Nicolas Dupuis

    LPTMC, Sorbonne University

    Finite-temperature phase diagram of the 1D disordered Bose gas

    In a one-dimensional Bose gas, disorder can induce a transition from a superfluid state (a Luttinger liquid) to a localized phase known as the Bose glass. We determine the finite-temperature phase diagram using bosonization and the nonperturbative functional renormalization group (FRG). We discuss two scenarios, based on distinct truncations of the effective action. In the first scenario, the Bose glass is destabilized at any finite temperature, giving rise to a normal fluid. Nevertheless, a low-temperature glassy regime can be identified, in which disorder plays an important role on intermediate length and time scales. In the second scenario, below a temperature Tc, the RG flow exhibits a singularity at a finite value of the RG momentum scale. We propose that this singularity signals a lack of thermalization and the existence of a many-body localized phase for T