Constraining the onset of viscous hydrodynamics

TL;DR

This paper develops criteria to determine the earliest time when second-order conformal viscous hydrodynamics can be applied in relativistic heavy-ion collisions, with explicit derivations for 0+1 dimensions and discussions for higher dimensions.

Contribution

It introduces general constraints on the initial time for viscous hydrodynamics onset, extending previous understanding to higher dimensions beyond 0+1.

Findings

Derived two criteria for constraining hydrodynamics onset

Explicitly applied constraints to 0+1 dimensional case

Discussed extension of constraints to higher dimensions

Abstract

We derive two general criteria that can be used to constrain the initial time of the onset of 2nd-order conformal viscous hydrodynamics in relativistic heavy-ion collisions. We show this explicitly for 0+1 dimensional viscous hydrodynamics and discuss how to extend the constraint to higher dimensions.