Interaction-Induced Enhancement and Oscillations of the Persistent Current

TL;DR

This paper investigates how interactions in multichannel rings cause persistent currents to oscillate and significantly increase, with strong interactions leading to a giant enhancement due to correlated channel contributions.

Contribution

It reveals interaction-induced oscillations and enhancement of persistent currents in multichannel rings, highlighting a robust parity-locking effect confirmed by numerical analysis.

Findings

Persistent current oscillates in sign with interaction strength.

Strong interactions lead to a giant enhancement of the current.

Parity-locking effect is robust against disorder.

Abstract

The persistent current $I$ in integrable models of multichannel rings with both short- and long-ranged interactions is investigated. $I$ is found to oscillate in sign and increase in magnitude with increasing interaction strength due to interaction-induced correlations in the currents contributed by different channels. For sufficiently strong interactions, the contributions of all channels are found to add constructively, leading to a giant enhancement of $I$. Numerical results confirm that this parity-locking effect is robust with respect to subband mixing due to disorder.