Learning the non-Markovian features of subsystem dynamics

Fuente: arXiv
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Main Authors: Coppola, Michele, Bañuls, Mari Carmen, Lenarčič, Zala
Format: Preprint
Published: 2025
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author Coppola, Michele
Bañuls, Mari Carmen
Lenarčič, Zala
author_facet Coppola, Michele
Bañuls, Mari Carmen
Lenarčič, Zala
contents The dynamics of local observables in a quantum many-body system can be formally described in the language of open systems. The problem is that the bath representing the complement of the local subsystem generally does not allow the common simplifications often crucial for such a framework. Leveraging tensor network calculations and optimization tools from machine learning, we extract and characterize the dynamical maps for single- and two-site subsystems embedded in an infinite quantum Ising chain after a global quench. We consider three paradigmatic regimes: integrable critical, integrable non-critical, and chaotic. For each we find the optimal time-local representation of the subsystem dynamics at different times. We explore the properties of the learned time-dependent Liouvillians and whether they can be used to forecast the long-time dynamics of local observables beyond the times accessible through direct quantum many-body numerical simulation. Our procedure naturally suggests a novel measure of non-Markovianity based on the distance between the quasi-exact dynamical map and the closest CP-divisible form and reveals that criticality leads to the closest Markovian representation at large times.
format Preprint
id arxiv_https___arxiv_org_abs_2507_14133
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Learning the non-Markovian features of subsystem dynamics
Coppola, Michele
Bañuls, Mari Carmen
Lenarčič, Zala
Statistical Mechanics
Quantum Physics
The dynamics of local observables in a quantum many-body system can be formally described in the language of open systems. The problem is that the bath representing the complement of the local subsystem generally does not allow the common simplifications often crucial for such a framework. Leveraging tensor network calculations and optimization tools from machine learning, we extract and characterize the dynamical maps for single- and two-site subsystems embedded in an infinite quantum Ising chain after a global quench. We consider three paradigmatic regimes: integrable critical, integrable non-critical, and chaotic. For each we find the optimal time-local representation of the subsystem dynamics at different times. We explore the properties of the learned time-dependent Liouvillians and whether they can be used to forecast the long-time dynamics of local observables beyond the times accessible through direct quantum many-body numerical simulation. Our procedure naturally suggests a novel measure of non-Markovianity based on the distance between the quasi-exact dynamical map and the closest CP-divisible form and reveals that criticality leads to the closest Markovian representation at large times.
title Learning the non-Markovian features of subsystem dynamics
topic Statistical Mechanics
Quantum Physics
url https://arxiv.org/abs/2507.14133