Probing the existence and dynamics of Majorana fermion via transport through a quantum dot

TL;DR

This paper proposes an experimentally feasible setup with a quantum dot and nanowire to detect Majorana fermions through transport measurements, revealing their zero-energy nature and coherent dynamics.

Contribution

It introduces a method to identify Majorana fermions via current subtraction and shot noise analysis in a quantum dot-nanowire system, providing analytic tools for experimental parameter extraction.

Findings

Current subtraction reveals Majorana zero-energy signature.

Shot noise spectral dip indicates Majorana coherent oscillations.

Analytic formulas enable experimental parameter estimation.

Abstract

We consider an experimentally feasible setup to demonstrate the existence and coherent dynamics of Majorana fermion. The transport setup consists of a quantum dot and a tunnel-coupled semiconductor nanowire which is anticipated to generate Majorana excitations under some conditions. For transport under finite bias voltage, we find that a subtraction of the source and drain currents can expose the essential feature of the Majorana fermion, including the zero-energy nature by gate-voltage modulating the dot level. Moreover, coherent oscillating dynamics of the Majorana fermion between the nanowire and the quantum dot is reflected in the shot noise via a spectral dip together with a pronounced zero-frequency noise enhancement effect. Important parameters, e.g. for the Majorana's mutual interaction and its coupling to the quantum dot, can be extracted out in experiment using the derived analytic results.