Open Access Publications from the University of California

## Supersymmetry, Inflation, and Dark Matter

In this thesis, we study supersymmetry in various contexts. We begin with a study of perturbation theory of supersymmetric quantum electrodynamics. We note that computing the one-particle-irreducible effective action using a general $R_\xi$ gauge gives rise to infrared divergences, whose cancellation from physical quantities such as the electron pole mass occurs somewhat subtly. We discuss nonrenormalization theorems, both perturbative and non-perturbative.
Following that, we discuss models of inflationary cosmology, in which we employ supersymmetry as a tool for achieving nearly flat inflaton potentials. We systematically consider Planck-scale corrections to models of hybrid inflation, i.e. models in which inflation takes place on a pseudo-moduli space. We investigate the extent to which these models must be tuned to accommodate the 2013 Planck Satellite result for the spectral index, $n_s = 0.96$.