Finite-temperature fluid–insulator transition of strongly interacting 1D disordered bosons

Significance One-dimensional bosons in disorder provide a perfect system for studying a generic phenomenon of many-body localization–delocalization transition. After the observation of single-particle Anderson localization in dilute clouds of bosonic atoms, the obvious direction of research is to describe the effects of repulsion between the bosons. Theoretical studies of 1D interacting bosons have a long history. In the case of strong enough repulsion and zero temperature, the problem was solved by Giamarchi and Schulz in 1988, and, more recently, the limit of weak repulsion was analyzed. However, the full picture of finite temperature and arbitrary interaction strength has remained an open problem. In this paper, we develop such a theory and establish predictions that can be confronted to experiment. We consider the many-body localization–delocalization transition for strongly interacting one-dimensional disordered bosons and construct the full picture of finite temperature behavior of this system. This picture shows two insulator–fluid transitions at any finite temperature when varying the interaction strength. At weak interactions, an increase in the interaction strength leads to insulator → fluid transition, and, for large interactions, there is a reentrance to the insulator regime. It is feasible to experimentally verify these predictions by tuning the interaction strength with the use of Feshbach or confinement-induced resonances, for example, in 7Li or 39K.