dRGT ghost-free massive gravity in spherical symmetry

          @misc{ pirsa_PIRSA:24110075,
            doi = {10.48660/24110075},
            url = {https://pirsa.org/24110075},
            author = {},
            keywords = {Cosmology},
            language = {en},
            title = {dRGT ghost-free massive gravity in spherical symmetry},
            publisher = {Perimeter Institute},
            year = {2024},
            month = {nov},
            note = {PIRSA:24110075 see, \url{https://pirsa.org}}
          }
          

Abstract

In my talk, I will argue that symmetry strongly changes the behaviour of massive gravity relative to its massless sibling.   After reviewing the formulation of dRGT theory of ghost-free massive gravity, I will examine the minimal model and next-to-minimal model in spherical symmetry. Although the latter has been argued to have a good Vainshtein mechanism in spherical symmetry, I will derive a restriction on non-relativistic matter that is at odds with a reasonable phenomenology. Moreover, the theory cannot reproduce the same behaviour as GR for a scalar field collapse in the small mass limit without encountering a singularity at some point in the evolution.   Since symmetry is the epitome of non-genericity, the resolution may well be that we should forgo symmetry and focus on more generic behaviour in massive gravity to study the screening mechanism. This talk is based on https://arxiv.org/pdf/2409.18802