Entanglement Criterion for Coherent Subtraction and Coherent Addition   Bipartite Continuous variable States
  Photon subtraction and addition are experimental means of generating non-Gaussian states from Gaussian states. Coherent subtraction or addition is a combination of photon subtractions or additions. The resultant states are quite general non-Gaussian states. The states can be photon number entangled states with arbitrary coefficients. We derive the entanglement conditions for several classes of coherent subtraction or coherent addition bipartite continuous variable states. One of the entanglement conditions is necessary and sufficient. 
Li-zhen Jiang, Xiao-yu Chen, Tian-yu Ye, Fang-yu Hong
quant-ph