Persistent Current in Normal Metals

Abstract

We discuss the recent experiments on persistent current in metallic rings in the backdrop of low temperature decoherence. The observed size of the persistent current, typically on the order of the Thouless energy, $ e/τ_D$, is much larger than the theoretical results, obtained with or without electron interaction. In considering the phenomenology of both decoherence and persistent current, usually observed in similar systems, we argue towards a dynamic role played by decoherence in the generation of a persistent current. A field-induced phase shift from near-equilibrium high-frequency fluctuations---which otherwise gives rise to decoherence---under certain conditions of periodicity and asymmetry due to disorder, is argued to induce a steady state diffusion current on the order of $e/τ_D$, comparable to the observed persistent current.