Optimal entanglement concentration for quantum dot and optical microcavities systems

TL;DR

This paper introduces an optimized entanglement concentration protocol for electron pairs in quantum dot and microcavity systems, requiring only one photon passing through a single microcavity, thus improving success probability and practicality.

Contribution

It presents a more efficient entanglement concentration method using only one photon and one microcavity, enhancing success probability over previous protocols.

Findings

Protocol requires only one photon passing through one microcavity.

Success probability can be increased by repeating the protocol.

Feasible with current technology for quantum communication.

Abstract

A recent paper [Chuan Wang, Phys. Rev. A \textbf{86}, 012323 (2012)] discussed an entanglement concentration protocol (ECP) for partially entangled electrons using a quantum dot and microcavity coupled system. In his paper, each two-electron spin system in a partially entangled state can be concentrated with the assistance of an ancillary quantum dot and a single photon. In this paper, we will present an optimal ECP for such entangled electrons with the help of only one single photon. Compared with the protocol of Wang, the most significant advantage is that during the whole ECP, the single photon only needs to pass through one microcavity which will increase the total success probability if the cavity is imperfect. The whole protocol can be repeated to get a higher success probability. With the feasible technology, this protocol may be useful in current long-distance quantum communications.