Quasiprobability distributions and the analysis of the linear quantum channel with thermal noise

摘要: The quasiprobability distributions (QPD) introduced by Cahill and Glauber much simplify calculating the density operator of output a linear quantum channel from input when attenuates is corrupted thermal noise. This models, for instance, an attenuator viewed as simple harmonic oscillator in contact with heat bath, or relation between radiating field mode aperture transmitter it excites at distant receiver. It shown how attenuation noise modify dependence QPD on ordering parameter s. form indicates that greater attenuation, more nearly state resembles classical state. Indeed, addition contributing average only one photon suffices to convert arbitrary unimodal into principal result paper applied determining whose generalized coherent