Viable massive gravity without nonlinear screening

TL;DR

This paper investigates nonlinear perturbations in projected massive gravity, revealing that scalar graviton effects vanish and gravitational potentials are suppressed, eliminating the need for a screening mechanism to match solar-system tests.

Contribution

It demonstrates that in projected massive gravity, nonlinear effects do not produce scalar graviton contributions, simplifying the theory's compatibility with local gravity tests.

Findings

Scalar graviton effects vanish at all scales.

Gravitational potential perturbations are strongly suppressed.

No screening mechanism is required for consistency with solar-system experiments.

Abstract

We study nonlinear effects of perturbations around a cosmological background in projected massive gravity, which admits self-accelerating solutions in an open FLRW universe. Using the zero-curvature scaling limit, we derive nonlinear equations containing all the relevant terms on subhorizon scales. We find that the solution for a scalar graviton vanishes completely for all scales, which agrees with the linear perturbation analysis in the previous study. In addition, the effects on the gravitational potential due to the next order perturbation are strongly suppressed within the horizon. Therefore, a screening mechanism is no longer needed for consistency with solar-system experiments in the projected massive gravity.