Closing in on “Perfection”

In a recent preprint

Song, Bass, Heinz, Hirano, and Shen present systematic comparisons of RHIC data on elliptic flow in Au+Au collisions with a hybrid model of the reaction dynamics. They conclude that the kinematic shear viscosity ν = 4πη/s in the quark-gluon plasma phase of the reaction does not exceed 2.5 on average, compared with the lower KSS bound of 1. (more…)


Over the past few months a new initiative, called Theory-Experiment Collaboration for Hot QCD Matter (TECHQM), has taken shape, which potentially will have great impact on how our community arrives at scientific conclusions on the nature and properties of hot and dense QCD matter created at the RHIC and LHC facilities. (more…)

What a Difference a Term Makes

The recent post on the AMO competition for perfect fluidity offers a wonderful opportunity to compare and contrast the techniques of condensed matter physics versus those of relativistic heavy ion physics. (more…)

Microscopic Transport Model Primer

Microscopic transport models aim at describing the time-evolution of a heavy-ion collision, either in part or from beginning to end, using microscopic degrees of freedom, i.e. nucleons, hadrons or quarks and gluons. They are based on the solution of a transport equation, which can be derived within the framework of kinetic theory. (more…)

Recent Hydro Developments

Improving the application of Relativistic Fluid Dynamics to relativistic heavy-ion collisions is an ongoing challenge and currently a very active area of research: recent notable preprints on the topic are centered around two main themes: (more…)