Theory Seminar

KEK 素粒子原子核研究所・理論セミナー



TITLE f(R) models for the early and the present acceleration of the Universe
(Up to audience; in English or in Japanese)
SPEAKER Hayato Motohashi
(RESCEU, University of Tokyo)
DATE: Mar 13 (Tue.) 11:00 − 12:00
PLACE: Kenkyuhonkan, 1F, Meeting Room 1



    ABSTRACT

f(R) gravity is a simple and nontrivial extension of General Relativity. The idea was originally proposed in 1980 by Starobinsky, and now it is recognized as R^2 inflationary model. Several years ago, it was also applied to describe dark energy in the present Universe. Although some of f(R) models can satisfy laboratory, Solar system and cosmological tests, it was found that there are weak singularities and other problems in this class of models. Recently, it is found that we are able to cure the problem and describe both accelerating expansion in the early and the present Universe. I will talk about this class of f(R) models and the dynamics during inflation and reheating.