Multifield Reheating and the Fate of the Primordial Observables

Ewan Tarrant

February 01, 2013

–

Abstract: The presence of additional light fields during inflation can source isocurvature fluctuations, which can cause the curvature perturbation $ zeta$, and its statistics to evolve on superhorizon scales. I will demonstrate that if these fluctuations have not completely decayed before the onset of perturbative reheating, then primordial observables such as the level of non–Gaussianity can develop substantial reheating dependant corrections. I will argue that for inflationary models where an adiabatic condition is not reached before the relevant fields begin to decay, we must be careful in our interpretation of any observational constraints that place bounds on the statistics of $ zeta$.