Eigenstate thermalization to non-monotonic distributions in strongly-interacting chaotic lattice gases

TL;DR

This paper demonstrates the emergence of non-monotonic energy distributions in strongly-interacting chaotic lattice gases, challenging traditional thermal distribution models, with implications for cold atom experiments.

Contribution

It reveals non-monotonic equilibrium energy distributions in many-body chaotic systems with finite spectra, supported by exact diagonalization of Fermi-Hubbard and Bose-Hubbard models.

Findings

Non-monotonic energy distributions observed in models.

Supports both positive and negative temperatures.

Results applicable to cold atom experiments.

Abstract

We find non-monotonic equilibrium energy distributions, qualitatively different from the Fermi-Dirac and Bose-Einstein forms, in strongly-interacting many-body chaotic systems. The effect emerges in systems with finite energy spectra, supporting both positive and negative temperatures, in the regime of quantum ergodicity. The results are supported by exact diagonalization calculations for chaotic Fermi-Hubbard and Bose-Hubbard models, when they have Wigner-Dyson statistics of energy spectra and demonstrate eigenstate thermalization. The proposed effects may be observed in experiments with cold atoms in optical lattices.