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## Magnetodipolar interaction and quasiparticles delocalization in disordered quantum magnets

Journal of Magnetism and Magnetic Materials. 2022. Vol. 560. Article 169640.

Oleg I. Utesov

It is well-known that disordered quantum magnets usually host localized elementary excitations in gapped

phases. Here we show that long-range magnetodipolar interaction can lead to quasiparticles delocalization in

the three-dimensional case, similarly to the phenomenon previously described for localized vibrational modes

in disordered solids. Employing renormalization group-like ideas, the average eigenmode occupation number

is found to scale with the system size, which also leads to sub-diffusive dynamical properties of the system.

O.I. Utesov, Journal of Magnetism and Magnetic Materials 2021 Vol. 524 P. 167616

The analytical theory of density of states (DOS) in three-dimensional quantum magnets with the bond disorder is proposed based on the self-consistent T-matrix
approximation (SCTMA). It successfully describes the DOS both for resonant and non-resonant scattering, whose emergence is governed by the ratio of scattering
length and the average distance between impurities, which concentration is denoted as ...

Added: January 14, 2021

Blinov V. N., Наноструктуры. Математическая физика и моделирование 2014 Т. 10 № 1 С. 5-28

Учёт дальнодействующих взаимодействий является непростой особенностью компьютерного моделирования систем физики конденсированных сред. В то время как в моделировании кристаллов метод суммирования Эвальда позволяет учесть их естественную трансляционную симметрию, в случае жидких систем подобные схемы носят, скорее, эмпирический характер, и основаны на определённых приближениях и результатах моделирования. В данном обзоре рассмотрены основные методы, применяемые при моделировании ...

Added: June 6, 2014

Murod S. Bahovadinov, Kurlov D., Altshuler B. et al., 2022 Vol. 76 No. 7 Article 116

We study effects of disorder on eigenstates of 1D two-component fermions with infinitely strong Hubbard repulsion. We demonstrate that the spin-independent (potential) disorder reduces the problem to the one-particle Anderson localization taking place at arbitrarily weak disorder. In contrast, a random magnetic field can cause reentrant many-body localization–delocalization transitions. Surprisingly weak magnetic field destroys one-particle ...

Added: December 13, 2022

Sherbakov A., Oleg I. Utesov, Journal of Magnetism and Magnetic Materials 2021 Vol. 518 P. 167390

Motivated by recent experiments on quantum magnet NiCl2-4SC(NH2)2 (DTN) and its Br-doped counterpart DTNX we propose a theoretical description of optical magnon branch in the antiferromagnet with large single-ion
anisotropy in the magnetically ordered phase. In the framework of the 1/S expansion we derive analytical
expressions for optical magnon with \bf{k} = 0 energy magnetic field dependence ...

Added: January 15, 2021

Tikhonov K., Ioselevich A., Feigelman M., Annals of Physics 2021 Vol. 435 Article 168524

We study deterministic power-law quantum hopping model with an amplitude J(r)~r^{-\beta} and local Gaussian disorder in low dimensions d=1 or 2 under the condition d<\beta<3/2\d. We demonstrate unusual combination of exponentially decreasing density of the ”tail states” and localization–delocalization transition (as function of disorder strength W) pertinent to a small (vanishing in thermodynamic limit) fraction ...

Added: October 17, 2021

Tikhonov K., Mirlin A. D., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 99 No. 2 P. 024202-1-024202-25

Dynamical and spatial correlations of eigenfunctions as well as energy level correlations in the Anderson model on random regular graphs (RRG) are studied. We consider the critical point of the Anderson transition and the delocalized phase. In the delocalized phase near the transition point, the observables show a broad critical regime for system sizes N ...

Added: January 7, 2019

O. Valba, Gorsky A., JETP Letters 2022 Vol. 116 No. 6 P. 398-404

We study numerically the Anderson model on partially disordered random regular graphs considered as the toy model for a Hilbert space of interacting disordered many-body system. The protected subsector of zero-energy states in a many-body system corresponds to clean nodes in random regular graphs ensemble. Using adjacent gap ratio statistics and inverse participation ratio we ...

