Loss of non-Gaussianity for damped photon-subtracted thermal states

Abstract

Abstract. We investigate non-Gaussianity properties for a set of classical one-mode states obtained by subtracting photons from a thermal state. Three distance-type degrees of non-Gaussianity used for these states are shown to have a monotonic behaviour with respect to their mean photon number. Decaying of their nonGaussianity under damping is found to be consistently described by the distancetype measures considered here. We also compare the dissipative evolution of nonGaussianity when starting from M -photon-subtracted and M -photon-added thermal states.

Non-Gaussianity of multiple photon-subtracted thermal states in terms of compound-Poisson photon number distribution parameters: theory and experiment

“…Thus, we have shown, how the several measures of non-Gaussianity depend on the parameters of MPSTS: mean photon number µ and coherence parameter a . Here we would like to highlight the kurtosis-based measure, which on the one hand have a simple analytical dependency on µ and a (12), and on the other hand can be directly calculated from the measured quadrature histograms without quantum state reconstruction procedure (14). It has been shown theoretically and validated experimentally that MPSTSs lose their non-Gaussianity during the optical damping.…”

“…, MPSTS a n a n n a n P n n n a n P n a a n a a µ µ µ µ µ In quantum mechanics the evolution of the density matrix under the action of losses can be obtained by solving the quantum-optical master equation [20]. In paper [12] the photon number distribution for damped MPSTS was obtained by interaction during the time t with a thermal reservoir with a mean photon number R In other words, optical losses don't change the coherence parameter a of MPSTS, but decrease the mean photon number µ according to the transmission coefficient.…”

“…For the quantitative description of non-Gaussianity of MPSTSs, it is possible to introduce measures based on the distance between the density matrix One such measure is the Gilbert-Schmidt metric introduced to measure of non-Gaussianity in [21][22][23] and applied to the MPSTSs analysis in [12]:…”

“…a Gaussian state. One should note that expression (5) can be represented in an analytical form [12]. (7), K δ -the measure based on the kurtosis of the quadrature distribution (12).…”

“…One should note that expression (5) can be represented in an analytical form [12]. (7), K δ -the measure based on the kurtosis of the quadrature distribution (12). Arrows correspond to the evolution trajectories for 1, 2, 3, 4 and 5-photon subtracted thermal states measured in the experiment.…”