Trace Anomaly Inflation in Brane Induced Gravity

TL;DR

This paper demonstrates that Starobinsky's inflationary solution can be realized within the DGP brane-world model, favoring the conventional branch over the self-accelerated branch, and analyzes the stability of these solutions.

Contribution

It shows the validity of Starobinsky inflation in the DGP model and identifies the conditions under which the conventional branch is preferred over the self-accelerated branch.

Findings

Starobinsky inflation is compatible with the DGP model.

The self-accelerated branch does not support Starobinsky inflation.

Linearized perturbations are stable for certain parameter ranges.

Abstract

In the present letter we find that Starobinsky's inflationary solution is also valid in the Dvali-Gabadadze-Porrati (DGP) model where a 3-brane is embedded in 5-dimensional Minkowski bulk. We show that such a solution is typically not supported by the Self-Accelerated branch of the model, giving therefore a natural selection of the conventional branch of solutions. In the absence of brane induced Einstein-Hilbert term the SA branch is always selected out. We then study the linearized modes around all such de Sitter brane solutions finding perturbative stability for a range of parameters of the brane QFT.