A Novel Approach to the Cosmological Constant Problem

TL;DR

This paper introduces a new higher-dimensional brane world model that naturally avoids the cosmological constant problem by allowing a non-inflating universe on a spherical brane without fine-tuning, using higher curvature terms.

Contribution

It presents a novel infinite-volume brane world scenario with smooth solutions that keep the brane non-inflating across a range of tensions, eliminating the need for fine-tuning.

Findings

Smooth solutions with non-inflating branes for various tensions

Inclusion of higher curvature terms enables these solutions

Model controlled by a single integration constant

Abstract

We propose a novel infinite-volume brane world scenario where we live on a non-inflating spherical 3-brane, whose radius is somewhat larger than the present Hubble size, embedded in higher dimensional bulk. Once we include higher curvature terms in the bulk, we find completely smooth solutions with the property that the 3-brane world-volume is non-inflating for a continuous range of positive values of the brane tension, that is, without fine-tuning. In particular, our solution, which is a near-BPS background with supersymmetry broken on the brane around TeV, is controlled by a single integration constant.