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Higher Order Slow-Roll Predictions for Inflation

R. Casadio·F. Finelli·M. Luzzi·G. Venturi
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Abstract

We study the WKB approximation beyond leading order for cosmological perturbations during inflation. To first order in the slow-roll parameters, we show that an improved WKB approximation leads to analytical results agreeing to within 0.1% with the standard slow-roll results. Moreover, the leading WKB approximation to second order in the slow-roll parameters leads to analytical predictions in qualitative agreement with those obtained by the Green's function method.

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R. Casadio, F. Finelli, M. Luzzi, G. Venturi. 2005-11-09. Higher Order Slow-Roll Predictions for Inflation. https://doi.org/10.1016/j.physletb.2005.08.056

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