A semi-classical model of regular inflationary cosmology

Abstract

Quantum-effective gravity must lead to a regularized cosmology and thereby by itself source and regulate the high energy inflaton fields required for an appropriate inflationary beginning of the Universe. Pursuing this premise, we involve in the generic code of extended theories of gravity in conceiving semi-classical imprinting of quantum effects into gravitation. Hence, we prescribe a general semi-classical procedure of constructing the regular, quantum-effective form of the spatially flat FLRW cosmology whereby two alternative classes of the admissible dynamics are distinguished. In this paper, we explore only the particular class holding a minimally inflationary de Sitter UV-phase. Curiously, the low energy phase of the newly modeled Universe recovers the conventional dynamics of loop quantum cosmology. However, unlike the loop quantum cosmology, the high energy phase of the newly conceived cosmology has no bounce, instead, has a regular whimpering emergence of the Universe replacing the Big Bang. Our analysis manifests that without needing any non-standard equation of state, ordinary matter admits an inflationary beginning of the Universe.