Refining inflation using non-canonical scalars
  This paper revisits the Inflationary scenario within the framework of scalar
field models possessing a non-canonical kinetic term. We obtain closed form
solutions for all essential quantities associated with chaotic inflation
including slow roll parameters, scalar and tensor power spectra, spectral
indices, the tensor-to-scalar ratio, etc. We also examine the Hamilton-Jacobi
equation and demonstrate the existence of an inflationary attractor. Our
results highlight the fact that non-canonical scalars can significantly improve
the viability of inflationary models. They accomplish this by decreasing the
tensor-to-scalar ratio while simultaneously increasing the value of the scalar
spectral index, thereby redeeming models which are incompatible with the cosmic
microwave background (CMB) in their canonical version. For instance, the
non-canonical version of the chaotic inflationary potential, $V(\phi) \sim
\lambda\phi^4$, is found to agree with observations for values of $\lambda$ as
large as unity ! The exponential potential can also provide a reasonable fit to
CMB observations. A central result of this paper is that {\em steep potentials}
(such as $V \propto \phi^{-n}$) usually associated with dark energy, can drive
inflation in the non-canonical setting. Interestingly, non-canonical scalars
violate the consistency relation $r = -8n_T$, which emerges as a {\em smoking
gun} test for this class of models.
