The inflationary energy scale

The energy scale of inflation is of much interest, as it suggests the scale of grand unified physics, governs whether cosmological events such as topological defect formation can occur after inflation, and also determines the amplitude of gravitational waves which may be detectable using interferometers. The COBE results are used to limit the energy scale of inflation at the time large scale perturbations were imprinted. An exact dynamical treatment based on the Hamilton-Jacobi equations is then used to translate this into limits on the energy scale at the end of inflation. General constraints are given, and then tighter constraints based on physically motivated assumptions regarding the allowed forms of density perturbation and gravitational wave spectra. These are also compared with the values of familiar models.