Fingerprints of Majorana bound states in Aharonov Bohm geometry

TL;DR

This paper proposes a method to distinguish Majorana bound states from Andreev bound states using flux-dependent conductance anti-correlation in an Aharonov-Bohm ring, providing a unique signature for Majorana states.

Contribution

The study introduces a flux-based conductance measurement technique that uniquely identifies Majorana bound states by their anti-correlated resonance behavior, unlike Andreev bound states.

Findings

Resonance conductance quantized to 2e^2/h at certain flux values.

Anti-correlation in conductance as a function of flux is specific to Majorana bound states.

Phase sensitivity analysis distinguishes MBS from ABS based on tunneling amplitude phases.

Abstract

We study a ring geometry, coupled to two normal metallic leads, which has a Majorana bound state (MBS) embedded in one of its arm and is threaded by Aharonov Bohm ($\mathcal{A}\mathcal{B}$) flux $\phi$. We show that by varying the $\mathcal{AB}$ flux, the two leads go through resonance in an anti-correlated fashion while the resonance conductance is quantized to $2 e^2/h$. We further show that such anti-correlation is completely absent when the MBS is replaced by an Andreev bound state (ABS). Hence this anti-correlation in conductance when studied as a function of $\phi$ provides a unique signature of the MBS which cannot be faked by an ABS. We contrast the phase sensitivity of the MBS and ABS in terms of tunneling conductances. We argue that the relative phase between the tunneling amplitude of the electrons and holes from either lead to the level (MBS or ABS), which is constrained to $0,\pi$ for the MBS and unconstrained for the ABS, is responsible for this interesting contrast in the $\mathcal{AB}$ effect between the MBS and ABS.