De Sitter space and perpetuum mobile

TL;DR

This paper argues that classical interacting non-conformal fields in de Sitter space imply the possibility of a perpetuum mobile due to radiation by free-falling particles, challenging the eternal stability of de Sitter space.

Contribution

It presents a general argument linking classical field interactions in de Sitter space to the theoretical possibility of perpetual motion machines.

Findings

Massive free-falling particles radiate in de Sitter space.

Radiation intensity remains non-zero for finite mass particles.

Either de Sitter space is not eternal or perpetuum mobile is possible.

Abstract

We give general arguments that any interacting non--conformal {\it classical} field theory in de Sitter space leads to the possibility of constructing a perpetuum mobile. 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 non-zero even for particles with any finite mass, i.e. with a wavelength which is within the causal domain. Hence, we conclude that either de Sitter space can not exist eternally or that one can build a perpetuum mobile.