Theory of the pairbreaking superconductor-metal transition in nanowires (Q1009589)

This paper deals with the study of the transition between a superconductor and a metal in ultra-narrow wires. The description of the transition used in the present paper is a critical theory of strongly repulsive, fluctuating Cooper pairs, written in terms of a complex order parameter, overdamped by its coupling to a bath of unpaired fermions resulting from the presence of some type of pairbreaking interaction. The existence of the bath, imagined as a large number of unpaired electrons residing in the transverse conduction channels of the wire, leads to a long range interaction in imaginary time providing Ohmic dissipation in the form of a nonanalytic term in the effective action. It is also established that the ratio between the thermal and the electrical conductivity displays a linear temperature dependence, which implies that the Wiedemann-Franz law is obeyed.