Speaker
Description
The non-linear and Lorentz invariant theory of a massive spin--2 field, proposed by de Rham, Gabadadze and Tolley (dRGT), has attracted considerable attention in the last decade, thanks to its potential to provide an alternative to dark energy. However, due to the pathologies of the cosmological solutions, the community has moved on to extensions with additional degrees of freedom and broken symmetries.
In this talk, I will show that the dRGT theory is a special case of a larger class of Lorentz invariant massive spin--2 field theories with 5 degrees of freedom. I will then discuss a minimal example, a proof-of-principle model with: i. none of the pathologies of dRGT cosmology; ii. a late time cosmic acceleration; iii. potentially observable (and distinguishable from scalar-tensor theories) deviations from standard cosmological model at linear order; iv. a new, yet successful, screening mechanism.
