroclinic disturbances of different shapes in a model lake with variable depth, analysis of velocity field of wave-induced current, especially in the near-bed layer. Approach: The study is carried out with the use of numerical full nonlinear nonhydrostatic model for stratified fluid. Findings: The full nonlinear numerical modeling of internal wave dynamics ...
Added: October 6, 2012