Giant optical Faraday rotation induced by a single electron spin in a quantum dot: Applications to entangling remote spins via a single photon

TL;DR

This paper introduces a method using giant Faraday rotation to detect single electron spins in quantum dots, enabling scalable entanglement of remote spins via a single photon, with potential applications in quantum information processing.

Contribution

It proposes a novel quantum non-demolition spin detection technique based on giant Faraday rotation in a microcavity, facilitating scalable entanglement schemes.

Findings

Giant and tunable Faraday rotation observed in quantum dot-microcavity systems.

Single-photon mediated entanglement scheme for remote spins.

Potential for experimental implementation in quantum networks.

Abstract

We propose a quantum non-demolition method - giant Faraday rotation - to detect a single electron spin in a quantum dot inside a microcavity where negatively-charged exciton strongly couples to the cavity mode. Left- and right-circularly polarized light reflected from the cavity feels different phase shifts due to cavity quantum electrodynamics and the optical spin selection rule. This yields giant and tunable Faraday rotation which can be easily detected experimentally. Based on this spin-detection technique, a scalable scheme to create an arbitrary amount of entanglement between two or more remote spins via a single photon is proposed.