Current cross-correlation spectroscopy of Majorana bound states

TL;DR

This paper uses time-dependent transport theory to analyze electron traversal times in Majorana-supporting nanowires, providing a heuristic formula and connecting it to experimental verification methods.

Contribution

It introduces a method to extract traversal times from quantum noise and proposes a heuristic formula, aiding the distinction between genuine and spurious Majorana zero modes.

Findings

Traversal times scale linearly with nanowire length.

A heuristic formula accurately models traversal times.

Time-resolved measurements can distinguish genuine MZMs from spurious ones.

Abstract

The clock speed of topological quantum computers based on Majorana zero mode (MZM)-supporting nanoscale devices is limited by the time taken for electrons to traverse the device. We employ the time-dependent Landauer-B{\"u}ttiker transport theory for current cross-lead correlations in a superconducting nanowire junction hosting MZMs. From the time-dependent quantum noise, we are able to extract traversal times for electrons crossing the system. After demonstrating a linear scaling of traversal times with nanowire length, we present a heuristic formula for the traversal times which accurately captures their behaviour. We then connect our framework to a proposed experimental verification of this discriminant between spurious and genuine MZMs utilizing time-resolved transport measurements.