Gluing together modular flows with free fermions

Abstract We revisit the calculation of multi-interval modular Hamiltonians for free fermions using a Euclidean path integral approach. We show how the multi-interval modular flow is obtained by gluing together the single interval modular flows. Using this relation, we obtain an exact expression for...

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Main Author: Gabriel Wong
Format: Article
Language:English
Published: SpringerOpen 2019-04-01
Series:Journal of High Energy Physics
Subjects:
Online Access:http://link.springer.com/article/10.1007/JHEP04(2019)045
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author Gabriel Wong
author_facet Gabriel Wong
author_sort Gabriel Wong
collection DOAJ
description Abstract We revisit the calculation of multi-interval modular Hamiltonians for free fermions using a Euclidean path integral approach. We show how the multi-interval modular flow is obtained by gluing together the single interval modular flows. Using this relation, we obtain an exact expression for the multi-interval modular Hamiltonian and entanglement entropy in agreement with existing results. An essential ingredient in our derivation is the introduction of the modular action. This determines the non-local field theory describing the free fermion reduced density matrix, and makes manifest it’s non-local conformal symmetry and U(1) Kacs-Moody symmetry.
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spelling doaj.art-4b4596096d3b4d848034c1ae0c9fd6d22022-12-22T01:16:32ZengSpringerOpenJournal of High Energy Physics1029-84792019-04-012019412810.1007/JHEP04(2019)045Gluing together modular flows with free fermionsGabriel Wong0Department of Physics, Fudan UniversityAbstract We revisit the calculation of multi-interval modular Hamiltonians for free fermions using a Euclidean path integral approach. We show how the multi-interval modular flow is obtained by gluing together the single interval modular flows. Using this relation, we obtain an exact expression for the multi-interval modular Hamiltonian and entanglement entropy in agreement with existing results. An essential ingredient in our derivation is the introduction of the modular action. This determines the non-local field theory describing the free fermion reduced density matrix, and makes manifest it’s non-local conformal symmetry and U(1) Kacs-Moody symmetry.http://link.springer.com/article/10.1007/JHEP04(2019)045Boundary Quantum Field TheoryConformal and W SymmetryConformal Field Theory
spellingShingle Gabriel Wong
Gluing together modular flows with free fermions
Journal of High Energy Physics
Boundary Quantum Field Theory
Conformal and W Symmetry
Conformal Field Theory
title Gluing together modular flows with free fermions
title_full Gluing together modular flows with free fermions
title_fullStr Gluing together modular flows with free fermions
title_full_unstemmed Gluing together modular flows with free fermions
title_short Gluing together modular flows with free fermions
title_sort gluing together modular flows with free fermions
topic Boundary Quantum Field Theory
Conformal and W Symmetry
Conformal Field Theory
url http://link.springer.com/article/10.1007/JHEP04(2019)045
work_keys_str_mv AT gabrielwong gluingtogethermodularflowswithfreefermions