Relativistic anisotropic hydrodynamics

TL;DR

This paper reviews recent advances in relativistic anisotropic hydrodynamics, demonstrating its effectiveness in modeling quark-gluon plasma dynamics and comparing well with exact solutions and experimental data.

Contribution

It introduces a second-order viscous anisotropic hydrodynamics framework with non-spheroidal corrections and applies it to phenomenological heavy-ion collision data.

Findings

Anisotropic hydrodynamics best reproduces exact Boltzmann solutions.

The framework effectively models the momentum-space anisotropic QGP.

Simulation results agree with LHC experimental data.

Abstract

In this paper we review recent progress in relativistic anisotropic hydrodynamics. We begin with a pedagogical introduction to the topic which takes into account the advances in our understanding of this topic since its inception. We consider both conformal and non-conformal systems and demonstrate how one can implement a realistic equation of state using a quasiparticle approach. We then consider the inclusion of non-spheroidal (non-ellipsoidal) corrections to leading-order anisotropic hydrodynamics and present the findings of the resulting second-order viscous anisotropic hydrodynamics framework. We compare the results obtained in both the conformal and non-conformal cases with exact solutions to the Boltzmann equation and demonstrate that, in all known cases, anisotropic hydrodynamics best reproduces the exact solutions. Based on this success, we then discuss the phenomenological application of anisotropic hydrodynamics. Along these lines, we review techniques which can be used to convert a momentum-space anisotropic fluid into hadronic degrees of freedom by generalizing the original idea of Cooper-Frye freeze-out to momentum-space anisotropic systems. And, finally, we present phenomenological results of 3+1d quasiparticle anisotropic hydrodynamic simulations and compare them to experimental data produced in 2.76 TeV Pb-Pb collisions at the LHC. Our results indicate that anisotropic hydrodynamics provides a promising framework for describing the dynamics of the momentum-space anisotropic QGP created in heavy-ion collisions.