Measuring infrared contributions to the QCD pressure

TL;DR

This paper combines analytical and 3D lattice methods to accurately compute the QCD pressure from twice the critical temperature to very high temperatures, addressing limitations of perturbation theory.

Contribution

It introduces a novel combined approach that extends the calculation of QCD pressure into high-temperature regimes with improved accuracy.

Findings

Accurate computation of QCD pressure from 2 T_c to infinity.

Resolution of logarithmic contributions related to 4-loop perturbation theory.

Demonstrates the feasibility of combining analytical and lattice methods for thermodynamic quantities.

Abstract

For the pressure (or free energy) of QCD, four-dimensional (4d) lattice data is available at zero baryon density up to a few times the critical temperature $T_c$. Perturbation theory, on the other hand, has serious convergence problems even at very high temperatures. In a combined analytical and three-dimensional (3d) lattice method, we show that it is possible to compute the QCD pressure from about $2 T_c$ to infinity. The numerical accuracy is good enough to resolve in principle, e.g., logarithmic contributions related to 4-loop perturbation theory.