Second Order Perturbations During Inflation Beyond Slow-roll
Huston, Ian (Queen Mary, University of London)

Cosmological perturbation theory is well established as a tool for probing the inhomogeneities of the early universe. In this talk I will motivate the use of perturbation theory and outline the mathematical formalism. Perturbations beyond linear order are especially interesting as non-Gaussian effects can be used to constrain inflationary models. I will show how the Klein-Gordon equation at second order, written in terms of scalar field variations only, can be numerically solved. This procedure allows the evolution of second order perturbations in general without the need for any slow roll approximation. The numerical software is being extended to deal with multiple fields and I will describe how this will increase the range of models which can be tested.