Realignment Entanglement Criterion for Continuous Bipartite Symmetric   Quantum States
  The separability of bipartite non-Gaussian states is studied by applying the realignment criterion with the technique of functional analysis. The realignment criterion is given as one inequality in contrast to the infinitive number of inequalities based on the moments. We give the necessary and sufficient condition of inseparability for non-Gaussian states prepared by photon subtraction or addition from symmetric Gaussian states. The entanglement criterion of non-Gaussian states evolved in thermal noise and amplitude damping environment is also obtained. 
Xiao-yu Chen, Li-zhen Jiang, Ping Yu, Mingzhen Tian
quant-ph