13-19 May 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

(3+1)D Viscous Anisotropic Hydrodynamics for Nonconformal Fluids

16 May 2018, 10:00
Sala Casinò, 1st Floor (Palazzo del Casinò)

Sala Casinò, 1st Floor

Palazzo del Casinò

Parallel Talk New theoretical developments New theoretical developments


Mike McNelis (The Ohio State University)


Anisotropic hydrodynamics improves upon standard dissipative fluid dynamics by treating certain large dissipative corrections non-perturbatively. Relativistic heavy-ion collisions feature two such large dissipative effects: (i) Strongly anisotropic expansion generates a large shear stress component which manifests itself in very different longitudinal and transverse pressures, especially at early times. (ii) Critical fluctuations near the quark-hadron phase transition lead to a large bulk viscous pressure on the conversion surface between hydrodynamics and a microscopic hadronic cascade description of the final collision stage.

We present a new dissipative hydrodynamic formulation for non-conformal fluids where both of these effects are treated nonperturbatively. The evolution equations are derived from the Boltzmann equation in the 14-moment approximation, using an expansion around an anisotropic leading-order distribution function with two momentum-space deformation parameters, accounting for the longitudinal and transverse pressures. Generalized Landau matching conditions for the longitudinal and transverse pressures are then required to obtain their evolution. We describe an approximate anisotropic equation of state that relates the anisotropy parameters with the macroscopic pressures. Residual shear stresses are smaller and are treated perturbatively, as in standard second-order dissipative fluid dynamics.

The resulting optimized viscous anisotropic hydrodynamic evolution equations are derived in 3+1 dimensions and tested in a (0+1)-dimensional Bjorken expansion, using an updated lattice equation of state. Comparisons with other viscous hydrodynamical frameworks are presented.

Content type Theory
Centralised submission by Collaboration Presenter name already specified

Primary author

Mike McNelis (The Ohio State University)


Dennis Bazow Ulrich Heinz (The Ohio State University)

Presentation Materials