Transport Across an Impurity in One Dimensional Quantum Liquids Far From Equilibrium

We study the effect of a single impurity on the transport properties of a one dimensional quantum liquid highly excited away from its ground state by a sudden quench of the bulk interaction. In particular we compute the time dependent dc current to leading order in the impurity potential, using bosonization and starting both from the limit of a uniform system and from the one of two decoupled semi-infinite systems. Our results reveal that the nonequilibrium excitation of bulk modes induced by the global quench has important effects on the conductor-insulator quantum phase transition, which turns into a crossover for any small quench amplitude. In addition, the dynamics of the current displays a faster decay towards the steady-state as compared to the equilibrium case, a signature of quench-induced decoherence.