J. Daboul et al., GENERAL-SOLUTIONS OF THE PSEUDO-DIFFUSION EQUATION OF SQUEEZED STATES, Journal of physics. A, mathematical and general, 28(16), 1995, pp. 4623-4637
We show that the projection operator \pq; ye(i phi)][ye(i phi); pq\, w
here \pq; ye(i phi)] is a squeezed stare, obeys a partial differential
equation in which the squeeze parameter y plays the role of time. It
follows that related functions, such as the probability distribution f
unctions and the Wigner function are solutions of this equation. This
equation will be called a pseudo-diffusion equation, because it resemb
les a diffusion equation in Minkowski space. We give general solutions
of the pseudo-diffusion equation, first by the method of separation o
f variables and then by the Fourier transform method, and discuss the
limitations of the latter method. The Fourier method is used to introd
uce squeezing into the number states, the thermal light and the Wigner
function.