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arXiv · 2104.13413

Spectral representation of the shear viscosity for local scalar QFTs at finite temperature

Peter Lowdon·Ralf-Arno Tripolt·Jan M. Pawlowski·Dirk H. Rischke
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Abstract

In local scalar quantum field theories (QFTs) at finite temperature correlation functions are known to satisfy certain non-perturbative constraints, which for two-point functions in particular implies the existence of a generalisation of the standard K\"{a}ll\'{e}n-Lehmann representation. In this work, we use these constraints in order to derive a spectral representation for the shear viscosity arising from the thermal asymptotic states, $\eta_{0}$. As an example, we calculate $\eta_{0}$ in $\phi^{4}$ theory, establishing its leading behaviour in the small and large coupling regimes.

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Peter Lowdon, Ralf-Arno Tripolt, Jan M. Pawlowski, Dirk H. Rischke. 2021-04-27. Spectral representation of the shear viscosity for local scalar QFTs at finite temperature. https://doi.org/10.1103/physrevd.104.065010

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