Onset of many-body chaos and thermalization in finite systems of interacting particles

by Felix Izrailev (Instituto de Fisica, BUAP (Mexico))




We study analytically and numerically the onset of thermalization in isolated quantum systems with finite number of interacting Bose and Fermi particles. We show that the thermalization emerges due to strong quantum chaos quantified in terms of a chaotic structure of many-body eigenstates. We developed semi-analytical approach allowing one to describe generic features of the quench dynamics both before and after equilibration [1, 2]. One of the important predictions is an analytical estimate of an exponential time increase of a number of components of wave function in many-body representation, in dependence of the number of particles, strength of interaction and initial conditions. We also studied how the Bose-Einstein distribution emerges in time, thus demonstrating a creation of quantum correlations between the occupation numbers, in spite of the loss of the information about an initial excitation [3].

1. F. Borgonovi, F.M. Izrailev, and L.F. Santos, Exponentially fast dynamics of chaotic many-body systems, Phys. Rev. E 99 (2019) 010101(R).

2. S. Mailoud, F. Borgonovi, and F.M. Izrailev, Process of equilibration in many-body isolated systems: diagonal versus thermodynamic entropy, New J. Phys. 22 (2020) 083087.
3. F. Borgonovi and F.M. Izrailev, Emergence of correlations in the process of thermalization of interacting bosons, 99 (2019) 012115.