PIRSA:12100002

Homogeneous and Isotropic Universe from Nonlinear Massive Gravity

Gumrukcuoglu, A.E. (2012). Homogeneous and Isotropic Universe from Nonlinear Massive Gravity. Perimeter Institute. https://pirsa.org/12100002

Gumrukcuoglu, A. Emir. Homogeneous and Isotropic Universe from Nonlinear Massive Gravity. Perimeter Institute, Oct. 02, 2012, https://pirsa.org/12100002 

          @misc{ pirsa_PIRSA:12100002,
            doi = {10.48660/12100002},
            url = {https://pirsa.org/12100002},
            author = {Gumrukcuoglu, A. Emir},
            keywords = {Cosmology},
            language = {en},
            title = {Homogeneous and Isotropic Universe from Nonlinear Massive Gravity},
            publisher = {Perimeter Institute},
            year = {2012},
            month = {oct},
            note = {PIRSA:12100002 see, \url{https://pirsa.org}}
          }

A. Emir Gumrukcuoglu

Talk numberPIRSA:12100002
DOI10.48660/12100002
Collection
Talk Type Scientific Series
Subject

Abstract

The question of finite range gravity, or equivalently, whether graviton can have a non-zero mass, has been one of the major challenges in classical field theory for the last 70 years. Generically, a massive gravity theory contains an extra degree in addition to the 5 polarizations of massive graviton, which turns out to be a ghost. Recently, de Rham, Gabadadze and Tolley constructed a nonlinear theory of massive gravity, which successfully eliminates the ghost. Moreover, the theory has also phenomenological relevance, since the graviton mass may account for the accelerated expansion of the present universe, providing an alternative to dark energy. I will present self-accelerating cosmological solutions in the framework of this theory. The cosmological perturbations around these backgrounds have an interesting behavior: instead of the 5 degrees of freedom expected from a massive spin-2 field, only the 2 gravity wave polarizations are dynamical, at linear level. However, nonlinear analysis of the extra modes reveal the existence of ghost instabilities. This implies that a consistent universe solution in this theory should be inhomogeneous and/or anisotropic.