Brane mechanism of spontaneously generated gravity

TL;DR

This paper develops a braneworld model where gravity emerges spontaneously from symmetry breaking, leading to a quadratic gravity action that generalizes the Starobinsky model with a dynamically generated Einstein-Hilbert term.

Contribution

It introduces a brane-based mechanism for spontaneous gravity generation, extending quadratic gravity models with symmetry considerations and a novel origin of the Newton constant.

Findings

Effective 3-brane action invariant under broken scale and Weyl symmetries.

Derivation of a quadratic gravity model generalizing Starobinsky.

Generation of Einstein-Hilbert term with a specific Newton constant.

Abstract

The braneworld scenario is studied and the effective action of 3-brane living in 5-dim. Minkowski space is constructed. This action is proved to be invariant under spontaneously broken scale and Weyl symmetries and to encode a model of quadratic gravity generalizing the Starobinsky model. The symmetry breaking generates the Hilbert-Einstein term with the Newton constant $G_{N}\sim\frac{1}{\mu^{2}}$, where $\mu$ is a mass scale equal to the mean curvature of the vacuum hyper-worldsheet of 3-brane. This result proposes a brane modification of the mechanism of spontaneously generated gravity.