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Non-linear inflationary perturbations

G. I. Rigopoulos·E. P. S. Shellard
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Abstract

We present a method by which cosmological perturbations can be quantitatively studied in single and multi-field inflationary models beyond linear perturbation theory. A non-linear generalization of the gauge-invariant Sasaki-Mukhanov variables is used in a long-wavelength approximation. These generalized variables remain invariant under time slicing changes on long wavelengths. The equations they obey are relatively simple and can be formulated for a number of time slicing choices. Initial conditions are set after horizon crossing and the subsequent evolution is fully non-linear. We briefly discuss how these methods can be implemented numerically in the study of non-Gaussian signatures from specific inflationary models.

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G. I. Rigopoulos, E. P. S. Shellard. 2005-10-19. Non-linear inflationary perturbations. https://doi.org/10.1088/1475-7516%2F2005%2F10%2F006

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