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arXiv · 1109.1308

Cosmological perturbations in $k$-essence model

Kazuharu Bamba·Jiro Matsumoto·Shin'ichi Nojiri
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Abstract

Subhorizon approximation is often used in cosmological perturbation theory. In this paper, however, it is shown that the subhorizon approximation is not always a good approximation at least in case of $k$-essence model. We also show that the sound speed given by $k$-essence model exerts a huge influence on the time evolution of the matter density perturbation, and the future observations could clarify the differences between the $Λ$CDM model and $k$-essence model.

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Kazuharu Bamba, Jiro Matsumoto, Shin'ichi Nojiri. 2012-03-16. Cosmological perturbations in $k$-essence model. https://doi.org/10.1103/physrevd.85.084026

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