Broken symmetry can yield a positive effective G in conformal gravity

TL;DR

This paper modifies Mannheim's conformal gravity model by altering coefficients to break symmetry, resulting in a cosmology with positive effective G and potential solutions to the cosmological constant problem.

Contribution

It introduces a sign change in the action of conformal gravity, maintaining key benefits while achieving a positive effective G.

Findings

Achieves positive effective G in the modified model

Retains the potential to solve the cosmological constant problem

Demonstrates that breaking conformal symmetry can yield viable cosmological models

Abstract

We modify the action of Mannheim's conformally invariant model by changing the sign of two coefficients. This breaks conformal symmetry, but results in a cosmology that has a positive effective G and at the same time retains one of the main advantages of the Mannheim model, a possible solution of the cosmological constant problem.