Towards nonsingular bouncing cosmologies

Yifu Cai

March 08, 2013

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Abstract: A nonsingular bounce suggests that, the Universe starts with a contraction and then reverses to the expansion at a finite size, and thus is well described by general relativity and effective field theory. It is important to examine whether the homogeneous, flat and isotropic background achieved in the contracting phase are maintained through the bounce. I will give a positive example by constructing a single field model to realize a nonsingular bounce which can dilute unwanted anisotropies. The power spectrum can be nearly scale invariant provided the universe has experienced enough long matter dominated contraction.