Year: 2000
Type: article
Abstract: A scheme to achieve dense quantum coding for the quadrature amplitudes of the electromagnetic field is presented. The protocol utilizes shared entanglement provided by nondegenerate parametric down-conversion in the limit of large gain to attain high efficiency. For a constraint in the mean number of photons $\mathrm{n\ifmmode \bar{}\else \={}\fi{}}$ associated with modulation in the signal channel, the channel capacity for dense coding is found to be $\mathrm{ln}(1+\mathrm{n\ifmmode \bar{}\else \={}\fi{}}+{n}^{2}),$ which always beats coherent-state communication and surpasses squeezed-state communication for $\mathrm{n\ifmmode \bar{}\else \={}\fi{}}>1.$ For $\mathrm{n\ifmmode \bar{}\else \={}\fi{}}\ensuremath{\gg}1,$ the dense coding capacity approaches twice that of either scheme.
Source: Physical Review A
Authors: Samuel L. Braunstein, H. J. Kimble
Institutions: Bangor University, California Institute of Technology
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2019004690