Slow roll in simple non-canonical inflation
Abstract
We consider inflation using a class of non-canonical Lagrangians for which the modification to the kinetic term depends on the field, but not its derivatives. We generalize the standard Hubble slow roll expansion to the non-canonical case and derive expressions for observables in terms of the generalized slow roll parameters. We apply the general results to the illustrative case of ``Slinky'' inflation, which has a simple, exactly solvable, non-canonical representation. However, when transformed into a canonical basis, Slinky inflation consists of a field oscillating on a multi-valued potential. We calculate the power spectrum of curvature perturbations for Slinky inflation directly in the non-canonical basis, and show that the spectrum is approximately a power law on large scales, with a ``blue'' power spectrum. On small scales, the power spectrum exhibits strong oscillatory behavior. This is an example of a model in which the widely used solution of Garriga and Mukhanov gives the wrong answer for the power spectrum.
Keywords
Cite
@article{arxiv.astro-ph/0701343,
title = {Slow roll in simple non-canonical inflation},
author = {Gabriela Barenboim and William H. Kinney},
journal= {arXiv preprint arXiv:astro-ph/0701343},
year = {2010}
}
Comments
9 pages, LaTeX, four figures. (V2: minor changes to text. Version submitted to JCAP.)