Large Slow Roll Parameters in Single Field Inflation

Abstract

We initially consider two simple situations where inflationary slow roll parameters are large and modes no longer freeze out shortly after exiting the horizon, treating both cases analytically. We then consider applications to transient phases where the slow roll parameters can become large, especially in the context of the common `fast-roll' inflation frequently used as a mechanism to explain the anomalously low scalar power at low $l$ in the CMB. These transient cases we treat numerically. We find when $\epsilon$, the first slow roll parameter, and only $\epsilon$ is large, modes decay outside the horizon, and when $\delta$, the second slow roll parameter, is large, modes grow outside the horizon. When multiple slow roll parameters are large the behavior in general is more complicated, but we nevertheless show in the 'fast-roll' inflation case, modes grow outside the horizon.

21 pages, 11 figures

References in corpus (11)

• Wiggly Whipped Inflation
• Whipped inflation
• Just enough inflation: power spectrum modifications at large scales
• Consistently violating the non-Gaussian consistency relation
• Inflation over the hill
• CMB quadrupole suppression: II. The early fast roll stage
• Suppressing the impact of a high tensor-to-scalar ratio on the temperature anisotropies
• On the evolution of tachyonic perturbations at super-Hubble scales
• The large scale CMB cut-off and the tensor-to-scalar ratio
• Inflation After False Vacuum Decay: New Evidence from BICEP2
• Scalar suppression on large scales in open inflation

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