Universal superfluid transition and transport properties of two-dimensional dirty bosons (Orale)

Giuseppe Carleo, Guilhem Boéris, Markus Holzmann +1 more

Giuseppe Carleo, Guilhem Boéris, Markus Holzmann +1 more

Laurent Sanchez-Palencia

Giuseppe Carleo, Guilhem Boéris, Markus Holzmann +1 more

We study the phase diagram of two-dimensional, interacting bosons in the presence of a correlated disorder in continuous space, by using large-scale quantum Monte Carlo simulations at finite temperature. We show that the superfluid transition is strongly protected against disorder. It remains of the Berezinskii-Kosterlitz-Thouless type up to disorder strengths comparable to the chemical potential. Moreover, we study the transport properties in the strong disorder regime where a zero-temperature Bose-glass phase is expected. We show that the conductance exhibits a thermally activated behavior vanishing only at zero temperature. Our results point towards the existence of a Bose bad-metal phase as a precursor of the Bose-glass phase.

S. M. Girvin, Mats Wallin, Erik Schwartz Sørensen +1 more

In contrast to the case of free fermions which have all states localized in two dimensions, dirty, repulsively-interacting bosons exhibit a zero-temperature localization phase transition between superconducting and insulating states as disorder is increased. The conductivity σ* = g (2 e ) 2 / h at the quantum critical point is a universal critical amplitude analogous to the universal jump in superfluid density at the classical Kosterlitz-Thouless transition. Using numerical Monte Carlo methods we compute the value of g for disorder-tuned transitions with and without long-range Coulomb interactions. We argue that this model is relevant to experiments on superconducting thin films and Josephson junction arrays.

Nandini Trivedi, M. S. Makivić