Transport-based fusion that distinguishes between Majorana and Andreev bound states

TL;DR

This paper proposes a transport measurement protocol in a Majorana box system to distinguish topological Majorana bound states from nontopological Andreev bound states by analyzing charge transmission during controlled tunneling switches.

Contribution

It introduces a novel fusion protocol based on transport measurements that can differentiate Majorana from Andreev bound states using simple current measurements and gate control.

Findings

The protocol reveals different charge transmission signatures for Majorana and Andreev states.

It enables measurement of Majorana fusion rules through DC current analysis.

The method requires only fast gate control and DC current measurement.

Abstract

It has proven difficult to distinguish between topological Majorana bound states and nontopological Andreev bound states and to measure the unique properties of the former. In this work, we aim to alleviate this problem by proposing and theoretically analyzing a new type of fusion protocol based on transport measurements in a Majorana box coupled to normal leads. The protocol is based on switching between different nanowire pairs being tunnel coupled to one of the leads. For a Majorana system, this leads to switching between different states associated with parity blockade. The charge being transmitted at each switch provides a measurement of the Majorana fusion rules. Importantly, the result is different for a system with nontopological Andreev bound states. The proposed protocol only requires measuring a DC current combined with fast gate-control of the tunnel couplings.