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arXiv · 1705.03401

A covariant Lagrangian for stable nonsingular bounce

Yong Cai·Yun-Song Piao
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Abstract

The nonsingular bounce models usually suffer from the ghost or gradient instabilities, as has been proved recently. In this paper, we propose a covariant effective theory for stable nonsingular bounce, which has the quadratic order of the second order derivative of the field $\phi$ but the background set only by $P(\phi,X)$. With it, we explicitly construct a fully stable nonsingular bounce model for the ekpyrotic scenario.

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Yong Cai, Yun-Song Piao. 2017-05-09. A covariant Lagrangian for stable nonsingular bounce. https://doi.org/10.1007/jhep09(2017)027

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