Thermal Inflation with a Thermal Waterfall Scalar Field Coupled to a Light Spectator Scalar Field Arron Rumsey September 2016 This thesis is submitted in partial fulfillment of the requirements for the degree of Master of Philosophy (MPhil) at Lancaster University. No part of this thesis has been previously submitted for the award of a higher degree. arXiv:1610.00146v1 [astro-ph.CO] 1 Oct 2016