Non-singular Cyclic Cosmology without Phantom Menace
  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. The
degrees-of-freedom examination reveals that these two models are free of the
Phantom Menace. Our analysis illustrates that, if cyclic cosmology describes
overall universe, a theory of gravity beyond Einstein may be expected.
