Shot noise in a Majorana fermion chain

TL;DR

This paper calculates shot noise in Majorana fermion networks, revealing quantized Fano factors and enhanced conductance as signatures of Majorana bound states, with implications for quantum transport.

Contribution

It provides a detailed analysis of shot noise and conductance in various Majorana bound state network configurations, highlighting new quantization phenomena.

Findings

Fano factor is quantized at 2 when one Majorana is coupled to the lead.

Conductance and shot noise are significantly stronger than in weakly coupled junctions.

Both MBS coupling configurations show distinct shot noise signatures.

Abstract

We calculate the shot noise power in a junction of a network of Majorana bound states (MBS) with a normal metal. These Majorana bound states are on the border of alternative ferromagnetic and superconducting regions at the quantum spin Hall insulator edge. We analyze different realization of MBS networks including a few isolated ones or in a chain allowing for the limit of weak and strong tunneling. The conductance, as well as the shot noise are considerably stronger than those of a weakly coupled normal-superconduting junction, being a hallmark of the MBS. We find that the Fano factor is quantized $F=2$ when one MBS member of a pair is coupled to the lead, however if both MBS members are coupled $F$ is non-integer.