Accelerating universe in modified theories of gravity

Journal Article · Wed Apr 15 04:00:00 EDT 2009 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.79.083534· OSTI ID:21308291

Paul, B C; Debnath, P S; Ghose, S ^[1]

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1. Physics Department, North Bengal University, Siliguri, District Darjeeling, Pin-734 013 (India)

We study cosmologies in modified theories of gravity considering Lagrangian density f(R) which is a polynomial function of scalar curvature (R) in the Einstein-Hilbert action in vacuum. The field equation obtained from the modified action corresponding to a Robertson-Walker metric is highly nonlinear and not simple enough to obtain analytic solution. Consequently we adopt a numerical technique to study the evolution of the Friedmann-Robertson-Walker universe. A number of evolutionary phases of the Universe including the present accelerating phase are found to exist in the higher derivative theories of gravity. The cosmological solutions obtained here are new and interesting. We study a modified theory of gravity as a toy model to explore the past and the present, and to predict the future evolution. It is found that all the models analyzed here can reproduce the current accelerating phase of expansion of the Universe. The duration of the present accelerating phase is found to depend on the coupling constants of the gravitational action. The physical importance of the coupling parameters considered in the action are also discussed.

• OSTI ID: 21308291
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 8 Vol. 79; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANALYTICAL SOLUTION
COSMOLOGY
COUPLING
COUPLING CONSTANTS
DENSITY
EXPANSION
FIELD EQUATIONS
GRAVITATION
LAGRANGIAN FUNCTION
METRICS
NONLINEAR PROBLEMS
POLYNOMIALS
UNIVERSE