Exact mean-field solution of a spin chain with short-range and long-range interactions

We consider the transverse field Ising model with additional all-to-all interactions between the spins. We show that a mean-field treatment of this model becomes exact in the thermodynamic limit, despite the presence of 1D short-range interactions. Namely, we show that the eigenstates of the model a...

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Main Author: Etienne Granet
Format: Article
Language:English
Published: SciPost 2023-05-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.14.5.133
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author Etienne Granet
author_facet Etienne Granet
author_sort Etienne Granet
collection DOAJ
description We consider the transverse field Ising model with additional all-to-all interactions between the spins. We show that a mean-field treatment of this model becomes exact in the thermodynamic limit, despite the presence of 1D short-range interactions. Namely, we show that the eigenstates of the model are coherent states with an amplitude that varies through the Hilbert space, within which expectation values of local observables can be computed with mean-field theory. We study then the thermodynamics of the model and identify the different phases. Among its peculiar features, this 1D model possesses a second-order phase transition at finite temperature and exhibits inverse melting.
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spelling doaj.art-f51e8654b4ec46c3a99cbd3255b8f4032023-05-26T11:32:03ZengSciPostSciPost Physics2542-46532023-05-0114513310.21468/SciPostPhys.14.5.133Exact mean-field solution of a spin chain with short-range and long-range interactionsEtienne GranetWe consider the transverse field Ising model with additional all-to-all interactions between the spins. We show that a mean-field treatment of this model becomes exact in the thermodynamic limit, despite the presence of 1D short-range interactions. Namely, we show that the eigenstates of the model are coherent states with an amplitude that varies through the Hilbert space, within which expectation values of local observables can be computed with mean-field theory. We study then the thermodynamics of the model and identify the different phases. Among its peculiar features, this 1D model possesses a second-order phase transition at finite temperature and exhibits inverse melting.https://scipost.org/SciPostPhys.14.5.133
spellingShingle Etienne Granet
Exact mean-field solution of a spin chain with short-range and long-range interactions
SciPost Physics
title Exact mean-field solution of a spin chain with short-range and long-range interactions
title_full Exact mean-field solution of a spin chain with short-range and long-range interactions
title_fullStr Exact mean-field solution of a spin chain with short-range and long-range interactions
title_full_unstemmed Exact mean-field solution of a spin chain with short-range and long-range interactions
title_short Exact mean-field solution of a spin chain with short-range and long-range interactions
title_sort exact mean field solution of a spin chain with short range and long range interactions
url https://scipost.org/SciPostPhys.14.5.133
work_keys_str_mv AT etiennegranet exactmeanfieldsolutionofaspinchainwithshortrangeandlongrangeinteractions