Seminarium Fizyki Materii Skondensowanej

We study a one-dimensional disordered Bose fluid using bosonization, the replica method and a nonperturbative functional renormalization-group approach. We find that the (localized) Bose-glass phase is described by a fully attractive strong-disorder fixed point characterized by a singular disorder correlator whose functional dependence assumes a cuspy form. We show that this reveals the glassy properties (pinning, ``shocks'' and ``avalanches'') of the Bose-glass phase due to the existence of metastable states, as well as the crucial role of quantum tunneling between different metastable configurations leading to the existence of rare superfluid regions.