Nature of eigenstates in a mesoscopic ring coupled to a side branch

TL;DR

This paper investigates the eigenstates and persistent currents in a multichannel mesoscopic ring with a side branch, revealing nonmagnetic states and persistent current behavior distinct from continuum models.

Contribution

It formalizes the parity effect in a multichannel ring with a side branch using a tight binding model, highlighting differences from continuum models and identifying nonmagnetic states.

Findings

Persistent current does not change sign over large fluctuations in particle number.

Some eigenstates can be nonmagnetic.

Tight binding results differ slightly from continuum model predictions.

Abstract

We formalize the parity effect of a multichannel ring coupled to a side branch using the tight binding model. We find that the tight binding model gives slightly different result from the continuum model. We also show that some states of the system can be nonmagnetic. In the multichannel ring coupled to a side branch, the persistent current in the ring does not change sign, over gigantic fluctuations in N (the number of particles in the ring).