TITLE:
A Note on the Cosmological Constant in f(R) Gravity
AUTHORS:
Peter K. F. Kuhfittig
KEYWORDS:
Cosmological Constant, f(R) Gravity
JOURNAL NAME:
Journal of Applied Mathematics and Physics,
Vol.5 No.4,
April
30,
2017
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 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 was the only acceptable model for the accelerated expansion, or that (2) the equation of state for dark energy was far more complicated than the perfect-fluid model and might even exclude a constant w.