On gravitational waves in Born-Infeld inspired non-singular cosmologies

Understand

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.