Optimal multi-photon entanglement concentration with the photonic Faraday rotation

TL;DR

This paper presents an improved entanglement concentration protocol for multi-photon GHZ states using photonic Faraday rotation, requiring fewer resources and allowing repeated operations for higher success probability.

Contribution

The proposed protocol simplifies entanglement concentration by using only one less-entangled state and an auxiliary photon, with enhanced efficiency and repeatability.

Findings

Requires only one less-entangled state and an auxiliary photon

Can be repeated for higher success probability

More efficient under practical conditions

Abstract

A recent paper (Phys. Rev. A \textbf{86}, 034305 (2012)) proposed an entanglement concentration protocol (ECP) for distilling one pair of maximally entangled multi-photon Greenberger-Horne-Zeilinger (GHZ) state from two pairs of less-entangled multi-photon states with the photonic Faraday rotation. In this paper, we put forward an improved ECP for arbitrary less-entangled multi-photon GHZ state. In the ECP, we only require one pair of less-entangled multi-photon state and one auxiliary photon, and the whole concentration process only requires local operations. Moreover, our ECP can be used repeatedly to further concentrate the less-entangled multi-photon state and obtain a higher success probability. If consider the practical operation and imperfect detection, our protocol is more efficient. This ECP may be useful in current quantum information processing.