Strongly Coupled 𝒫𝒯-Symmetric Models in Holography

Non-Hermitian quantum field theories are a promising tool to study open quantum systems. These theories preserve unitarity if <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT...

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Main Authors: Daniel Areán, David Garcia-Fariña, Karl Landsteiner
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Entropy
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Online Access:https://www.mdpi.com/1099-4300/27/1/13
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author Daniel Areán
David Garcia-Fariña
Karl Landsteiner
author_facet Daniel Areán
David Garcia-Fariña
Karl Landsteiner
author_sort Daniel Areán
collection DOAJ
description Non-Hermitian quantum field theories are a promising tool to study open quantum systems. These theories preserve unitarity if <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula> symmetry is respected, and in that case, an equivalent Hermitian description exists via the so-called Dyson map. Generically, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula>-symmetric non-Hermitian theories can also feature phases where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula> symmetry is broken and unitarity is lost. We review the construction of holographic duals to strongly coupled <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula>-symmetric quantum field theories and the study of their phase diagram. We next focus on spacetime-dependent non-Hermitian couplings: non-Hermitian quenches and lattices. They violate the null energy condition in the gravity dual. The lattices realize phases supporting an imaginary current that breaks <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula> symmetry spontaneously. Remarkably, these non-Hermitian lattices flow to a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula>-symmetric fixed point in the IR.
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spelling doaj-art-e31983dff425499285bfe6b33567320f2025-01-24T13:31:39ZengMDPI AGEntropy1099-43002024-12-012711310.3390/e27010013Strongly Coupled 𝒫𝒯-Symmetric Models in HolographyDaniel Areán0David Garcia-Fariña1Karl Landsteiner2Instituto de Física Teórica UAM/CSIC, Campus de Cantoblanco, c/Nicolás Cabrera 13-15, 28049 Madrid, SpainInstituto de Física Teórica UAM/CSIC, Campus de Cantoblanco, c/Nicolás Cabrera 13-15, 28049 Madrid, SpainInstituto de Física Teórica UAM/CSIC, Campus de Cantoblanco, c/Nicolás Cabrera 13-15, 28049 Madrid, SpainNon-Hermitian quantum field theories are a promising tool to study open quantum systems. These theories preserve unitarity if <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula> symmetry is respected, and in that case, an equivalent Hermitian description exists via the so-called Dyson map. Generically, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula>-symmetric non-Hermitian theories can also feature phases where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula> symmetry is broken and unitarity is lost. We review the construction of holographic duals to strongly coupled <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula>-symmetric quantum field theories and the study of their phase diagram. We next focus on spacetime-dependent non-Hermitian couplings: non-Hermitian quenches and lattices. They violate the null energy condition in the gravity dual. The lattices realize phases supporting an imaginary current that breaks <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula> symmetry spontaneously. Remarkably, these non-Hermitian lattices flow to a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi mathvariant="script">PT</mi></semantics></math></inline-formula>-symmetric fixed point in the IR.https://www.mdpi.com/1099-4300/27/1/13non-Hermitian physicsPT symmetrygauge/gravity duality
spellingShingle Daniel Areán
David Garcia-Fariña
Karl Landsteiner
Strongly Coupled 𝒫𝒯-Symmetric Models in Holography
Entropy
non-Hermitian physics
PT symmetry
gauge/gravity duality
title Strongly Coupled 𝒫𝒯-Symmetric Models in Holography
title_full Strongly Coupled 𝒫𝒯-Symmetric Models in Holography
title_fullStr Strongly Coupled 𝒫𝒯-Symmetric Models in Holography
title_full_unstemmed Strongly Coupled 𝒫𝒯-Symmetric Models in Holography
title_short Strongly Coupled 𝒫𝒯-Symmetric Models in Holography
title_sort strongly coupled 𝒫𝒯 symmetric models in holography
topic non-Hermitian physics
PT symmetry
gauge/gravity duality
url https://www.mdpi.com/1099-4300/27/1/13
work_keys_str_mv AT danielarean stronglycoupledptsymmetricmodelsinholography
AT davidgarciafarina stronglycoupledptsymmetricmodelsinholography
AT karllandsteiner stronglycoupledptsymmetricmodelsinholography