Ergodicity breaking in a Bose-Hubbard trimer with disorder

Abstract

We explore quantum ergodicity and its breakdown in a system of bosons in an optical lattice with disorder. Specifically, we study a one-dimensional three-site lattice using the Bose-Hubbard model. We characterize integrability using statistics on the eigenstate energy distribution. We investigate ergodicity in the context of the eigenstate thermalization hypothesis (ETH). We find that for weak disorder, the system is ergodic and thermalization is present. Interestingly, at sufficiently strong disorder, ergodicity in the system is broken and the system fails to thermalize.