  This report presents an approach to the exact solutions of the time-dependent
Jaynes-Cummings (J-C) model without the rotating wave approximation (RWA). It
is shown that there is a squeezing-operator unitary transformation for relating
the J-C model without RWA and the one with RWA. Thus by using an appropriate
squeezing unitary transformation, the time-dependent J-C model without RWA can
be transformed into the one with RWA that has been exactly solved previously,
and based on this one can readily obtain the exact solutions of the
time-dependent Jaynes-Cummings (J-C) model without RWA. The approach presented
here also shows that we can treat these two kinds of time-dependent J-C models
(both with and without RWA) in a unified way.
