Eur. Phys. J. C (2015) 75: 444
https://doi.org/10.1140/epjc/s10052-015-3672-6

Regular Article - Theoretical Physics

Inflation in -theories and mimetic gravity scenario

¹ Department of General and Theoretical Physics and Eurasian Center for Theoretical Physics, Eurasian National University, Astana, 010008, Kazakhstan
² Niels Bohr International Academy and Discovery Center, Niels Bohr Institute, University of Copenhagen, Blegdamsvej 17, 2100, Copenhagen Ø, Denmark
³ Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, 106 91, Stockholm, Sweden
⁴ Department of Physics, The Oskar Klein Centre for Cosmoparticle Physics, Stockholm University, AlbaNova, 106 91, Stockholm, Sweden
⁵ ARC Centre of Excellence for Particle Physics at the Terascale, School of Physics, University of Melbourne, Melbourne, VIC, 3010, Australia

^* e-mail: l.sebastiani@science.unitn.it

Received: 16 June 2015
Accepted: 8 September 2015
Published online: 23 September 2015

Abstract

We investigate inflation within -theories, where a dynamical scalar field is coupled to gravity. A class of models which can support early-time acceleration with the emerging of an effective cosmological constant at high curvature is studied. The dynamics of the field allow for exit from inflation leading to the correct amount of inflation in agreement with cosmological data. Furthermore, the spectral index and tensor-to-scalar ratio of the models are carefully analyzed. A generalization of the theory to incorporate dark matter in the context of mimetic gravity, and further extensions of the latter, are also discussed.