Persistent Current in Normal Metals

TL;DR

This paper explores the phenomenon of persistent current in normal metallic rings, proposing that decoherence dynamics and high-frequency fluctuations can induce steady state currents larger than traditional theories predict.

Contribution

It introduces a new phenomenological model linking decoherence and high-frequency fluctuations to the generation of persistent currents in metals.

Findings

Persistent currents are larger than theoretical predictions.

Decoherence and high-frequency fluctuations can induce steady state currents.

A dynamic role of decoherence in persistent current generation is proposed.

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/\tau_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 $e/\tau_D$, comparable to the observed persistent current.