  In a recent article [A. Kurcz et al., Phys. Rev. A 81, 063821 (2010)] we
predicted an energy concentrating mechanism in composite quantum systems. Its
result is a non-zero stationary state photon emission rate even in the absence
of external driving. Here we discuss the possible origin of the predicted
effect. We attribute it to the presence of a non-trivial interaction between
different system components and to repeated environment-induced photon
measurements.
