# Relaxation of the Cosmological Constant

## TL;DR

This paper proposes a model where a scalar field dynamically reduces a large positive cosmological constant to a small value, with potential observable effects in cosmology and terrestrial experiments.

## Contribution

It introduces a novel mechanism involving a slowly rolling scalar field to naturally tune the cosmological constant to a small value, linking it to observable phenomena.

## Key findings

- Scalar field can decrease cosmological constant to small negative value
- Model predicts a rolling scalar field today with detectable couplings
- Potential experimental probes include dark energy equation of state and Lorentz violation

## Abstract

We present a model that naturally tunes a large positive cosmological constant to a small cosmological constant. A slowly rolling scalar field decreases the cosmological constant to a small negative value, causing the universe to contract, thus reheating it. An expanding universe with a small positive cosmological constant can be obtained, respectively, by coupling this solution to any model of a cosmological bounce and coupling the scalar field to a sector that undergoes a technically natural phase transition at the meV scale. A robust prediction of this model is a rolling scalar field today with some coupling to the standard model. This can potentially be experimentally probed in a variety of cosmological and terrestrial experiments, such as probes of the equation of state of dark energy, birefringence in the cosmic microwave background and terrestrial tests of Lorentz violation.