Quasi-particle model for lattice QCD: quark–gluon plasma in heavy ion collisions

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2009-11, Vol.64 (1), p.63-72, Article 63
• Main Authors: Chandra, Vinod, Ravishankar, V.
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic collisions; Density ratio; Dispersions; Distribution functions; Elementary Particles; Entropy; Equations of state; Exact sciences and technology; Flux density; Fugacity; Gauge theory; Gluons; Hadrons; Heavy Ions; Ionic collisions; Lattices; Mapping; Mathematical models; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Particle energy; Physics; Physics and Astronomy; Quantum chromodynamics; Quantum Field Theories; Quantum Field Theory; Quark-gluon plasma; Regular Article - Theoretical Physics; Shear viscosity; String Theory; The physics of elementary particles and fields; Viscosity
• ISSN: 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-009-1126-8

We propose a quasi-particle model to describe the lattice QCD equation of state for pure SU(3) gauge theory in its deconfined state, for T ≥1.5 T c . The method involves mapping the interaction part of the equation of state to an effective fugacity of otherwise non-interacting quasi-gluons. We find that this mapping is exact. Using the quasi-gluon distribution function, we determine the energy density and the modified dispersion relation for the single particle energy, in which the trace anomaly is manifest. As an application, we first determine the Debye mass, and then the important transport parameters, viz., the shear viscosity, η , and the shear viscosity to entropy density ratio, . We find that both η and are sensitive to the interactions, and that the interactions significantly lower both η and .