NBIA Workshop: Field Theory and Cosmology – Niels Bohr Institute - University of Copenhagen

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NBIA Workshop: Field Theory and Cosmology

Quantum and thermal backreaction from interactions during inflation

Anders Tranberg (University of Oulu)



Inflation can be described in terms of a single scalar degree of freedom (a homogeneous mean field) rolling in a suitable effective potential. Still, we know that the inflaton must be coupled to other fields, that these will contribute to the effective inflaton potential and possibly introduce dissipation. To extract all of these effects, the coupled system must ideally be treated using out-of-equilibrium quantum field theory. I will describe how to systematically build up and improve approximations within the so-called "2PI" framework. I will apply this to particle creation and backreaction during and at the end of inflation, and comment on the scenario of Warm Inflation.