The solution of the cosmological constant problem from the inhomogeneous equation of state - a hint from modified gravity?

Abstract

The cosmological constant problem is studied in a two component cosmological model. The universe contains a cosmological constant of an arbitrary size and sign and an additional component with an inhomogeneous equation of state. It is shown that, in a proper parameter regime, the expansion of the universe with a large absolute value of the cosmological constant may asymptotically tend to de Sitter space corresponding to a small effective positive cosmological constant. It is argued that such a behavior can be regarded as a solution of the cosmological constant problem in this model. The mechanism behind the relaxation of the cosmological constant is discussed. A connection with modified gravity theories is discussed and an example of a possible realization of the cosmological constant relaxation in f(R) modified gravity is described.

18 pages, 8 figures, version to appear in Phys. Lett. B

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Cited by in corpus (4)

• Initial and final de Sitter universes from modified $f(R)$ gravity
• Relaxing a large cosmological constant
• The inhomogeneous equation of state and the road towards the solution of the cosmological constant problem
• The inhomogeneous equation of state and the speed of convergence to a small cosmological constant