title: Experimental demonstration of entanglement-enhanced classical communication over a quantum channel with correlated noise.
abstract: We present an experiment demonstrating the entanglement enhanced capacity of a quantum channel with correlated noise, modeled by a fiber optic link exhibiting fluctuating birefringence. In this setting, introducing entanglement between two photons is required to maximize the amount of information that can be encoded into their joint polarization degree of freedom. We demonstrated this effect using a fiber-coupled source of entangled photon pairs based on spontaneous parametric down-conversion, and a linear-optics Bell state measurement. The obtained experimental classical capacity with entangled states is equal to 0.82+/-0.04 per a photon pair, and it exceeds approximately 2.5 times the theoretical upper limit when no quantum correlations are allowed.
authors.affiliation: Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: Konrad
authors.initials: K
authors.lastname: Banaszek
authors.forename: Andrzej
authors.initials: A
authors.lastname: Dragan
authors.forename: Wojciech
authors.initials: W
authors.lastname: Wasilewski
authors.forename: Czesław
authors.initials: C
authors.lastname: Radzewicz