The Relaxed Universe: towards solving the cosmological constant problem dynamically from an effective action functional of gravity

Understand

We present an unconventional approach for addressing the old cosmological constant (CC) problem in a class of F(R,G) models of modified gravity.

• For a CC of arbitrary size and sign the corresponding cosmological evolution follows an expansion history which strikingly resembles that of our real universe.
• The effects of the large CC are relaxed dynamically and there is no fine-tuning at any stage.
• In addition, the relaxation mechanism alleviates the coincidence problem.