Transformations of the nonclassical states by an optical amplifier

Abstract

We consider nonclassical properties of the field at the output of an amplifier under the operational condition that the output exhibits neither squeezing nor sub-Poissonian statistics but has the nonclassical P function. We also present explicit results for the output P function when the input is strictly a quantum-mechanical state similar to a Fock state. The nonclassical properties of the marginal distribution associated with the output are derived. The domain where the marginal distribution remains nonclassical is different from the domain over which the output P function is nonclassical. The amplifier is shown to be a useful device for direct measurements of the quasiprobabilities.