Work

Conditions for quantum violent relaxation

Year: 2025

Type: article

Abstract: While the dynamics of fully connected systems is dominated by mean-field effect, in the classical limit the single-particle observables are observed to relax toward a nonthermal stationary value. This phenomenon is known as violent relaxation and it is generally absent at the quantum-mechanical level, where single-particle observables exhibits long-lived oscillations. In this paper we explain this discrepancy by determining some very restrictive conditions that quantum single-site Hamiltonians should meet in order for the system to undergo relaxation. We thus check them by introducing a new model (the so-called $w$ model) which can exhibit dynamical phase transition among thermal behavior, persistent excitations, and violent relaxation. We also propose a way to implement it within light-matter coupling. We finally explain how the classical limit restore this behavior, thus showing that, even if the mean-field dynamics of quantum models is usually thought to be classical, quantum effects still play an important role in it.

Source: Physical review. B./Physical review. B

DOI: 10.1103/physrevb.111.214301

Authors: Guido Giachetti, Nicolò Defenu

Institutions: École Normale Supérieure - PSL, Laboratoire de Physique de l'Ecole Normale Supérieure, AREA Science Park, ETH Zurich

Language: English

Topic: Quantum many-body systems

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: European Commission, Deutsche Forschungsgemeinschaft, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Kavli Institute for Theoretical Physics, University of California, Santa Barbara

Awards: Out-of-equilibrium criticality of long-range interacting quantum systems, G3301826082, EXC 2181: STRUKTUREN: Emergenz in Natur, Mathematik und komplexen Daten, G7908743386