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## U(1) and SU(2) quantum dissipative systems: The Caldeira-Leggett vs. the Amegaokar-Eckern-Schön approaches

Journal of Experimental and Theoretical Physics. 2016. Vol. 122. P. 576-586.

There are two paradigmatic frameworks for treating quantum systems coupled to a dissipative environment: the Caldeira–Leggett and Ambegaokar–Eckern–Schön approaches. Here, we recall the differences between them and explain the consequences of applying each to a zero-dimensional spin (having an SU(2) symmetry) in a dissipative environment (a dissipative quantum dot near or beyond the Stoner instability point).

Keywords: spin dynamics

Kolokolov I., Chertkov M., 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

Belykh V. V., Kuntsevich A., Glazov M. M. et al., Physical Review X 2018 Vol. 8 P. 031021-1-031021-8

Manifestations of quantum interference effects in macroscopic objects are rare. Weak localization is one
of the few examples of such effects showing up in the electron transport through solid state. Here, we show
that weak localization becomes prominent also in optical spectroscopy via detection of the electron spin
dynamics. In particular, we find that weak localization controls the ...

Added: September 10, 2018

Glazov M., 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

S. K. Gotovko, L. E. Svistov, Kuzmenko A. M. et al., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 100 No. 17 P. 174412-1-174412-12

We present a combined experimental and theoretical investigation of the low-frequency ESR dynamics in the ordered phases of magnetic mineral linarite. This material consists of weakly coupled spin-1/2 chains of copper ions with frustrated ferro- and antiferromagnetic interactions. In zero magnetic field, linarite orders into a spiral structure and exhibits a peculiar magnetic phase diagram ...

Added: November 19, 2019

Kolokolov I., Chertkov M., 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

Kolokolov I., Journal of Experimental and Theoretical Physics 1986 Vol. 64 No. 6 P. 1373-1375

Added: March 31, 2017

Schad P., Shnirman A., Makhlin Y., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 93 P. 174420

The Majorana representation for spin operators enables efficient application of field-theoretical methods for the analysis of spin dynamics. Moreover, a wide class of spin correlation functions can be reduced to Majorana correlations of the same order, simplifying their calculation. For the spin-boson model, direct application of this method in the lowest order allows for a ...

Added: October 13, 2016

Kolokolov I., 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

Kolokolov I., Podivilov E., Journal of Experimental and Theoretical Physics 1989 Vol. 68 No. 1 P. 119-125

Added: March 30, 2017

Shchepetilnikov A., Khisameeva A., Nefyodov Y. A. et al., Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 103 No. 19 Article 195313

The spin relaxation of a strongly correlated electron system hosted in a narrow AlAs quantum well is studied experimentally in the regime of the quantum Hall ferromagnet, i.e., near odd fillings of the integer quantum Hall effect. The relaxation rate is evaluated by analyzing the linewidth of the electrically detected electron-spin resonance. The measured spin ...

Added: January 9, 2022

Shnirman A., Saha A., Burmistrov I. et al., Physical Review Letters 2015 Vol. 114 P. 176806

The presence of geometric phases is known to affect the dynamics of the systems involved. Here, we consider a quantum degree of freedom, moving in a dissipative environment, whose dynamics is described by a Langevin equation with quantum noise. We show that geometric phases enter the stochastic noise terms. Specifically, we consider small ferromagnetic particles ...

Added: October 15, 2016

Kolokolov I., Chertkov M., 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

Kolokolov I., 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

Ружицкая Д. Д., САМОЙЛЕНКО А. А., Иванов А. Д. et al., Optoelectronics, Instrumentation and Data Processing 2017 Vol. 54 No. 1 P. 1-8

This paper presents an algorithm for processing the transmission spectra of whisperinggallery optical microcavities for use as a nanoparticle detector. The algorithm is based on the broadening of the microcavity resonance curve during precipitation of nanoparticles on the microcavity surface. Experimental results on the detection of particles are compared with Langmuir adsorption theory. The contribution ...

