Mixing times and cutoffs in open quadratic fermionic systems

In classical probability theory, the term "cutoff" describes the property of some Markov chains to jump from (close to) their initial configuration to (close to) completely mixed in a very narrow window of time. We investigate how coherent quantum evolution affects the mixing properties...

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Main Author: Eric Vernier
Format: Article
Language:English
Published: SciPost 2020-10-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.9.4.049
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author Eric Vernier
author_facet Eric Vernier
author_sort Eric Vernier
collection DOAJ
description In classical probability theory, the term "cutoff" describes the property of some Markov chains to jump from (close to) their initial configuration to (close to) completely mixed in a very narrow window of time. We investigate how coherent quantum evolution affects the mixing properties in two fermionic quantum models (the "gain/loss" and "topological" models), whose time evolution is governed by a Lindblad equation quadratic in fermionic operators, allowing for a straightforward exact solution. We check that the phenomenon of cutoff extends to the quantum case and examine with some care how the mixing properties depend on the initial state, drawing different regimes of our models with qualitatively different behaviour. In the topological case, we further show how the mixing properties are affected by the presence of a long-lived edge zero mode when taking open boundary conditions.
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spelling doaj.art-6a1fa93a2311465d8ee6c6b051d566ef2022-12-22T03:00:22ZengSciPostSciPost Physics2542-46532020-10-019404910.21468/SciPostPhys.9.4.049Mixing times and cutoffs in open quadratic fermionic systemsEric VernierIn classical probability theory, the term "cutoff" describes the property of some Markov chains to jump from (close to) their initial configuration to (close to) completely mixed in a very narrow window of time. We investigate how coherent quantum evolution affects the mixing properties in two fermionic quantum models (the "gain/loss" and "topological" models), whose time evolution is governed by a Lindblad equation quadratic in fermionic operators, allowing for a straightforward exact solution. We check that the phenomenon of cutoff extends to the quantum case and examine with some care how the mixing properties depend on the initial state, drawing different regimes of our models with qualitatively different behaviour. In the topological case, we further show how the mixing properties are affected by the presence of a long-lived edge zero mode when taking open boundary conditions.https://scipost.org/SciPostPhys.9.4.049
spellingShingle Eric Vernier
Mixing times and cutoffs in open quadratic fermionic systems
SciPost Physics
title Mixing times and cutoffs in open quadratic fermionic systems
title_full Mixing times and cutoffs in open quadratic fermionic systems
title_fullStr Mixing times and cutoffs in open quadratic fermionic systems
title_full_unstemmed Mixing times and cutoffs in open quadratic fermionic systems
title_short Mixing times and cutoffs in open quadratic fermionic systems
title_sort mixing times and cutoffs in open quadratic fermionic systems
url https://scipost.org/SciPostPhys.9.4.049
work_keys_str_mv AT ericvernier mixingtimesandcutoffsinopenquadraticfermionicsystems