Interacting dark energy in f(R) gravity

Journal Article · Sun Oct 15 04:00:00 EDT 2006 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.74.084032· OSTI ID:20871424

Poplawski, Nikodem J ^[1]

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1. Department of Physics, Indiana University, 727 East Third Street, Bloomington, Indiana 47405 (United States)

The field equations in f(R) gravity derived from the Palatini variational principle and formulated in the Einstein conformal frame yield a cosmological term which varies with time. Moreover, they break the conservation of the energy-momentum tensor for matter, generating the interaction between matter and dark energy. Unlike phenomenological models of interacting dark energy, f(R) gravity derives such an interaction from a covariant Lagrangian which is a function of a relativistically invariant quantity (the curvature scalar R). We derive the expressions for the quantities describing this interaction in terms of an arbitrary function f(R), and examine how the simplest phenomenological models of a variable cosmological constant are related to f(R) gravity. Particularly, we show that {lambda}c{sup 2}=H{sup 2}(1-2q) for a flat, homogeneous and isotropic, pressureless universe. For the Lagrangian of form R-1/R, which is the simplest way of introducing current cosmic acceleration in f(R) gravity, the predicted matter-dark energy interaction rate changes significantly in time, and its current value is relatively weak (on the order of 1% of H{sub 0}), in agreement with astronomical observations.

• OSTI ID: 20871424
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 8 Vol. 74; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ACCELERATION
BASIC INTERACTIONS
COSMOLOGICAL CONSTANT
COSMOLOGY
ENERGY-MOMENTUM TENSOR
FIELD EQUATIONS
GRAVITATION
LAGRANGIAN FUNCTION
NONLUMINOUS MATTER
SCALARS
UNIVERSE
VARIATIONAL METHODS