Deterministic Frequency-Based Polarization Entanglement Concentration with the Multipartite Less-Hyperentangled State

A deterministic entanglement concentration protocol (ECP) is demonstrated in a multipartite less-hyperentangled system, containing the simultaneous entanglements in polarization and frequency degrees of freedom. The motivation is that the entangled system in frequency degree of freedom suffers little from the effects of the channel noise in optical fibers. Consequently, a maximally entangled system can be generated in polarization degree of freedom from the multipartite less-hyperentangled system with cross-Kerr nonlinearity. Compared with the conventional ECPs that have success probabilities less than one while iterating their recursive entanglement concentration processes several times to achieve a maximally entangled system in polarization degree of freedom, the present ECP can generate a maximally entangled system in polarization degree of freedom in two steps with a certainty. It may be useful for enhancing the efficiency of communications in long-distance quantum computation networks.