The characteristic function and entanglement of optical evolution
Xiaoyu Chen · Journal of Physics B Atomic Molecular and Optical Physics · 2006
The master equation of the quantum optical density operator is transformed to the equation of the characteristic function. Parametric amplification and amplitude damping as well as phase damping are considered. The solution for the most general initial quantum state is obtained for parametric amplification and amplitude damping. The purity of the one-mode Gaussian system and the entanglement of the two-mode Gaussian system are studied.