Joint cosmology seminar at Tufts:

Tuesday, October 28, 2014, 2:30 pm
Robinson Hall, Room 250
Tufts University
Refreshments at 2:00 in Knipp Library, Room 251

Entropy mode loops in reheating and cosmological perturbations

Ali Kaya
Bogazici University, Istanbul


The conservation of the curvature perturbation on superhorizon scales is an important feature for the inflationary predictions to hold. We show that in scalar field inflationary models, entropy mode loop corrections during reheating, which correspond to the inflaton decay products, can cause nontrivial superhorizon evolution of the curvature perturbation. Similarly, entropy mode loops are shown to produce significant non-gaussianity and modify the tensor power spectrum meaningfully. The effect becomes prominent when reheating occurs via parametric resonance (preheating), even indicating the breakdown of the perturbation theory, as we demonstrate in a specific chaotic model.