Running of Newton's constant and non integer powers of the d'Alembertian

LOPEZ NACIR, DIANA; MAZZITELLI, F.D.

PHYSICAL REVIEW D - PARTICLE AND FILDS

APS

Lugar: New York; Año: 2006

0556-2821

The running of Newton´s constant can be taken into account by considering covariant, non local generalizations of the field equations of general relativity. These generalizations involve nonanalytic functions of the d´Alembertian, as $(-Box)^{-alpha}$, with $alpha$ a non integer number, and $ln[-Box]$. In this paper we define these non local operators in terms of the usual two point function of a massive field. We analyze some of their properties, and present specific calculations in flat and Robertson Walker spacetimes.