Condensed Matter Seminar Series

Title: Dissipation and Quantum Fluctuations in Mesoscopic Josephson Junction Arrays and Superconducting Nanowires

Gil Refael

California Institute of Technology

Thursday April 27,  11:30 am,  Room 298,  Physics Building

Abstract:  Superconductivity in mesoscopic systems is supressed by quantum fluctuations. Dissipation actually restores superconductivity  in such systems. This interplay, however, is not yet well understood.  Examples are that of the breakdown of superconductivity in low  dimensional superconductors, and in particular, the normal-to- superconducting transition observed in nanowires. In this talk we  present a new theory of the superconductor-metal transition of  resistively shunted junctions. This theory takes mesoscopic effects  into account using a phenomenological two-fluid model of  superconducting grains. Using this model, we describe transport  through a single grain, and a chain of grains connected by  resistively shunted Josephson junctions. Finally, we will consider  the possible concequences of our theory for superconducting nanowires.