Nonclassicality and decoherence of the coherent superposition operation of photon subtraction and addition on the squeezed state

摘要

The statistical properties of m-coherent superposition operation (μa + va+)m on the single-mode squeezed vacuum state (M-SSVS) and its decoherence iu a thermal environment are studied.Converting the M-SSVS to a squeezed Hermite polynomial excitation state,we obtain a compact expression for the normalization factor of M-SSVS,which is the Legendre polynomial of the squeezing parameter.We also derive the explicit expression of the Wigner function (WF) of the M-SSVS,and find the negative region of the WF in phase space.The decoherence effect on this state is then discussed by deriving the time evolution of the WF.Using the negativity of the WF,the loss of nonclassicality is then discussed.