Year: 2026
Type: article
Abstract: Isolated quantum systems follow a reversible unitary evolution, which seems inconsistent with the irreversibility of macroscopic thermodynamics. We notice that such a paradox can be reconciled when focusing on the local relaxation process. Here, we study the exact dynamics of an isolated system, which contains a finite number of three-level systems. When focusing on the dynamics of local states and local observables, irreversible behaviors naturally appear. Though the entropy of the full many-body state always remains unchanged, the total correlation entropy of this system exhibits an irreversibly increasing behavior. Moreover, our variation analysis shows that, the total correlation entropy would achieve its theoretical maximum if each site is in a generalized one-body Boltzmann state, which is not solely determined by the energy but also depends on the onsite pseudo-spins, and such a theoretical correlation maximum is highly coincidental with the exact time evolution. In this sense, the total correlation entropy serves well as a generalized indicator for the dynamical irreversibility of the nonequilibrium relaxation in this isolated system.
Authors: Sheng-Wen 李 Li 圣文, Ning 吴 Wu 宁
Institution: Beijing Institute of Technology
Language: English
Topic: Quantum many-body systems
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Awards: G2360958107, G7025462267, G8079532987
OpenAlex ID: W4402502561