  The spontaneous emission of photons from optical cavities and from trapped
atoms has been studied extensively in the framework of quantum optics.
Theoretical predictions based on the rotating wave approximation (RWA) are in
general in very good agreement with experimental findings. However, current
experiments aim at combining better and better cavities with large numbers of
tightly confined atoms. Here we predict an energy concentrating mechanism in
the behavior of such a composite quantum system which cannot be described by
the RWA. Its result is the continuous leakage of photons through the cavity
mirrors, even in the absence of external driving. We conclude with a discussion
of the predicted phenomenon in the context of thermodynamics.
