2017/03/27 by Yingru Xu, Pierre Moreau, Taesoo Song +3
Physics and Astronomy · #Dust and Plasma Wave Phenomena #Dynamics (music) #Flow (mathematics) #High-Energy Particle Collisions Research #Momentum (technical analysis) #Non-equilibrium thermodynamics #Observable #Pulsars and Gravitational Waves Research #Steady state (chemistry) #Thermodynamic equilibrium #Viscosity #Volume viscosity #nucl-th
paper · pdf · doi:10.1103/physrevc.96.024902
published as Phys. Rev. C 96, 024902 (2017) · 19 pages, 16 figures
arxiv created 2017/03/27 · openalex publication_date 2017/08/08 · arxiv updated 2017/08/16 · openalex created_date 2017/08/17 · openalex updated_date 2026/08/05
The impact of nonequilibrium effects on the dynamics of heavy-ion collisions is investigated by comparing a nonequilibrium transport approach, the Parton-Hadron-String-Dynamics (PHSD), to a 2D+1 viscous hydrodynamical model, which is based on the assumption of local equilibrium and conservation laws. Starting the hydrodynamical model from the same nonequilibrium initial condition as in the PHSD, using an equivalent lQCD equation of state (EoS), the same transport coefficients, i.e., shear viscosity \ensuremathη and the bulk viscosity \ensuremathζ in the hydrodynamical model, we compare the time evolution of the system in terms of energy density, Fourier transformed energy density, spatial and momentum eccentricities, and ellipticity to quantify the traces of nonequilibrium phenomena. In addition, we also investigate the role of initial pre-equilibrium flow on the hydrodynamical evolution and demonstrate its importance for final state observables. We find that because of nonequilibrium effects, the event-by-event transport calculations show large fluctuations in the collective properties, while ensemble averaged observables are close to the hydrodynamical results.