Chaotic inflation in modified gravitational theories
Elliston, Joseph (Queen Mary, University of London)

We study chaotic inflation in the context of modified gravitational theories and apply up-to-date constraints from WMAP 7yr combined with other observations. Our analysis covers models based on (i) a field coupling to the kinetic energy and nonmimimal coupling with the Ricci scalar R, (ii) Brans-Dicke (BD) theories, (iii) Gauss-Bonnet (GB) gravity, and (iv) gravity with a Galileon correction. We investigate the effects of these terms on the scalar and tensor spectral indices as well as the tensor to scalar ratio. The self-coupling inflationary potential, ruled out by current observations, is shown to be compatible with data in a variety of such generalised settings. The ability for such theories to generate large non-Gaussianitites is also discussed.