arXiv subjects
Publications and source records attributed to Ewan D. Stewart.
Recent work is reported on inflation model building in the context of supergravity and superstrings, with special emphasis on False Vacuum (`Hybrid') Chaotic Inflation. Globally supersymmetric models do not survive in generic supergravity theories, but fairly simple conditions can be formulated which do ensure successful supergravity inflation. The conditions are met in some of the versions of supergravity that emerge from superstrings.
A globally supersymmetric model of inflation will not work in a generic supergravity theory because the higher order, nonrenormalisable supergravity corrections destroy the flatness of the inflaton's potential. In this talk I derive a form for the Kahler potential which eliminates these corrections if $ W = \partial W / \partial φ= ψ= 0 $ during inflation (where $W$ is the superpotential, the inflaton is contained in $φ$, and $ \partial W / \partial ψ\neq 0 $). I then point out that Kahler potentials of the required form often occur in superstrings and that the target space duality symmetries of superstrings often contain R-parities which would make $ W = \partial W / \partial φ= 0 $ automatic for $ψ= 0$.
The tunneling rates for scalar fields with quartic potentials in de Sitter space in the limit of no gravitational back reaction are calculated numerically and the results are fitted by analytic formulae.