2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/93817Quantum 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, 1998Quantum Physicstext