Topological Multipartite Entanglement in a Fermi Liquid

We show that the topology of the Fermi sea of a D-dimensional Fermi gas is reflected in the multipartite entanglement characterizing D+1 regions that meet at a point. For odd D we introduce the multipartite mutual information and show that it exhibits a log^{D}L divergence as a function of system si...

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Main Authors: Pok Man Tam, Martin Claassen, Charles L. Kane
Format: Article
Language:English
Published: American Physical Society 2022-08-01
Series:Physical Review X
Online Access:http://doi.org/10.1103/PhysRevX.12.031022
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author Pok Man Tam
Martin Claassen
Charles L. Kane
author_facet Pok Man Tam
Martin Claassen
Charles L. Kane
author_sort Pok Man Tam
collection DOAJ
description We show that the topology of the Fermi sea of a D-dimensional Fermi gas is reflected in the multipartite entanglement characterizing D+1 regions that meet at a point. For odd D we introduce the multipartite mutual information and show that it exhibits a log^{D}L divergence as a function of system size L with a universal coefficient that is proportional to the Euler characteristic χ_{F} of the Fermi sea. This provides a generalization, for a Fermi gas, of the well-known result for D=1 that expresses the logL divergence of the bipartite entanglement entropy in terms of the central charge c characterizing a conformal field theory. For even D we introduce a charge-weighted entanglement entropy that is manifestly odd under a particle-hole transformation. We show that the corresponding charge-weighted mutual information exhibits a similar log^{D}L divergence proportional to χ_{F}. Our analysis relates the universal behavior of the multipartite mutual information in the absence of interactions to the D+1 order equal-time density correlation function, which we show exhibits a universal behavior in the long wavelength limit proportional to χ_{F}. Our analytic results are based on the replica method. In addition, we perform a numerical study of the charge-weighted mutual information for D=2 that confirms several aspects of the analytic theory. Finally, we consider the effect of interactions perturbatively within the replica theory. We show that for D=3 the log^{3}L divergence of the topological mutual information is not perturbed by weak short-ranged interactions, though for D=2 the charge-weighted mutual information is perturbed. Thus, for D=3 the multipartite mutual information provides a robust classification that distinguishes distinct topological Fermi liquid phases.
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spelling doaj.art-162d73def2b84a2c8d710f50637266902022-12-22T00:52:36ZengAmerican Physical SocietyPhysical Review X2160-33082022-08-0112303102210.1103/PhysRevX.12.031022Topological Multipartite Entanglement in a Fermi LiquidPok Man TamMartin ClaassenCharles L. KaneWe show that the topology of the Fermi sea of a D-dimensional Fermi gas is reflected in the multipartite entanglement characterizing D+1 regions that meet at a point. For odd D we introduce the multipartite mutual information and show that it exhibits a log^{D}L divergence as a function of system size L with a universal coefficient that is proportional to the Euler characteristic χ_{F} of the Fermi sea. This provides a generalization, for a Fermi gas, of the well-known result for D=1 that expresses the logL divergence of the bipartite entanglement entropy in terms of the central charge c characterizing a conformal field theory. For even D we introduce a charge-weighted entanglement entropy that is manifestly odd under a particle-hole transformation. We show that the corresponding charge-weighted mutual information exhibits a similar log^{D}L divergence proportional to χ_{F}. Our analysis relates the universal behavior of the multipartite mutual information in the absence of interactions to the D+1 order equal-time density correlation function, which we show exhibits a universal behavior in the long wavelength limit proportional to χ_{F}. Our analytic results are based on the replica method. In addition, we perform a numerical study of the charge-weighted mutual information for D=2 that confirms several aspects of the analytic theory. Finally, we consider the effect of interactions perturbatively within the replica theory. We show that for D=3 the log^{3}L divergence of the topological mutual information is not perturbed by weak short-ranged interactions, though for D=2 the charge-weighted mutual information is perturbed. Thus, for D=3 the multipartite mutual information provides a robust classification that distinguishes distinct topological Fermi liquid phases.http://doi.org/10.1103/PhysRevX.12.031022
spellingShingle Pok Man Tam
Martin Claassen
Charles L. Kane
Topological Multipartite Entanglement in a Fermi Liquid
Physical Review X
title Topological Multipartite Entanglement in a Fermi Liquid
title_full Topological Multipartite Entanglement in a Fermi Liquid
title_fullStr Topological Multipartite Entanglement in a Fermi Liquid
title_full_unstemmed Topological Multipartite Entanglement in a Fermi Liquid
title_short Topological Multipartite Entanglement in a Fermi Liquid
title_sort topological multipartite entanglement in a fermi liquid
url http://doi.org/10.1103/PhysRevX.12.031022
work_keys_str_mv AT pokmantam topologicalmultipartiteentanglementinafermiliquid
AT martinclaassen topologicalmultipartiteentanglementinafermiliquid
AT charleslkane topologicalmultipartiteentanglementinafermiliquid