Illustration of the dynamical Casimir Effect.
Quantum field theory (QFT) predicts that an oscillating uncharged mirror in free space (vacuum) generates electromagnetic radiation (photons), i.e., it shines. This effect does not have an analogue in classical physics, where all electromagnetic radiation is generated by moving charges (e.g., electrons). The photon creation process predicted by QFT is due to the interaction between the time-dependent boundary condition, imposed by the moving mirror, and the quantum mechanical vacuum fluctuations. Kinetic energy of the moving mirror is transferred to the electromagnetic field due to this interaction, and virtual vacuum photons are upconverted to real photons that propogates away from the mirror.
The dynamical Casimir effect has a solid theoretical foundation, but it has not yet been observed in experiments. The main reason is the experimental difficulties in moving the mirror sufficiently fast to generate a detectable amount of photons. However, in recent years realistic experimental proposals have been presented, and experimental verification of the dynamical Casimir effect is likely within the near future.
