title: Quantum mutual information capacity for high-dimensional entangled states.
abstract: High-dimensional Hilbert spaces used for quantum communication channels offer the possibility of large data transmission capabilities. We propose a method of characterizing the channel capacity of an entangled photonic state in high-dimensional position and momentum bases. We use this method to measure the channel capacity of a parametric down-conversion state by measuring in up to 576 dimensions per detector. We achieve a channel capacity over 7 bits/photon in either the position or momentum basis. Furthermore, we provide a correspondingly high-dimensional separability bound that suggests that the channel performance cannot be replicated classically.
authors.affiliation: Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA.
authors.forename: P Ben
authors.initials: PB
authors.lastname: Dixon
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Howland
authors.forename: James
authors.initials: J
authors.lastname: Schneeloch
authors.forename: John C
authors.initials: JC
authors.lastname: Howell