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arXiv · 0812.3388

Dark Energy and the Return of the Phoenix Universe

Jean-Luc Lehners·Paul J. Steinhardt
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Abstract

In cyclic universe models based on a single scalar field (e.g., the radion determining the distance between branes in M-theory), virtually the entire universe makes it through the ekpyrotic smoothing and flattening phase, bounces, and enters a new epoch of expansion and cooling. This stable evolution cannot occur, however, if scale-invariant curvature perturbations are produced by the entropic mechanism because it requires two scalar fields (e.g., the radion and the Calabi-Yau dilaton) evolving along an unstable classical trajectory. In fact, we show here that an overwhelming fraction of the universe fails to make it through the ekpyrotic phase; nevertheless, a sufficient volume survives and cycling continues forever provided the dark energy phase of the cycle lasts long enough, of order a trillion years. Two consequences are a new role for dark energy and a global structure of the universe radically different from that of eternal inflation.

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Jean-Luc Lehners, Paul J. Steinhardt. 2008-12-17. Dark Energy and the Return of the Phoenix Universe. https://doi.org/10.1103/physrevd.79.063503

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