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Cosmological constant problem and long-distance modifications of Einstein theory

A. O. Barvinsky
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Abstract

We construct the covariant nonlocal action for recently suggested long-distance modifications of gravity theory motivated by the cosmological constant and cosmological acceleration problems. This construction is based on the special nonlocal form of the Einstein-Hilbert action explicitly revealing the fact that this action within the covariant curvature expansion begins with curvature-squared terms.

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A. O. Barvinsky. 2004-09-14. Cosmological constant problem and long-distance modifications of Einstein theory. https://arxiv.org/abs/hep-th/0409144

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