Non-singular Cyclic Cosmology without Phantom Menace

Understand

In this article we review recent developments of cyclic cosmology.

• A typical non-singular cyclic model within General Relativity requires a non-conventional fluid with negative effective energy density, in order to cancel the matter component and lead to a non-singular bounce.
• However, the existence of such a non-conventional fluid usually leads to quantum instabilities and makes the theory ill-defined.
• In the present work we follow the alternative way, obtaining two scenarios of non-singular cyclic cosmological evolutions in the context of gravitational theories beyond General Relativity.