A V Toporensky

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,

The shear dynamics in the Bianchi I cosmological model on the brane

V(\phi) \sim \lambda\phi^4

The nature of singularity in Bianchi I cosmological string gravity model with second order curvature corrections

, is found to agree with observations for values of

Topological entropy for some isotropic cosmological models

\lambda

New properties of scalar-field dynamics in an isotropic cosmological model on the brane

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

Non-singular cosmological models in string gravity with constant dilaton and second-order curvature corrections

V \propto \phi^{-n}

Scaling solutions on a brane

) usually associated with dark energy, can drive inflation in the non-canonical setting. Interestingly, non-canonical scalars violate the consistency relation

Scalar field dynamics on a brane

r = -8n_T

Quantum effects, soft singularities and the fate of the universe in a braneworld cosmology

, which emerges as a {\em smoking gun} test for this class of models.

Aspects of scalar field dynamics in Gauss-Bonnet Brane Worlds

The shear dynamics in Bianchi I cosmological model on the brane with a perfect fluid (the equation of state is