  We show analytically that the collapse and revival in the population dynamics
of the atom-cavity coupled system under the rotating wave approximation (RWA),
valid only at very weak coupling, is an artifact as the atom-cavity coupling is
increased. Even the first-order correction to the RWA is able to bring about
the absence of the collapse in the dynamics of atomic population inversion
thanks to intrinsic oscillations resulting from the transitions between two
levels with the same atomic quantum number. The removal of the collapse is
valid for a wide range of coupling strengths which are accessible to current
experimental setups. In addition, based on our analytical results that greatly
improve upon the conventional RWA, even the strong-coupling power spectrum can
now be explained with the help of the numerically exact energy levels.
