2004/02/29 by Jun Mizuno, Kentaro Wakui, Akira Furusawa +1
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physreva.71.012304
published as PHYSICAL REVIEW A 71, 012304 (2005) · 4 pages, 4 figures, submitted to Phys. Rev. A
arxiv created 2004/10/29 · arxiv updated 2009/12/01
We have experimentally realized the scheme initially proposed as quantum dense coding with continuous variables [Ban, J. Opt. B 1, L9 (1999), and Braunstein and Kimble, \pra61, 042302 (2000)]. In our experiment, a pair of EPR (Einstein-Podolski-Rosen) beams is generated from two independent squeezed vacua. After adding two-quadrature signal to one of the EPR beams, two squeezed beams that contain the signal were recovered. Although our squeezing level is not sufficient to demonstrate the channel capacity gain over the Holevo limit of a single-mode channel without entanglement, our channel is superior to conventional channels such as coherent and squeezing channels. In addition, optical addition and subtraction processes demonstrated are elementary operations of universal quantum information processing on continuous variables.