Singlephotonassisted entanglement concentration of a multiphoton system in a partially entangled W state with weak crossKerr nonlinearity
Abstract
We propose a nonlocal entanglement concentration protocol (ECP) for $N$photon systems in a partially entangled W state, resorting to some ancillary single photons and the paritycheck measurement based on crossKerr nonlinearity. One party in quantum communication first performs a paritycheck measurement on her photon in an $N$photon system and an ancillary photon, and then she picks up the evenparity instance for obtaining the standard W state. When she obtains an oddparity instance, the system is in a lessentanglement state and it is the resource in the next round of entanglement concentration. By iterating the entanglement concentration process several times, the present ECP has the total success probability approaching to the limit in theory. The present ECP has the advantage of a high success probability. Moreover, the present ECP requires only the $N$photon system itself and some ancillary single photons, not two copies of the systems, which decreases the difficulty of its implementation largely in experiment. It maybe have good applications in quantum communication in future.
 Publication:

Journal of the Optical Society of America B Optical Physics
 Pub Date:
 June 2012
 DOI:
 10.1364/JOSAB.29.001399
 arXiv:
 arXiv:1208.0105
 Bibcode:
 2012JOSAB..29.1399D
 Keywords:

 Quantum Physics
 EPrint:
 7 pages, 3 figures