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arXiv · 1311.3421

Apparent ghosts and spurious degrees of freedom in non-local theories

Stefano Foffa·Michele Maggiore·Ermis Mitsou
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Abstract

Recent work has shown that non-local modifications of the Einstein equations can have interesting cosmological consequences and can provide a dynamical origin for dark energy, consistent with existing data. At first sight these theories are plagued by ghosts. We show that these apparent ghost-like instabilities do not describe actual propagating degrees of freedom, and there is no issue of ghost-induced quantum vacuum decay.

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Stefano Foffa, Michele Maggiore, Ermis Mitsou. 2013-11-15. Apparent ghosts and spurious degrees of freedom in non-local theories. https://doi.org/10.1016/j.physletb.2014.04.024

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