Impact of eigenstate thermalization on the route to equilibrium
Abstract
The eigenstate thermalization hypothesis (ETH) and the theory of linear response (LRT) are celebrated cornerstones of our understanding of the physics of manybody quantum systems out of equilibrium. While the ETH provides a generic mechanism of thermalization for states arbitrarily far from equilibrium, LRT extends the successful concepts of statistical mechanics to situations close to equilibrium. In our work, we connect these cornerstones to shed light on the route to equilibrium for a class of properly prepared states. We unveil that, if the offdiagonal part of the ETH applies, then the relaxation process can become independent of whether or not a state is close to equilibrium. Moreover, in this case, the dynamics is generated by a single correlation function, i.e., the relaxation function in the context of LRT. Our analytical arguments are illustrated by numerical results for idealized models of randommatrix type and more realistic models of interacting spins on a lattice. Remarkably, our arguments also apply to integrable quantum systems where the diagonal part of the ETH may break down.
 Publication:

Physical Review E
 Pub Date:
 May 2019
 DOI:
 10.1103/PhysRevE.99.050104
 arXiv:
 arXiv:1805.11625
 Bibcode:
 2019PhRvE..99e0104R
 Keywords:

 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Strongly Correlated Electrons;
 Quantum Physics
 EPrint:
 5 pages, 4 figures (+ 6 pages, 2 figure)