Induced cosmological constant and other features of asymmetric brane embedding

TL;DR

This paper explores how asymmetric brane embeddings in cosmology can lead to diverse universe evolution scenarios, including self-acceleration and phantom acceleration, and offers a novel mechanism for inducing a small positive cosmological constant.

Contribution

It demonstrates that removing mirror symmetry in brane models results in four evolution branches and provides a new way to generate a small positive cosmological constant through asymmetry.

Findings

Four distinct brane evolution branches identified.

Asymmetry induces a small positive cosmological constant.

Model includes phantom acceleration and cosmic mimicry.

Abstract

We investigate the cosmological properties of an "induced gravity" brane scenario in the absence of mirror symmetry with respect to the brane. We find that brane evolution can proceed along one of four distinct branches. By contrast, when mirror symmetry is imposed, only two branches exist, one of which represents the self-accelerating brane, while the other is the so-called normal branch. This model incorporates many of the well-known possibilities of brane cosmology including phantom acceleration (w < -1), self-acceleration, transient acceleration, quiescent singularities, and cosmic mimicry. Significantly, the absence of mirror symmetry also provides an interesting way of inducing a sufficiently small cosmological constant on the brane. A small (positive) Lambda-term in this case is induced by a small asymmetry in the values of bulk fundamental constants on the two sides of the brane.