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Cosmological Bounce and Some Other Solutions in Exponential Gravity

Authors :
Pritha Bari
Kaushik Bhattacharya
Saikat Chakraborty
Source :
Universe, Vol 4, Iss 10, p 105 (2018)
Publication Year :
2018
Publisher :
MDPI AG, 2018.

Abstract

In this work, we present some cosmologically relevant solutions using the spatially flat Friedmann-Lemaitre-Robertson-Walker (FLRW) spacetime in metric f ( R ) gravity where the form of the gravitational Lagrangian is given by 1 α e α R . In the low curvature limit this theory reduces to ordinary Einstein-Hilbert Lagrangian together with a cosmological constant term. Precisely because of this cosmological constant term this theory of gravity is able to support nonsingular bouncing solutions in both matter and vacuum background. Since for this theory of gravity f ′ and f ″ is always positive, this is free of both ghost instability and tachyonic instability. Moreover, because of the existence of the cosmological constant term, this gravity theory also admits a de-Sitter solution. Lastly we hint towards the possibility of a new type of cosmological solution that is possible only in higher derivative theories of gravity like this one.

Details

Language :
English
ISSN :
22181997
Volume :
4
Issue :
10
Database :
Directory of Open Access Journals
Journal :
Universe
Publication Type :
Academic Journal
Accession number :
edsdoj.87ea84e4f2ec4d6c877e4567f1e3060a
Document Type :
article
Full Text :
https://doi.org/10.3390/universe4100105