Comments on parametric creation of photons in model cosmological problems

Model cosmological problems include studies of creation of real particles (photons) from vacuum during motion of mirrors in a space-time region free of all nongravitational fields. It is shown that this process is equivalent to parametric generation or amplification of light under zero initial conditions, i.e., it is equivalent to parametric amplification of zero-point vibrations of vacuum on a moving mirror acting against Casimir radiation pressure forces.