... argument if the inflaton is interacting with a thermal bath at a temperature, T , with all particles including the inflaton in thermal equilibrium and relativistic, then the decay width of the inflaton ... temperatures in the early Universe To date particle physics has mainly focussed on the equilibrium properties of such scalar fields in the broken and unbroken phases, however the interactions of the scalar ... Scalar fields: fluctuating and dissipating in the early Universe N I V E R S T H Y IT E U G H O F R E D I U N B Sam Bartrum A thesis submitted in fulfilment of the requirements for the degree...