Eur. Phys. J. C (2014) 74: 2999
https://doi.org/10.1140/epjc/s10052-014-2999-8

Regular Article - Theoretical Physics

Super-accelerating bouncing cosmology in asymptotically free non-local gravity

¹ Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006, Madrid, Spain
² Department of Physics and Center for Field Theory and Particle Physics, Fudan University, Shanghai, 200433, China
³ Frankfurt Institute for Advanced Studies (FIAS) and Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, 60438, Frankfurt am Main, Germany

^* e-mail: calcagni@iem.cfmac.csic.es

Received: 12 April 2014
Accepted: 25 July 2014
Published online: 21 August 2014

Abstract

Recently, evidence has been collected that a class of gravitational theories with certain non-local operators is renormalizable. We consider one such model which, at the linear perturbative level, reproduces the effective non-local action for the light modes of bosonic closed string-field theory. Using the property of asymptotic freedom in the ultraviolet and fixing the classical behavior of the scale factor at late times, an algorithm is proposed to find general homogeneous cosmological solutions valid both at early and late times. Imposing a power-law classical limit, these solutions (including anisotropic ones) display a bounce, instead of a big-bang singularity, and super-accelerate near the bounce even in the absence of an inflaton or phantom field.