Charge Fluctuations in the Edge States of N-S hybrid Nano-Structures

TL;DR

This paper develops a method to compute charge fluctuations in gated mesoscopic N-S hybrid structures, focusing on edge states under high magnetic fields, and compares equilibrium and non-equilibrium fluctuations.

Contribution

It introduces a calculation framework for charge fluctuations in edge states of N-S hybrid structures, including multi-edge state systems and different lead configurations.

Findings

Charge fluctuations depend on edge state number and lead configuration.

Equilibrium and non-equilibrium fluctuations show distinct behaviors.

Quantum point contact exhibits specific fluctuation characteristics.

Abstract

In this work we show how to calculate the equilibrium and non-equilibrium charge fluctuations in a gated normal mesoscopic conductor which is attached to one normal lead and one superconducting lead. We then consider an example where the structure is placed in a high magnetic field, such that the transport is dominated by edge states. We calculate the equilibrium and non-equilibrium charge fluctuations in the gate, for a single edge state, comparing our results to those for the same system, but with two normal leads. We then consider the specific example of a quantum point contact and calculate the charge fluctuations in the gate for more than one edge state.