Theory HEP Seminar

Self-accelerating universe from non-linear massive gravity

Chunshan Lin

IPMU

In this talk, we simply introduce a recently proposed ghost free non-linear massive gravity theory. By investigating its applications on cosmology, we found open FRW universe solutions which self-accelerate. Given these non-trivial solutions, we study its properties against cosmic perturbation. We found that in the scalar and vector sectors, gauge-invariant variables constructed from metric and matter perturbations have exactly the same quadratic action as in general relativity. The difference from general relativity arises only in the tensor sector, where the graviton mass modifies the dispersion relation of gravitational waves, with a time-dependent effective mass. This may lead to modification of stochastic gravitational wave spectrum.