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Effects of weak self-interactions in a relativistic plasma on cosmological perturbations

H. Nachbagauer·A. K. Rebhan·D. J. Schwarz
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Abstract

The exact solutions for linear cosmological perturbations which have been obtained for collisionless relativistic matter within thermal field theory are extended to a self-interacting case. The two-loop contributions of scalar $λϕ^4$ theory to the thermal graviton self-energy are evaluated, which give the $O(λ)$ corrections in the perturbation equations. The changes are found to be perturbative on scales comparable to or larger than the Hubble horizon, but the determination of the large-time damping behavior of subhorizon perturbations requires a resummation of thermally induced masses.

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H. Nachbagauer, A. K. Rebhan, D. J. Schwarz. 1994-11-30. Effects of weak self-interactions in a relativistic plasma on cosmological perturbations. https://doi.org/10.1103/physrevd.51.2504

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