Sending Quantum Information with Gaussian States

Abstract

Quantum information characteristics, such as quantum mutual information, loss, noise and coherent information are explicitly calculated for Bosonic attenuation/amplification channel with input Gaussian state. The coherent information is shown to be negative for the values of the attenuation coefficient $k<1/\sqrt{2}$.

11 pages, Latex, 2 eps figures. To appear in Proceedings of the 4th International Conference on Quantum Communication, Measurement and Computing, Evanston, August 22-27, 1998