A General Supergravity Formalism for a Naturally Flat Inflaton Potential

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 $W = \partial W / \partial \varphi = \psi = 0$ during inflation (where $W$ is the superpotential, the inflaton is contained in $\varphi$, and $\partial W / \partial \psi \neq 0$). 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 $W = \partial W / \partial \varphi = 0$ automatic for $\psi = 0$.