https://doi.org/10.1140/epjc/s10052-018-5839-4
Regular Article - Theoretical Physics
A unified universe
1
CP3-Origins, Centre for Cosmology and Particle Physics Phenomenology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
2
Department of Physics, Indian Institute of Science, Bangalore, 560012, India
* e-mail: rkjain@iisc.ac.in
Received:
29
March
2017
Accepted:
24
April
2018
Published online:
3
May
2018
We present a unified evolution of the universe from very early times until the present epoch by including both the leading local correction 
and the leading non-local term 
to the classical gravitational action. We find that the inflationary phase driven by term gracefully exits in a transitory regime characterized by coherent oscillations of the Hubble parameter. The universe then naturally enters into a radiation dominated epoch followed by a matter dominated era. At sufficiently late times after radiation–matter equality, the non-local term starts to dominate inducing an accelerated expansion of the universe at the present epoch. We further exhibit the fact that both the leading local and non-local terms can be obtained within the covariant effective field theory of gravity. This scenario thus provides a unified picture of inflation and dark energy in a single framework by means of a purely gravitational action without the usual need of a scalar field.
© The Author(s), 2018
