De sitter space and perpetuum mobile

The general arguments that any interacting nonconformal classical field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile is given. The arguments are based on the observation that massive free falling particles can radiate other massive particles on the classical level as seen by the free falling observer. The intensity of the radiation process is not zero even for particles with any finite mass, i. e., with a wavelength which is within causal domain. Hence, we conclude that either de Sitter space cannot exist eternally or that one can build a perpetuum mobile. © 2012 Pleiades Publishing, Ltd.