Self-Tuning Dark Energy in Brane World Cosmology

TL;DR

This paper proposes a self-tuning mechanism in brane world cosmology where a bulk scalar field adjusts to cancel vacuum energy effects, resulting in a dark energy value consistent with observations despite large vacuum energy.

Contribution

It introduces a novel self-tuning model where a bulk scalar field in brane cosmology dynamically adjusts to neutralize vacuum energy effects.

Findings

The model allows the dark energy to match current observational values.

The bulk scalar field's slowly varying nature is key to the self-tuning process.

The mechanism is robust even with large vacuum energy on the brane.

Abstract

Recently, the self-tuning mechanism of cancellation of vacuum energy has been proposed in which our universe is a flat 3-brane in a 5-dimensional spacetime. In this letter, the self-tuning mechanism of dark energy is proposed by considering the cosmological matter in the brane world. In our model, the bulk scalar field takes the role of the dark energy and its value is slowly varying in time. The claim is that even if the enormous amount of vacuum energy exists on the brane we can adjust the present value of the dark energy to be consistent with the current observations. In this self-tuning mechanism, the existence of the constant of integration associated with the bulk scalar is crucial.