Cosmological Consequences of a Variable Cosmological Constant Model

Abstract

We derive a model of dark energy which evolves with time via the scale factor. The equation of state $\omega =(1-2\alpha )/(1+2\alpha )$ is studied as a function of a parameter $\alpha$ introduced in this model. In addition to the recent accelerated expansion, the model predicts another decelerated phase. The age of the universe is found to be almost consistent with observation. In the limiting case, the cosmological constant model, we find that vacuum energy gravitates with a gravitational strength, different than Newton's constant. This enables degravitation of the vacuum energy which in turn produces the tiny observed curvature, rather than a 120 orders of magnitude larger value.

Accepted in Int. J. Mod. Phys. D

References in corpus (3)

• Planck 2013 results. XVI. Cosmological parameters
• Riemann-Eddington theory: Incorporating matter, degravitating the cosmological constant
• Eddington's Gravity in Immersed Spacetime

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