Added: October 29, 2022

Kolokolov I., Journal of Experimental and Theoretical Physics 1993 Vol. 76 No. 6 P. 1099-1109

Starting from the Abrikosov-Ryzhkin formulation of the
1D random potential problem I find closed functional representations
for various physical quantities. These functional integrals are
calculated exactly without the use of any perturbative expansions.
The expressions for the multipoint densities correlators are
obtained. Then I evaluate the mean square dispersion of the size
of localized wave functions. As a physical application of ...

Added: March 29, 2017

Nosov P. A., Burmistrov I., Raghu S., Physical Review Letters 2020 Vol. 125 No. 25 P. 1-7

The interplay of interactions and disorder in two-dimensional (2D) electron systems has actively been studied for decades. The paradigmatic approach involves starting with a clean Fermi liquid and perturbing the system with both disorder and interactions. Instead, we start with a clean non-Fermi liquid near a 2D ferromagnetic quantum critical point and consider the effects ...

Added: January 28, 2021

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

Tikhonov K., Mirlin A. D., Skvortsov M. A., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 94 P. 220203-1-220203-6

A numerical study of Anderson transition on random regular graphs (RRGs) with diagonal disorder is performed.
The problem can be described as a tight-binding model on a lattice with N sites that is locally a tree with constant connectivity.
In a certain sense, the RRG ensemble can be seen as an infinite-dimensional (d→∞) cousin of the Anderson ...

Added: March 9, 2017

Tikhonov K., Mirlin A. D., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 94 P. 184203-1-184203-16

We investigate analytically and numerically eigenfunction statistics in a disordered system on a finite Bethe lattice (Cayley tree). We show that the wave-function amplitude at the root of a tree is distributed fractally in a large part of the delocalized phase. The fractal exponents are expressed in terms of the decay rate and the velocity ...

Added: March 9, 2017

Kolokolov I., EPL 1994 Vol. 28 No. 3 P. 193-196

For a given wave function one can define a quantity μE having the meaning of its inverse spatial size. The Laplace transform of the distribution function P(μE) is calculated analytically for a 1D disordered sample with a finite length L. ...

Added: March 28, 2017

Kolokolov I., Physica D: Nonlinear Phenomena 1995 Vol. 86 No. 1-2 P. 134-148

start from the derivation of the Abrikosov-Ryzhkin model for the 1D random potential problem. In its framework I find closed functional representations for various physical quantities. The representation uses number-valued fields only. These functional integrals are calculated exactly without the use of any perturbative expansions. Expressions for the multipoint densities correlators are obtained. These correlators ...

Added: March 28, 2017

Tikhonov K., Mirlin A. D., Physical Review B: Condensed Matter and Materials Physics 2021 Vol. 103 No. 6 Article 064204

We explore correlations of eigenstates around the many-body localization (MBL) transition in their dependence on the energy difference (frequency) ω and disorder W. In addition to the genuine many-body problem, XXZ spin chain in random field, we consider localization on random regular graphs that serves as a toy model of the MBL transition. Both models ...

Added: February 26, 2021

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

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

M.Yu. Kagan, JETP Letters 2016 Vol. 103 No. 11 P. 728-738

In this short review, we first discuss the results, which are mainly devoted to the generalizations of the famous Kohn–Luttinger mechanism of superconductivity in purely repulsive fermion systems at low electron densities. In the context of repulsive-U Hubbard model and Shubin–Vonsovsky model we consider briefly the superconducting phase diagrams and the symmetries of the order parameter ...

Added: November 18, 2016

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

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

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

Terekhovich V., Эпистемология и философия науки 2019 Т. 56 № 1 С. 169-184

The framework of simple opposition realism - anti-realism is not enough to analyze the views on the reality of unobservable objects of quantum theory. First, it is necessary to distinguish between realism in relation to the theory and realism in relation to the theory’s objects. Secondly, realism in relation to classical objects can be combined, ...

Added: February 12, 2020

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

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