Nonlocal noise cross-correlation mediated by entangled Majorana fermions

TL;DR

This paper proposes a scheme to generate and control nonlocal noise cross correlations between quantum dots mediated by Majorana bound states, providing a potential experimental signature for Majorana fermions.

Contribution

It introduces a method to produce and tune nonlocal noise correlations via Majorana states, overcoming local reflection effects and enabling detection of Majorana fermions.

Findings

Positive and negative cross correlations are tunable by gate voltages.

Cross correlation persists at finite temperatures within a limited range.

Local Andreev reflections suppress cross correlation when multiple energy levels are involved.

Abstract

Due to their nonlocality, qubits nested in Majorana bound states may be the key to realize decoherence-free quantum computation. Majorana bound states could be achieved at the ends of a one-dimensional topological superconductor. However, when the bound states couple directly to electron reservoirs their nonlocal correlation is quenched by local Andreev reflections. Here we propose a scheme to generate nonlocal noise cross correlation between two well-separated quantum dots, mediated by a pair of Majorana bound states. Both positive and negative cross correlations can be obtained by tuning the gate voltages applied to the dots. Within a limited range of finite temperatures, the cross correlation is not suppressed by thermal fluctuations. Furthermore, we show how the local Andreev reflections suppress the noise cross correlation when multiple dot energy levels are coupled to the Majorana bound states. The measurable cross correlation is expected to serve as a sensitive indicator for the generation of Majorana fermions.