Non-Gaussian features from excited squeezed vacuum state

In this work, we introduce a non-Gaussian quantum state named excited squeezed vacuum state (ESVS), which can be utilized to describe quantum light field emitted from the multiphoton quantum process occurred in some restricted quantum systems. We investigate its nonclassical properties such as Wigner distribution in phase space, photon number distribution, the second-order autocorrelation and the quadrature fluctuations. By virtue of the methods of Hilbert–Schmidt distance and quantum relative entropy (QRE), we quantify the non-Gaussianity of the ESVS, respectively. Due to the similar photon statistics, we examine the fidelity between the ESVS and the photon-subtraction squeezed vacuum state (PSSVS), and then find the optimal fidelity by monitoring the relevant parameters. Considering a thermal lossy channel, we examine the evolution of Wigner function for the ESVS.