Measurement of the full distribution of the persistent current in normal-metal rings

TL;DR

This study measures the full distribution of persistent currents in normal-metal rings, confirming theoretical predictions that the distribution is nearly Gaussian due to mesoscopic fluctuations.

Contribution

First experimental extraction of multiple cumulants of persistent current distribution in individual rings, validating theoretical models of mesoscopic fluctuations.

Findings

Distribution is nearly Gaussian, with cumulants close to zero.

Measurement demonstrates high sensitivity to mesoscopic fluctuations.

Results align with theoretical predictions for diffusive metallic rings.

Abstract

We have measured the persistent current in individual normal metal rings over a wide range of magnetic fields. From this data, we extract the first six cumulants of the single-ring persistent current distribution. Our results are consistent with the theoretical prediction that this distribution should be nearly Gaussian (i.e., that these cumulants should be nearly zero) for diffusive metallic rings. This measurement highlights the particular sensitivity of persistent current to the mesoscopic fluctuations within a single coherent volume.