Weak gravity in DGP braneworld model

TL;DR

This paper investigates how gravity behaves at weak scales in the DGP braneworld model, addressing limitations of previous linear perturbation methods and extending the analysis to more general perturbations and model variants.

Contribution

It develops an alternative formulation for analyzing weak gravity in the DGP model beyond spherical symmetry and generalizes the model by including bulk cosmological constant and brane tension.

Findings

Clarified the recovery mechanism of 4D GR in the DGP model.

Derived leading corrections to 4D GR beyond spherical symmetry.

Extended the model to include bulk cosmological constant and brane tension.

Abstract

We analyze the weak gravity in the braneworld model proposed by Dvali-Gabadadze-Porrati, in which the unperturbed background spacetime is given by five dimensional Minkowski bulk with a brane which has the induced Einstein Hilbert term. This model has a critical length scale $r_c$. Naively, we expect that the four dimensional general relativity (4D GR) is approximately recovered at the scale below $r_c$. However, the simple linear perturbation does not work in this regime. Only recently the mechanism to recover 4D GR was clarified under the restriction to spherically symmetric configurations, and the leading correction to 4D GR was derived. Here, we develop an alternative formulation which can handle more general perturbations. We also generalize the model by adding bulk cosmological constant and the brane tension.