Charge transport and vector meson dissociation across the thermal phase transition in lattice QCD with two light quark flavors

TL;DR

This study investigates how charge transport and vector meson properties change across the deconfinement transition in lattice QCD with two light quark flavors, revealing meson dissociation and estimating electrical conductivity.

Contribution

It provides the first lattice QCD analysis of spectral functions and electrical conductivity across the deconfinement transition using novel sum rule and model-independent methods.

Findings

Evidence for $ ho$ meson dissociation at high temperatures.

Estimated electrical conductivity increases across the phase transition.

Comparison of lattice results with kinetic theory and phenomenological models.

Abstract

We compute and analyze correlation functions in the isovector vector channel at vanishing spatial momentum across the deconfinement phase transition in lattice QCD. The simulations are carried out at temperatures $T/T_c=0.156, 0.8, 1.0, 1.25$ and $1.67$ with $T_c\simeq203$MeV for two flavors of Wilson-Clover fermions with a zero-temperature pion mass of $\simeq270$MeV. Exploiting exact sum rules and applying a phenomenologically motivated ansatz allows us to determine the spectral function $\rho(\omega,T)$ via a fit to the lattice correlation function data. From these results we estimate the electrical conductivity across the deconfinement phase transition via a Kubo formula and find evidence for the dissociation of the $\rho$ meson by resolving its spectral weight at the available temperatures. We also apply the Backus-Gilbert method as a model-independent approach to this problem. At any given frequency, it yields a local weighted average of the true spectral function. We use this method to compare kinetic theory predictions and previously published phenomenological spectral functions to our lattice study.