Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains

Recently, the steady states of non-unitary free fermion dynamics are found to exhibit novel critical phases with power-law squared correlations and a logarithmic subsystem entanglement. In this work, we theoretically understand the underlying physics by constructing solvable static/Brownian quadrati...

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Autores principales: Pengfei Zhang, Shao-Kai Jian, Chunxiao Liu, Xiao Chen
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Publicado: Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften 2021
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Acceso en línea:https://doaj.org/article/fe00f8683fad4b4fb9cfb6bb7b28207f
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spelling oai:doaj.org-article:fe00f8683fad4b4fb9cfb6bb7b28207f2021-11-16T12:16:53ZEmergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains2521-327X10.22331/q-2021-11-16-579https://doaj.org/article/fe00f8683fad4b4fb9cfb6bb7b28207f2021-11-01T00:00:00Zhttps://quantum-journal.org/papers/q-2021-11-16-579/pdf/https://doaj.org/toc/2521-327XRecently, the steady states of non-unitary free fermion dynamics are found to exhibit novel critical phases with power-law squared correlations and a logarithmic subsystem entanglement. In this work, we theoretically understand the underlying physics by constructing solvable static/Brownian quadratic Sachdev-Ye-Kitaev chains with non-Hermitian dynamics. We find the action of the replicated system generally shows (one or infinite copies of) ${O(2)\times O(2)}$ symmetries, which is broken to ${O(2)}$ by the saddle-point solution. This leads to an emergent conformal field theory of the Goldstone modes. We derive the effective action and obtain the universal critical behaviors of squared correlators. Furthermore, the entanglement entropy of a subsystem ${A}$ with length ${L_A}$ corresponds to the energy of the half-vortex pair ${S\sim \rho_s \log L_A}$, where ${\rho_s}$ is the total stiffness of the Goldstone modes. We also discuss special limits with more than one branch of Goldstone modes and comment on interaction effects.Pengfei ZhangShao-Kai JianChunxiao LiuXiao ChenVerein zur Förderung des Open Access Publizierens in den QuantenwissenschaftenarticlePhysicsQC1-999ENQuantum, Vol 5, p 579 (2021)
institution DOAJ
collection DOAJ
language EN
topic Physics
QC1-999
spellingShingle Physics
QC1-999
Pengfei Zhang
Shao-Kai Jian
Chunxiao Liu
Xiao Chen
Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains
description Recently, the steady states of non-unitary free fermion dynamics are found to exhibit novel critical phases with power-law squared correlations and a logarithmic subsystem entanglement. In this work, we theoretically understand the underlying physics by constructing solvable static/Brownian quadratic Sachdev-Ye-Kitaev chains with non-Hermitian dynamics. We find the action of the replicated system generally shows (one or infinite copies of) ${O(2)\times O(2)}$ symmetries, which is broken to ${O(2)}$ by the saddle-point solution. This leads to an emergent conformal field theory of the Goldstone modes. We derive the effective action and obtain the universal critical behaviors of squared correlators. Furthermore, the entanglement entropy of a subsystem ${A}$ with length ${L_A}$ corresponds to the energy of the half-vortex pair ${S\sim \rho_s \log L_A}$, where ${\rho_s}$ is the total stiffness of the Goldstone modes. We also discuss special limits with more than one branch of Goldstone modes and comment on interaction effects.
format article
author Pengfei Zhang
Shao-Kai Jian
Chunxiao Liu
Xiao Chen
author_facet Pengfei Zhang
Shao-Kai Jian
Chunxiao Liu
Xiao Chen
author_sort Pengfei Zhang
title Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains
title_short Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains
title_full Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains
title_fullStr Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains
title_full_unstemmed Emergent Replica Conformal Symmetry in Non-Hermitian SYK$_2$ Chains
title_sort emergent replica conformal symmetry in non-hermitian syk$_2$ chains
publisher Verein zur Förderung des Open Access Publizierens in den Quantenwissenschaften
publishDate 2021
url https://doaj.org/article/fe00f8683fad4b4fb9cfb6bb7b28207f
work_keys_str_mv AT pengfeizhang emergentreplicaconformalsymmetryinnonhermitiansyk2chains
AT shaokaijian emergentreplicaconformalsymmetryinnonhermitiansyk2chains
AT chunxiaoliu emergentreplicaconformalsymmetryinnonhermitiansyk2chains
AT xiaochen emergentreplicaconformalsymmetryinnonhermitiansyk2chains
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