Dynamical Conductivity at the Dirty Superconductor-Metal Quantum Phase Transition

We study the transport properties of ultrathin disordered nanowires in the neighborhood of the superconductor-metal quantum phase transition. To this end we combine numerical calculations with analytical strong-disorder renormalization group results. The quantum critical conductivity at zero temperature diverges logarithmically as a function of frequency. In the metallic phase, it obeys activated scaling associated with an infinite-randomness quantum critical point. We extend the scaling theory to higher dimensions and discuss implications for experiments.FAPESP[2010/03749-4]CNPq[302301/2009-7]Research CorporationNational Science Foundation NSF[DMR-0339147]National Science Foundation NSF[DMR-0906566