Vainshtein mechanism in Generalised Massive Gravity

We present a non-linear analysis of perturbations around cosmological solutions in Generalised Massive gravity. This Lorentz invariant theory is an extension of de Rham, Gabadadze, Tolley massive gravity that propagates 5 degrees of freedom while allowing stable open FLRW cosmologies. For a minimal model that supports a self-accelerating background, we study the dynamics of non-linear perturbations. We find that the equation for the scalar graviton is distinct from the analogues in Horndeski and DHOST theories. We numerically solve the equation to find a new type of nonlinear solution for the scalar mode, and confirm the presence of a Vainshtein screening mechanism. We show that the PPN parameter approaches its GR value at solar system scales and satisfies the current bounds.

Automated summary

In Generalised Massive gravity, a non-linear analysis of perturbations around cosmological solutions was conducted, leading to the discovery of a new type of non-linear solution for the scalar mode and confirmation of the presence of the Vainshtein screening mechanism. The PPN parameter approaches its GR value at solar system scales and meets current constraints.