A general proof of the conservation of the curvature perturbation

David H. Lyth; Karim A. Malik; Misao Sasaki

doi:10.1088/1475-7516/2005/05/004

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A general proof of the conservation of the curvature perturbation

David H. Lyth·Karim A. Malik·Misao Sasaki

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Abstract

Without invoking a perturbative expansion, we define the cosmological curvature perturbation, and consider its behaviour assuming that the universe is smooth over a sufficiently large comoving scale. The equations are simple, resembling closely the first-order equations, and they lead to results which generalise those already proven in linear perturbation theory and (in part) in second-order perturbation theory. In particular, the curvature perturbation is conserved provided that the pressure is a unique function of the energy density.

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David H. Lyth, Karim A. Malik, Misao Sasaki. 2005-05-30. A general proof of the conservation of the curvature perturbation. https://doi.org/10.1088/1475-7516%2F2005%2F05%2F004

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