Superspace dependence of the Vilkovisky-DeWitt effective action for quantum gravity.

Abstract

The definition of the Vilkovisky-DeWitt effective action for gravity theories permits the introduction of a metric in the field space that depends on a parameter \ensuremath{\lambda}. We study the consequences in the quantum theory of keeping this parameter free in ordinary and in higher derivative gravity. We do this by computing the renormalization group equations for an arbitrary \ensuremath{\lambda}. In both cases we see that it is possible to have a decay mechanism for the cosmological constant while maintaining a phenomenologically interesting behavior for Newton's constant.