Universal persistent currents in mesoscopic metal rings due to long-range Coulomb interactions

TL;DR

This paper predicts a universal average persistent current in mesoscopic metal rings caused by long-range Coulomb interactions, independent of disorder specifics, and suggests an experiment to verify this phenomenon.

Contribution

It introduces a universal current formula derived from classical electromagnetic energy, linking persistent currents to fundamental constants and ring capacitance.

Findings

Universal persistent current of order α e c / C₀ predicted

Similarity between persistent currents and conductance fluctuations identified

Proposed experimental test for the theory

Abstract

We calculate the average persistent current in a mesoscopic metal ring threaded by a magnetic flux in the diffusive regime. It is shown that the classical electromagnetic energy leads to a {\it{universal}} average current of the order of $ \alpha e c / C_{0}$, where $\alpha$ is the fine structure constant, $-e$ is the charge of the electron, $c$ is the velocity of light, and $C_{0}$ is the classical capacitance of the ring. Striking similarities between persistent currents and universal conductance fluctuations are discovered. We suggest a simple experiment to test our theory.