A Brane World Solution to the Cosmological Constant Problem

TL;DR

This paper proposes a brane world model in 5-dimensional spacetime where the effective 4D cosmological constant becomes exponentially small with increasing interbrane separation, offering a potential solution to the cosmological constant problem.

Contribution

It introduces a two-brane model with specific geometric conditions that naturally suppress the cosmological constant without fine-tuning.

Findings

Effective 4D cosmological constant decreases exponentially with brane separation.

Anti-deSitter geometry or absence of horizons is crucial for the suppression.

Model provides a geometric mechanism for addressing the cosmological constant problem.

Abstract

We consider a model with two parallel (positive tension) 3-branes separated by a distance $L$ in 5-dimensional spacetime. If the interbrane space is anti-deSitter, or is not precisely anti-deSitter but contains no event horizons, the effective 4-dimensional cosmological constant seen by observers on one of the branes (chosen to be the visible brane) becomes exponentially small as $L$ grows large.