Bounce and cyclic cosmology in extended nonlinear massive gravity
  We investigate non-singular bounce and cyclic cosmological evolutions in a universe governed by the extended nonlinear massive gravity, in which the graviton mass is promoted to a scalar-field potential. The extra freedom of the theory can lead to certain energy conditions violations and drive cyclicity with two different mechanisms: either with a suitably chosen scalar-field potential under a given Stuckelberg-scalar function, or with a suitably chosen Stuckelberg-scalar function under a given scalar-field potential. Our analysis shows that extended nonlinear massive gravity can alter significantly the evolution of the universe at both early and late times. 
Yi-Fu Cai (Arizona State U. and McGill U.), Caixia Gao (Mississippi   U.), Emmanuel N. Saridakis (Natl. Tech. U., Athens and...
astro-ph.CO gr-qc hep-th