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Main Authors: Vedula, Bharadwaj, Moore, M. A., Sharma, Auditya
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2402.03711
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author Vedula, Bharadwaj
Moore, M. A.
Sharma, Auditya
author_facet Vedula, Bharadwaj
Moore, M. A.
Sharma, Auditya
contents One of the key predictions of Parisi's broken replica symmetry theory of spin glasses is the existence of a phase transition in an applied field to a state with broken replica symmetry. This transition takes place at the de Almeida-Thouless (AT) line in the $h-T$ plane. We have studied this line in the power-law diluted Heisenberg spin glass in which the probability that two spins separated by a distance $r$ interact with each other falls as $1/r^{2σ}$. In the presence of a random vector-field of variance $h_r^2$ the phase transition is in the universality class of the Ising spin glass in a field. Tuning $σ$ is equivalent to changing the dimension $d$ of the short-range system, with the relation being $d =2/(2σ-1)$ for $σ< 2/3$. We have found by numerical simulations that $h_{\text{AT}}^2 \sim (2/3 -σ)$ implying that the AT line does not exist below $6$ dimensions and that the Parisi scheme is not appropriate for spin glasses in three dimensions.
format Preprint
id arxiv_https___arxiv_org_abs_2402_03711
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Evidence that the AT transition disappears below six dimensions
Vedula, Bharadwaj
Moore, M. A.
Sharma, Auditya
Disordered Systems and Neural Networks
Statistical Mechanics
One of the key predictions of Parisi's broken replica symmetry theory of spin glasses is the existence of a phase transition in an applied field to a state with broken replica symmetry. This transition takes place at the de Almeida-Thouless (AT) line in the $h-T$ plane. We have studied this line in the power-law diluted Heisenberg spin glass in which the probability that two spins separated by a distance $r$ interact with each other falls as $1/r^{2σ}$. In the presence of a random vector-field of variance $h_r^2$ the phase transition is in the universality class of the Ising spin glass in a field. Tuning $σ$ is equivalent to changing the dimension $d$ of the short-range system, with the relation being $d =2/(2σ-1)$ for $σ< 2/3$. We have found by numerical simulations that $h_{\text{AT}}^2 \sim (2/3 -σ)$ implying that the AT line does not exist below $6$ dimensions and that the Parisi scheme is not appropriate for spin glasses in three dimensions.
title Evidence that the AT transition disappears below six dimensions
topic Disordered Systems and Neural Networks
Statistical Mechanics
url https://arxiv.org/abs/2402.03711