Restricted typicality in non-equilibrium quantum many-body systems
Abstract
Characterizing the time evolution of generic quantum many-body systems is a fundamental challenge, as representing the exact state requires exponentially scaling computational resources. While hydrodynamics and statistical mechanics successfully simplify this task by predicting the expectation values of local observables, these macroscopic frameworks provide no information about nonlinear characteristics of the quantum state. In this work, we demonstrate that for systems exhibiting a timescale separation, with dynamics governed by the transport of conserved charges, this lost information can be systematically recovered. By constraining the maximum-entropy Scrooge ensemble solely by the system's slow modes, we accurately reconstruct complex, nonlinear quantum properties of the global time-evolved state, including the half-chain entanglement entropy and the participation entropy in the computational basis. Our results generalize the paradigm of canonical typicality, revealing that a hydrodynamically bottlenecked system behaves as a typical pure state within a dynamically restricted submanifold of the Hilbert space - a phenomenon we term global restricted typicality.
Related
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- Mpemba effect in many-body systems near equilibrium
- Second Law of Thermodynamics in Closed Quantum Many-Body Systems
- Bootstrapping symmetries in quantum many-body systems from the cross spectral form factor
- A Few Constrain Many: Correlation-Enhanced Learning of Many-Body Quantum Systems
BibTeX
@misc{pawlik2026restricted,
title = {{Restricted typicality in non-equilibrium quantum many-body systems}},
author = {Konrad Pawlik and Piotr Sierant and Jakub Zakrzewski},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07832},
eprint = {2609.07832},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07832},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Restricted typicality in non-equilibrium quantum many-body systems
AU - Konrad Pawlik
AU - Piotr Sierant
AU - Jakub Zakrzewski
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07832
UR - https://arxiv.org/abs/2609.07832
AB - Characterizing the time evolution of generic quantum many-body systems is a fundamental challenge, as representing the exact state requires exponentially scaling computational resources. While hydrodynamics and statistical mechanics successfully simplify this task by predicting the expectation values of local observables, these macroscopic frameworks provide no information about nonlinear characteristics of the quantum state. In this work, we demonstrate that for systems exhibiting a timescale separation, with dynamics governed by the transport of conserved charges, this lost information can be systematically recovered. By constraining the maximum-entropy Scrooge ensemble solely by the system's slow modes, we accurately reconstruct complex, nonlinear quantum properties of the global time-evolved state, including the half-chain entanglement entropy and the participation entropy in the computational basis. Our results generalize the paradigm of canonical typicality, revealing that a hydrodynamically bottlenecked system behaves as a typical pure state within a dynamically restricted submanifold of the Hilbert space - a phenomenon we term global restricted typicality.
ER -