With use of the coordinate representation of the one-mode squeeze operator, the coordinate representation wave function of the one-mode squeezed state is simply rederived. A parallel treatment for the two-mode squeeze operator yields the two-mode squeezed state wave function.
We obtain the wave function in the coordinate representation of the one-mode squeezed states \ensuremath{\Vert}\ensuremath{\zeta}, \ensuremath{\alpha}〉=exp(\ensuremath{\zeta}${\mathit{a}}^{\mathrm{^}2}$-${\mathrm{\ensuremath{\zeta}}}^{\mathrm{*}}$a2)exp(\ensuremath{\alpha}${\mathit{a}}^{\mathrm{^}}$-${\mathrm{\ensuremath{\alpha}}}^{\mathrm{*}}$a)\ensuremath{\Vert}0〉. The wave function is a displaced Gaussian with center and width depending upon the parameters \ensuremath{\alpha} and \ensuremath{\zeta}.
Coordinate wave functions for the one-mode squeezed states produced by the quantum analog of the general linear transformation in phase space are calculated. The probability density [\ensuremath{\Vert}\ensuremath{\psi}(q)${\ensuremath{\Vert}}^{2}$] for these states is Gaussian with center predicted by the classical transformation. The quantum image (which includes the traditional two-mode squeeze operator) of a three-parameter symplectic map in two-mode phase space equally generates squeezed states having Gaussian \ensuremath{\Vert}\ensuremath{\psi}(q1,q1)${\ensuremath{\Vert}}^{2}$. The center of the two-mode Gaussian is again predicted by the classical mapping.
We find that the exponential operators U=exp[-i(${\ensuremath{\lambda}}_{1}$Q1P2+${\ensuremath{\lambda}}^{2}$Q2P1] and W=exp[-i(${\ensuremath{\lambda}}_{1}$Q1Q2-${\ensuremath{\lambda}}_{2}$pP1P2)] (where ${\ensuremath{\lambda}}_{1}$ and ${\ensuremath{\lambda}}_{2}$ are real; Pi and Qi are coordinate and momentum operators, respectively; and i=1,2) are two types of generalized squeezing operators responsible for generating two types of one- and two-mode combination squeezed states, respectively. The coordinate and/or momentum representations of U and W are presented, and their normal product forms are first derived in terms of the newly developed technique of integration within an ordered product, which provides us with a direct approach to constructing these new squeezed states. The fluctuations in quadrature phases for these states are analyzed.
We introduce the coordinate-dependent one- and two-mode squeezing transformations and discuss the properties of the corresponding one-and two-mode squeezed states. We show that the coordinate-dependent one-and two-mode squeezing transformations can be constructed by the combination of two transformations, a coordinate-dependent displacement followed by the standard squeezed transformation. Such a decomposition turns a nonlinear problem into a linear one because all the calculations involving the nonlinear one- and two-mode squeezed transformation have been shown to be able to reduce to those only concerning the standard one- and two-mode squeezed states.