Sanil Unnikrishnan, Varun Sahni
It is well known that a canonical scalar field with an exponential potential can drive power law inflation (PLI). However, the tensor-to-scalar ratio in such models turns out to be larger than the stringent limit set by recent \emph{Planck} results. Power law inflation can also be realized in a k-inflation model such as the one proposed by Armendariz-Picon {\it et. al.}\cite{Picon-1999}. Although, the scalar spectral index and the tensor-to-scalar ratio for this model are within \emph{Planck} limits, it is difficult to reconcile the large value of the non-gaussianity parameter $f_{_{\mathbf{NL}}}^{\mathrm{equil}}$ in this model with the bounds set by the \emph{Planck} data. We propose a new model of power law inflation for which the scalar spectra index, the tensor-to-scalar ratio and the non-gaussianity parameter $f_{_{\mathbf{NL}}}^{\mathrm{equil}}$ are in excellent agreement with \emph{Planck} results. Inflation, in this model, is driven by a non-canonical scalar field with an {\em inverse power law} potential. The Lagrangian for our model is structurally similar to that of a canonical scalar field and has a power law form for the kinetic term. A simple extension of our model resolves the graceful exit problem which usually afflicts models of power law inflation.
View original:
http://arxiv.org/abs/1305.5260
No comments:
Post a Comment