arXiv:1110.0059 · Physical Review A
Efficient multipartite entanglement purification with the entanglement link from a subspace
Fu‐Guo Deng
Abstract
We present an efficient multipartite entanglement purification protocol (MEPP) for $N$-photon systems in a Greenberger-Horne-Zeilinger state with parity-check detectors. It contains two parts. One is the conventional MEPP with which the parties can obtain a high-fidelity $N$-photon ensemble directly, similar to the MEPP with controlled-not gates. The other is our recycling MEPP in which the entanglement link is used to produce some $N$-photon entangled systems from entangled ${N}^{\ensuremath{'}}$-photon subsystems ($2\ensuremath{\leqslant}{N}^{\ensuremath{'}}<N$) coming from the instances which are just discarded in all existing conventional MEPPs. The entangled ${N}^{\ensuremath{'}}$-photon subsystems are obtained efficiently by measuring the photons with potential bit-flip errors. With these two parts, the present MEPP has a higher efficiency than all other conventional MEPPs.