A note on the cosmological constant in f(R) gravity

Abstract

The starting point in this note is $f(R)$ modified gravity in a cosmological setting. We assume a spatially flat Universe to describe late-time cosmology and the perfect-fluid equation of state $p=\omega \rho$ to model the hypothesized dark energy. Given that on a cosmological scale, $f(R)$ modified gravity must remain close to Einstein gravity to be consistent with observation, it was concluded that either (1) Einstein's cosmological constant is the only acceptable model for the accelerated expansion or (2) that the equation of state for dark energy is far more complicated than the perfect-fluid model and may even exclude a constant $\omega$.

arXiv comment7 pages, 1 figure

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• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• f(R) Theories Of Gravity
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Cited by in corpus (1)

• A model for dark energy based on the theory of embedding