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arXiv · 0709.1124

The Adiabatic Instability on Cosmology's Dark Side

Rachel Bean·Eanna E. Flanagan·Mark Trodden
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Abstract

We consider theories with a nontrivial coupling between the matter and dark energy sectors. We describe a small scale instability that can occur in such models when the coupling is strong compared to gravity, generalizing and correcting earlier treatments. The instability is characterized by a negative sound speed squared of an effective coupled dark matter/dark energy fluid. Our results are general, and applicable to a wide class of coupled models and provide a powerful, redshift-dependent tool, complementary to other constraints, with which to rule many of them out. A detailed analysis and applications to a range of models are presented in a longer companion paper.

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Rachel Bean, Eanna E. Flanagan, Mark Trodden. 2007-09-07. The Adiabatic Instability on Cosmology's Dark Side. https://doi.org/10.1088/1367-2630%2F10%2F3%2F033006

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