Gianluca Calcagni, Leonardo Modesto, Piero Nicolini
Recently, evidence has been collected that a class of gravitational theories with certain non-local operators is renormalizable. We consider one such model which, at the linear perturbative level, reproduces the effective non-local action for the light modes of bosonic closed string field theory. Using the property of asymptotic freedom in the ultraviolet and fixing the classical behaviour of the scale factor at late times, an algorithm is proposed to find general homogeneous cosmological solutions valid both at early and late times. Imposing a power-law classical limit, these solutions (including anisotropic ones) display a bounce instead of a big-bang singularity, and super-accelerate near the bounce even in the absence of an inflaton or phantom field.
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http://arxiv.org/abs/1306.5332
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