The von Neumann entropy and quantum statistical features of a degenerate parametric amplifier system

Abstract

Using the theory of partition function and the operator ordering method, we obtain the normalized density operator that describes the degenerate parametric amplifier system, and present its theoretical generation scheme. Also, we analytically and numerically investigate the quantum statistical properties and von Neumann entropy. It is found that the frequency of signal light can weaken the nonclassicality and the von Neumann entropy of the new state, however the interaction between light and medium can enhance them. This work provides a theoretical basis for the measurement and application of quantum entropy in quantum information.