Wigner functions of two-mode excited squeezed vacuum states

Using the Wigner operator in the entangled-state representation we construct the Wigner functions of the two-mode excited squeezed vacuum states (TESVS). In term of the variations of the Wigner functions with respect to the parameters m, n and r in the ρ-γ phase space, the quantum interference properties and squeezing effects of the TESVS are discussed. The results show that, for different values of m and n, the TESVS have different quantum interference effects, however for different squeezing parameters r the TESVS exhibit different squeezing effects. Furthermore, the physical meaning of the Wigner functions is identified according to the marginal distributions of the Wigner functions for the TESVS.