Parity-locking effect in a strongly-correlated ring

TL;DR

This paper investigates how strong electron-electron interactions in a multichannel ring cause the magnetic response to become uniformly diamagnetic or paramagnetic, depending solely on the total electron count, regardless of disorder.

Contribution

It reveals a parity-locking effect in strongly correlated rings, showing a unified magnetic response independent of individual channel contributions.

Findings

Strong correlations lead to a uniform magnetic response

Parity-locking effect is robust against disorder

Response depends only on total electron number

Abstract

Orbital magnetism in an integrable model of a multichannel ring with long-ranged electron-electron interactions is investigated. In a noninteracting multichannel system, the response to an external magnetic flux is the sum of many diamagnetic and paramagnetic contributions, but we find that for sufficiently strong correlations, the contributions of all channels add constructively, leading to a parity (diamagnetic or paramagnetic) which depends only on the total number of electrons. Numerical results confirm that this parity-locking effect is robust with respect to subband mixing due to disorder.