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

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 Källén-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 ${\varphi }^4$ theory, establishing its leading behaviour in the small and large coupling regimes.

21 pages, 3 figures; v3: additional references added as well as some minor text changes, matches published version

References in corpus (4)

• A calculation of the bulk viscosity in SU(3) gluodynamics
• Flow equations for spectral functions at finite external momenta
• Spectral functions in the ${\varphi }^4$-theory from the spectral DSE
• Fermionic excitations at finite temperature and density

Cited by in corpus (8)

• The Present and Future of QCD
• Pion spectral properties above the chiral crossover of QCD
• Chiral spin symmetry and hot/dense QCD
• Pseudo-scalar meson spectral properties in the chiral crossover region of QCD
• Euclidean thermal correlation functions in local QFT
• Real-time observables from Euclidean thermal correlation functions
• Shear viscosity from perturbative Quantum Chromodynamics to the hadron resonance gas at finite baryon, strangeness, and electric charge densities
• Non-perturbative BRST symmetry and the spectral structure of the ghost propagator