Edge-state Fabry-Perot interferometer as a high sensitivity charge detector

TL;DR

This paper proposes a high sensitivity charge detector based on an electronic Fabry-Perot interferometer in the quantum Hall regime, utilizing multiple reflections and spin entanglement to enhance measurement precision.

Contribution

It introduces a novel interferometer design for charge detection that leverages multiple reflections and spin entanglement to improve sensitivity and enable quantum-limited measurements.

Findings

High sensitivity achieved with small transmission point contacts

Sensitivity doubled using spin-entangled electrons

Tunable for quantum-limited measurement with different reflection probabilities

Abstract

We present a scheme for high sensitivity charge detection in the integer quantum Hall regime using two point contacts in a series. The setup is an electronic analog of an optical Fabry-Perot interferometer. We show that for small transmission through the point contacts the sensitivity of the interferometer is very high due to multiple reflections at the point contacts. The sensitivity can be further enhanced twice by using electrons in spin entangled state. We show that for point contacts having different reflection probabilities, the interferometer can be tuned for the quantum limited measurement.