Computable measures of non-Markovianity for Gaussian free fermion systems

Fuente: arXiv
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Main Author: Chiriacò, Giuliano
Format: Preprint
Published: 2025
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author Chiriacò, Giuliano
author_facet Chiriacò, Giuliano
contents We investigate measures of non-Markovianity in open quantum systems governed by Gaussian free fermionic dynamics. Standard indicators of non-Markovian behavior, such as the BLP and LFS measures, are revisited in this context. We show that for Gaussian states, trace-based distances -- specifically the Hilbert-Schmidt norm -- and second-order Rényi mutual information can be efficiently expressed in terms of two-point correlation functions, enabling practical computation even in systems where the full density matrix is intractable. Crucially, this framework remains valid even when the density matrix of the system is an average over stochastic Gaussian trajectories, yielding a non-Gaussian state. We present efficient numerical protocols based on this structure and demonstrate their feasibility through a small-scale simulation. Our approach opens a scalable path to quantifying non-Markovianity in interacting or measured fermionic systems, with applications in quantum information and non-equilibrium quantum dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25953
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Computable measures of non-Markovianity for Gaussian free fermion systems
Chiriacò, Giuliano
Quantum Physics
Other Condensed Matter
We investigate measures of non-Markovianity in open quantum systems governed by Gaussian free fermionic dynamics. Standard indicators of non-Markovian behavior, such as the BLP and LFS measures, are revisited in this context. We show that for Gaussian states, trace-based distances -- specifically the Hilbert-Schmidt norm -- and second-order Rényi mutual information can be efficiently expressed in terms of two-point correlation functions, enabling practical computation even in systems where the full density matrix is intractable. Crucially, this framework remains valid even when the density matrix of the system is an average over stochastic Gaussian trajectories, yielding a non-Gaussian state. We present efficient numerical protocols based on this structure and demonstrate their feasibility through a small-scale simulation. Our approach opens a scalable path to quantifying non-Markovianity in interacting or measured fermionic systems, with applications in quantum information and non-equilibrium quantum dynamics.
title Computable measures of non-Markovianity for Gaussian free fermion systems
topic Quantum Physics
Other Condensed Matter
url https://arxiv.org/abs/2509.25953