Modified entanglement purification scheme with doubly entangled photon state

TL;DR

This paper presents a modified entanglement purification scheme using doubly entangled photon states, enhancing efficiency and reducing initial fidelity requirements, thus making practical quantum communication more feasible.

Contribution

The authors improve Xiao et al.'s scheme by introducing a two-step process that corrects bit-flip errors and purifies phase-flip errors with higher efficiency and lower initial fidelity needs.

Findings

High purification efficiency achieved.

Lower initial fidelity required for effective purification.

Feasible for practical quantum communication applications.

Abstract

Recently Xiao et al. proposed a scheme for entanglement purification based on doubly entangled photon states (Phys. Rev. A 77(2008) 042315). We modify their scheme for improving the efficiency of entanglement purification. This modified scheme contains two steps, i.e., the bit-flip error correction and the entanglement purification of phase-flip errors. All the photon pairs in the first step can be kept as all the bit-flip errors are corrected. For purifying the phase-flip errors, a wavelength conversion process is needed. This scheme has the advantage of high efficiency and it requires the original fidelity of the entangled state wanted fay lower than other schemes, which makes it more feasible in a practical application.