Thermal Correlators in the \rho\ channel of two-flavor QCD

TL;DR

This study uses lattice QCD to analyze the vector correlator in the high-temperature phase of two-flavor QCD, providing insights into spectral functions and electrical conductivity.

Contribution

It introduces a combined analysis of spectral functions using sum rules and direct fits, offering new estimates of electrical conductivity in the quark-gluon plasma.

Findings

Good agreement between different spectral function fits below two-pion threshold

Estimate of electrical conductivity consistent with theoretical expectations

Analysis confirms the spectral function's smoothness in the low-frequency region

Abstract

We present a lattice QCD calculation with two dynamical flavors of the isovector vector correlator in the high-temperature phase. We analyze the correlator in terms of the associated spectral function, for which we review the theoretical expectations. In our main analysis, we perform a fit for the difference of the thermal and vacuum spectral functions, and we use an exact sum rule that constrains this difference. We also perform a direct fit for the thermal spectral function, and obtain good agreement between the two analyses for frequencies below the two-pion threshold. Under the assumption that the spectral function is smooth in that region, we give an estimate of the electrical conductivity.