New counterterms induced by trans-Planckian physics in semiclassical gravity

LOPEZ NACIR, DIANA; F.D. MAZZITELLI

PHYSICAL REVIEW D - PARTICLE AND FILDS

APS

Lugar: New York; Año: 2008 vol. 78 p. 44001 - 44008

0556-2821

We consider free and self-interacting quantum scalar fields satisfying modified dispersion relations in the framework of Einstein-Aether theory. Using adiabatic regularization, we study the renormalization of the equation for the mean value of the field in the self-interacting case, and the renormalization of the semiclassical Einstein-Aether equations for free fields. In both cases we consider Bianchi type I background spacetimes. Contrary to what happens for {it free} fields in {it flat} Robertson-Walker spacetimes, the self-interaction and/or the anisotropy produce non-purely geometric terms in the adiabatic expansion, i.e terms that involve both the metric $g_{muu}$ and the aether field $u_{mu}$. We argue that, in a general spacetime, the renormalization of the theory would involve new counterterms constructed with $g_{muu}$ and $u_{mu}$, generating a fine-tuning problem for the Einstein-Aether theory.