Universal thermal and electrical transport near the superconductor-metal quantum phase transition in nanowires

TL;DR

This paper investigates thermal and electrical conductivities in nanowires near the superconductor-metal quantum phase transition, proposing a field theory for quantum criticality and analyzing deviations in the Wiedemann-Franz ratio.

Contribution

It introduces a theoretical framework for understanding quantum critical transport in nanowires, focusing on deviations from classical laws and phase crossovers.

Findings

Deviations in the Wiedemann-Franz ratio from the Lorenz number.

Description of crossovers from quantum critical to metallic and superconducting phases.

A field theory model for quantum criticality in quasi-one-dimensional wires.

Abstract

We describe the thermal and electrical conductivities of quasi-one dimensional wires, across a quantum phase transition from a superconductor to a metal induced by pairbreaking perturbations. Fluctuation corrections to BCS theory motivate a field theory for quantum criticality. We describe deviations in the Wiedemann-Franz ratio from the Lorenz number, which can act as sensitive tests of the theory. We also describe the crossovers out of the quantum critical region into the metallic and superconducting phases.