Mutual information for fermionic systems

We study the behavior of the mutual information (MI) in various quadratic fermionic chains, with and without pairing terms and both with short- and long-range hoppings. The models considered include the short-range limit and long-range versions of the Kitaev model as well, and also cases in which th...

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Main Authors: Luca Lepori, Simone Paganelli, Fabio Franchini, Andrea Trombettoni
Format: Article
Language:English
Published: American Physical Society 2022-09-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.4.033212
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author Luca Lepori
Simone Paganelli
Fabio Franchini
Andrea Trombettoni
author_facet Luca Lepori
Simone Paganelli
Fabio Franchini
Andrea Trombettoni
author_sort Luca Lepori
collection DOAJ
description We study the behavior of the mutual information (MI) in various quadratic fermionic chains, with and without pairing terms and both with short- and long-range hoppings. The models considered include the short-range limit and long-range versions of the Kitaev model as well, and also cases in which the area law for the entanglement entropy is—logarithmically or nonlogarithmically—violated. In all cases surveyed, when the area law is violated at most logarithmically, the MI is a monotonically increasing function of the conformal four-point ratio x. Where nonlogarithmic violations of the area law are present, nonmonotonic features can be observed in the MI, and the four-point ratio, as well as other natural combinations of the parameters, is found not to be sufficient to capture the whole structure of the MI with a collapse onto a single curve. We interpret this behavior as a sign that the structure of peaks is related to a nonuniversal spatial configuration of Bell pairs. For the model exhibiting a perfect volume law, the MI vanishes identically. For the Kitaev model the MI is vanishing for x→0 and it remains zero up to a finite x in the gapped case. In general, a larger range of the pairing corresponds to a reduction of the MI at small x. A discussion of the comparison with the results obtained by the anti–de Sitter/conformal field theory correspondence in the strong-coupling limit is presented.
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spelling doaj.art-0ab8fadb00744638b62c812cde4eb4242024-04-12T17:24:32ZengAmerican Physical SocietyPhysical Review Research2643-15642022-09-014303321210.1103/PhysRevResearch.4.033212Mutual information for fermionic systemsLuca LeporiSimone PaganelliFabio FranchiniAndrea TrombettoniWe study the behavior of the mutual information (MI) in various quadratic fermionic chains, with and without pairing terms and both with short- and long-range hoppings. The models considered include the short-range limit and long-range versions of the Kitaev model as well, and also cases in which the area law for the entanglement entropy is—logarithmically or nonlogarithmically—violated. In all cases surveyed, when the area law is violated at most logarithmically, the MI is a monotonically increasing function of the conformal four-point ratio x. Where nonlogarithmic violations of the area law are present, nonmonotonic features can be observed in the MI, and the four-point ratio, as well as other natural combinations of the parameters, is found not to be sufficient to capture the whole structure of the MI with a collapse onto a single curve. We interpret this behavior as a sign that the structure of peaks is related to a nonuniversal spatial configuration of Bell pairs. For the model exhibiting a perfect volume law, the MI vanishes identically. For the Kitaev model the MI is vanishing for x→0 and it remains zero up to a finite x in the gapped case. In general, a larger range of the pairing corresponds to a reduction of the MI at small x. A discussion of the comparison with the results obtained by the anti–de Sitter/conformal field theory correspondence in the strong-coupling limit is presented.http://doi.org/10.1103/PhysRevResearch.4.033212
spellingShingle Luca Lepori
Simone Paganelli
Fabio Franchini
Andrea Trombettoni
Mutual information for fermionic systems
Physical Review Research
title Mutual information for fermionic systems
title_full Mutual information for fermionic systems
title_fullStr Mutual information for fermionic systems
title_full_unstemmed Mutual information for fermionic systems
title_short Mutual information for fermionic systems
title_sort mutual information for fermionic systems
url http://doi.org/10.1103/PhysRevResearch.4.033212
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AT simonepaganelli mutualinformationforfermionicsystems
AT fabiofranchini mutualinformationforfermionicsystems
AT andreatrombettoni mutualinformationforfermionicsystems