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arXiv · 1710.06118

A quantum heating as an alternative of reheating

Emil T. Akhmedov·Francesco Bascone
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Abstract

To model a realistic situation for the beginning we consider massive real scalar $ϕ^4$ theory in a (1+1)-dimensional asymptotically static Minkowski spacetime with an intermediate stage of expansion. To have an analytic headway we assume that scalars have a big mass. At past and future infinities of the background we have flat Minkowski regions which are joint by the inflationary expansion region. We use the tree-level Keldysh propagator in the theory in question to calculate the expectation value of the stress-energy tensor which is, thus, due to the excitations of the zero-point fluctuations. Then we show that even for large mass, if the de Sitter expansion stage is long enough, the quantum loop corrections to the expectation value of the stress-energy tensor are not negligible in comparison with the tree-level contribution. That is revealed itself via the excitation of the higher-point fluctuations of the exact modes: During the expansion stage a non-zero particle number density for the exact modes is generated. This density is not Plankian and serves as a quench which leads to a thermalization in the out Minkowski stage.

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Emil T. Akhmedov, Francesco Bascone. 2018-01-18. A quantum heating as an alternative of reheating. https://doi.org/10.1103/physrevd.97.045013

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