  An alternative approach to the Jaynes-Cummings model (JCM) with dissipation
at a finite enviromental temperature is presented in terms of a new master
equation under Born-Markovian approximations. An analytic solution of the
dissipation JCM is obtained. A variety of physical quantities of interest are
calculated analytically. Dynamical properties of the atom and the field are
investigated in some detail. It is shown that both cavity damping and
environmental temperature strongly affect nonclassical effects in the JCM, such
as collapse and revivals of the atomic inversion, oscillations of the
photon-number distribution, quadrature squeezing of the field and
sub-Poissonian photon statistics.
