Non-perturbative thermal QCD at very high temperatures

TL;DR

This paper introduces a novel non-perturbative approach to study thermal QCD at very high temperatures, utilizing step scaling and shifted boundary conditions to efficiently compute the hadronic screening spectrum up to 160 GeV.

Contribution

It presents a new strategy combining step scaling and shifted boundary conditions for non-perturbative thermal QCD studies at high temperatures.

Findings

Computed hadronic screening spectrum for N_f=3 at T from 1 GeV to 160 GeV.

Demonstrated the effectiveness of the method in controlling finite volume effects.

Avoided zero temperature subtraction in the equation of state calculations.

Abstract

We present a recently introduced strategy to study non-perturbatively thermal QCD up to temperatures of the order of the electro-weak scale, combining step scaling techniques and shifted boundary conditions. The former allow to renormalize the theory for a range of scales which spans several orders of magnitude with a moderate computational cost. Shifted boundary conditions avoid the need for the zero temperature subtraction in the Equation of State. As a consequence, the simulated lattices do not have to accommodate two very different scales, the pion mass and the temperature. Effective field theory arguments guarantee that finite volume effects can be kept under control safely. As a first application of this strategy, we present the results of the computation of the hadronic screening spectrum in QCD with $N_f=3$ flavours of massless quarks for temperatures from $T\sim 1$ GeV up to $\sim 160$ GeV.