Wigner Function for Coherent Superposition of Two Squeezed States

Jun Song, Hong-Yi Fan

徐莉娟, 谭国斌, 马善钧 +1 more

The statistical properties of m-coherent superposition operation(μa + νa■)m on the single-mode squeezed vacuum state(M-SSVS) and its decoherence in 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.

Antoine Royer

Lijuan Xu, Guo-Bin Tan, Ma Shan-Jun +1 more

The statistical properties of m -coherent superposition operation (μ a + va † ) m on the single-mode squeezed vacuum state (M-SSVS) and its decoherence in 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.

Vladimír Bužek, P. L. Knight, A. Vidiella-Barranco

We investigate the nature of the quantum fluctuations in a light field created by the superposition of coherent fields. We give a physical explanation (in terms of Wigner functions and phase-space interference) why the 1-D superposition of coherent states in the direction of the x-quadrature leads to the squeezing of fluctuations in the y-direction, and show that such a superposition can generate the squeezed vacuum and squeezed coherent states.

Elsayed M. E. Zayed, A. S. Daoud, M A Al-Laithy +1 more