PT Journal
AU Beltran Jimenez, J
   Heisenberg, L
   Olmo, GJ
   Rubiera-Garcia, D
TI On gravitational waves in Born-Infeld inspired non-singular cosmologies
SO Journal of Cosmology and Astroparticle Physics
JI J. Cosmol. Astropart. Phys.
PY 2017
BP 029
EP 23pp
VL 10
IS 10
DI 10.1088/1475-7516/2017/10/029
LA English
DE alternatives to inflation; modified gravity; physics of the early universe; primordial gravitational waves (theory)
AB We study the evolution of gravitational waves for non-singular cosmological solutions within the framework of Born-Infeld inspired gravity theories, with special emphasis on the Eddington-inspired Born-Infeld theory. We review the existence of two types of non-singular cosmologies, namely bouncing and asymptotically Minkowski solutions, from a perspective that makes their features more apparent. We study in detail the propagation of gravitational waves near these non-singular solutions and carefully discuss the origin and severity of the instabilities and strong coupling problems that appear. We also investigate the role of the adiabatic sound speed of the matter sector in the regularisation of the gravitational waves evolution. We extend our analysis to more general Born-Infeld inspired theories where analogous solutions are found. As a general conclusion, we obtain that the bouncing solutions are generally more prone to instabilities, while the asymptotically Minkowski solutions can be rendered stable, making them appealing models for the early universe.
ER