Lorentz violation and perpetual motion
Abstract
We show that any Lorentzviolating theory with two or more propagation speeds is in conflict with the generalized second law of black hole thermodynamics. We do this by identifying a classical energyextraction method, analogous to the Penrose process, which would decrease the black hole entropy. Although the usual definitions of black hole entropy are ambiguous in this context, we require only very mild assumptions about its dependence on the mass. This extends the result found by Dubovsky and Sibiryakov, which uses the Hawking effect and applies only if the fields with different propagation speeds interact just through gravity. We also point out instabilities that could interfere with their black hole perpetuum mobile, but argue that these can be neglected if the black hole mass is sufficiently large.
 Publication:

Physical Review D
 Pub Date:
 May 2007
 DOI:
 10.1103/PhysRevD.75.101502
 arXiv:
 arXiv:hepth/0702124
 Bibcode:
 2007PhRvD..75j1502E
 Keywords:

 04.70.Dy;
 04.20.Cv;
 Quantum aspects of black holes evaporation thermodynamics;
 Fundamental problems and general formalism;
 High Energy Physics  Theory;
 General Relativity and Quantum Cosmology
 EPrint:
 5 pages, 1 figure