Concentration and purification scheme for two partially entangled photon pairs - art. no. 012304

An experimental scheme for concentrating entanglement in partially entangle d photon pairs is proposed. In this scheme, two separated parties obtain on e maximally entangled photon pair from two previously shared partially enta ngled photon pairs by local operations and classical communication. A pract ical realization of the proposed scheme is discussed, which uses imperfect photon detectors and spontaneous parametric down-conversion as a photon sou rce. This scheme also works for purifying a class of mixed states.