Finite-frequency noise in a topological superconducting wire

TL;DR

This paper investigates the finite-frequency current cross-correlations in topological superconducting nanowires, revealing unique signatures of Majorana bound states through vanishing cross-correlations at high frequencies, supported by analytic and numerical models.

Contribution

It demonstrates that Majorana bound states cause distinctive high-frequency cross-correlation signatures, contrasting with ordinary Andreev bound states, using both analytic and tight-binding models.

Findings

Vanishing cross-correlations above twice the applied voltage frequency

Confirmation of results with realistic tight-binding models

Finite-temperature effects influence the cross-correlation behavior

Abstract

In this paper we study the finite-frequency current cross-correlations for a topological superconducting nanowire attached to two terminals at one of its ends. Using an analytic 1D model we show that the presence of a Majorana bound state yields vanishing cross-correlations for frequencies larger than twice the applied transport voltage, in contrast to what is found for a zero-energy ordinary Andreev bound state. Zero cross-correlations at high frequency have been confirmed using a more realistic tight-binding model for finite-width topological superconducting nanowires. Finite-temperature effects have also been investigated.