Added: May 25, 2018

Katushkina O. A., Quemerais E., Izmodenov V.V. et al., JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 2017 Vol. 122 No. 11 P. 10921-10937

In this work, we present for the first time the Lyman α intensities measured by Voyager 1/UVS in 2003–2014 (at 90–130 AU from the Sun). During this period Voyager 1 measured the Lyman α emission in the outer heliosphere at an almost fixed direction close to the upwind (i.e.“ toward the interstellar flow). The data show an unexpected behavior in 2003–2009: the ...

Added: January 26, 2018

Alfimov M., Litvinov A., Journal of High Energy Physics 2022 No. 01 Article 43

We study regularization scheme dependence of beta-function for sigma models with two-dimensional target space. Working within four-loop approximation, we conjecture the scheme in which the beta-function retains only two tensor structures up to certain terms containing zeta_3. Using this scheme, we provide explicit solutions to RG flow equation corresponding to Yang-Baxter- and lambda-deformed SU(2)/U(1) sigma ...

Added: February 1, 2022

Panina I., Balandin S., Tsarev A. et al., International Journal of Molecular Sciences 2023 Vol. 24 No. 2 P. 1

To date, a number of lantibiotics have been shown to use lipid II — a highly conserved peptidoglycan precursor in the cytoplasmic membrane of bacteria — as their molecular target. The α-component (Lchα) of the two-component lantibiotic lichenicidin (Lchα), previously isolated from the Bacillus licheniformis VK21 strain, seems to contain two putative lipid II binding ...

Added: February 21, 2023

М. : National Instruments Russia, 2017

Содержание сборника составляют доклады с результатами оригинальных исследований и технических решений, ранее не публиковавшиеся. Мы надеемся, что предлагаемый сборник окажется полезным для специалистов, работающих в различных областях науки и техники, для широкого круга преподавателей, аспирантов и студентов ВУЗов, а также для преподавателей средних школ и технических колледжей. ...

Added: May 10, 2017

Boldyrev A., Hushchyn M., Karpov M. et al., The European Physical Journal C - Particles and Fields 2023 No. 83 P. 543-562

https://link.springer.com/article/10.1140/epjc/s10052-023-11673-x#Abs1 ...

Added: December 4, 2023

Nagaev K., Маношин А. А., Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 102 Article 155411

We calculate the electrical and thermal conductivity of a two-dimensional electron gas with strong spin-orbit
coupling in which the scattering is dominated by electron-electron collisions. Despite the apparent absence of
Galilean invariance in the system, the two-particle scattering does not affect the electrical conductivity above
the band-crossing point where both helicity bands are filled. Below the band-crossing point ...

Added: October 14, 2021

M. : Faculty of Physics, MSU, 2017

The Low Temperature Physics Conference is an international event held every three years, under the auspices of the IUPAP through its Commission C5 on Low Temperature Physics. The aim of these conferences is to exchange information and views among the members of the international scientific community in the general field of Low Temperature Physics. It ...

Added: October 1, 2017

Kuzmichev S. A., Kuzmicheva T. E., Tchesnokov S. N. et al., Journal of Superconductivity and Novel Magnetism 2016 Vol. 29 No. 4 P. 1111-1116

We present temperature dependences of the large and the small superconducting gaps measured directly by SnS-Andreev spectroscopy in various Fe-based superconductors and MgB2. The experimental L,S(T ) are wellfitted with a two-gap model based on Moskalenko and Suhl system of equations (supplemented with a BCS integral renormalization). From the fitting procedure, we estimate the key ...

Added: March 19, 2016

Min Namkung, Younghun K., 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

I.A. Cohn, S.V. Zaitsev-Zotov, Physical Review B: Condensed Matter and Materials Physics 2023 Vol. 108 No. 11 P. 115124-115124

We demonstrate that magnetoresistance of creeping charge-density waves in the quasi-one-dimensional
conductor o-TaS 3 changes its character from a negative parabolic at T 10 K, where it obeys the 1/T 2 law
to a weakly temperature-dependent negative nearly linear one at lower temperatures. The dominant contribution into the negative parabolic magnetoresistance comes from magnetic field induced ...

Added: October 25, 2023