$T$-Matrix Approach to Strongly Coupled QGP

TL;DR

This paper develops a thermodynamic $T$-matrix approach to extract the inter-quark potential in the QGP from lattice data, computes heavy-quark transport coefficients, and derives the QGP equation of state, revealing strongly coupled, non-quasi-particle behavior.

Contribution

It introduces a novel $T$-matrix method to determine the inter-quark potential from lattice QCD and applies it to compute transport coefficients and the QGP equation of state.

Findings

The potential $V$ is extracted from lattice QCD free energy fits.

Heavy-quark transport coefficients are computed using the new potential.

The QGP exhibits large thermal widths, indicating dissolution of quasi-particles.

Abstract

Based on a thermodynamic $T$-matrix approach we extract the potential $V$ between two static charges in the quark-gluon plasma (QGP) from fits to the pertinent lattice-QCD free energy. With suitable relativistic corrections we utilize this new potential to compute heavy-quark transport coefficients and compare the results to previous calculations using either $F$ or $U$ as potential. We then discuss a generalization of the $T$-matrix re-summation to a "matrix $\log$" re-summation of $t$-channel diagrams for the grand partition function of the QGP in the Luttinger-Ward skeleton diagram formalism. With $V$ as a non-perturbative driving kernel in the light-parton sector, we obtain the QGP equation of state from fits to lattice-QCD data. The resulting light-parton spectral functions are characterized by large thermal widths at small momenta, indicating the dissolution of quasi-particles in a strongly coupled QGP.