Relaxing the Cosmological Constant, Proof of Concept
Abstract: We propose a technically natural and phenomenological viable scenario whereby an initially large cosmological constant (c.c.) is relaxed down to the observed value due to the dynamics of a scalar evolving on a very shallow potential. The model crucially relies on a sector that violates the null energy condition (NEC) and gets activated only when the Hubble rate becomes sufficiently small — of the order of the present one. As a result of NEC violation, this low-energy universe evolves into inflation, followed by reheating and the standard Big Bang cosmology. Importantly, our model allows neither for eternal inflation and the current value of the c.c. is fixed by the parameters of the theory.
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