Simultaneous amplification and non-symmetric amplitude damping of   two-mode Gaussian state
  The evolution of two-mode Gaussian state under symmetric amplification, non-symmetric damping and thermal noise is studied. The time dependent solution of the state characteristic function is obtained. The separability criterions are given for the final state of weak amplification as well as strong amplification. 
Xiao-yu Chen, Li-zhen Jiang, Ji-wu Chen