Interferometric resonance signatures of Majorana bound states

TL;DR

This paper predicts distinctive resonance peaks in current noise and conductance spectra caused by Majorana bound states in a nanoscopic interferometer, aiding their experimental detection.

Contribution

It introduces a theoretical framework linking resonance signatures in noise and conductance to Majorana bound states in a nanostructure.

Findings

Resonance peaks depend on Zeeman splitting and tunneling parameters.

Unitary limit peak of 2e^2/h at zero voltage observed.

Resonance peaks appear at voltages matching the spin-related frequencies.

Abstract

We calculate the current noise power spectrum in a nanoscopic interferometer consisting of a Majorana bound state (MBS) and a localized spin. We show that for large voltage (though less than the superconducting gap) several strong resonance peaks appear at frequencies that depend on the Zeeman splitting of the localized spin and on its tunneling to the localized spin. We also evaluate the differential conductance and find the unitary limit peak $2e^2/h$ at zero voltage as well as peaks at voltages corresponding to the resonances. We propose that detection of the resonances and related peaks in the differential conductance provide a strong support for the presence of an MBS.