Wigner operator and squeezing for rotated quadrature phases

We introduce the Wigner operator <(Delta)over cap (theta)>(x, p) for the rotated quadrature phases and use the technique of integration within an ordered product of operators to derive its explicitly simpler form. Based on this, the mutual relations between <(Delta)over cap (theta)>(x, p) and the corresponding marginal probability distribution operator can be easily revealed. The Wigner function theory is thus be recasted into a more elegant and concise formalism. The squeezing in rotated quadrature phase is discussed with the same method.