Speaker
Description
So far a major source of uncertainty in the study of heavy-ion collisions arises from the early time dynamics which includes initial state and pre-equilibrium dynamics. The state-of-the-art framework, \kompost~\cite{Kurkela:2018vqr,Kurkela:2018wud}, employs non-equilibrium Green's functions to propagate the initial energy-momentum tensor to the hydrodynamic phase, yet currently only treats transverse plane dynamics under boost-invariant conditions.
In this work, we extend \kompost\ to include non-boost-invariant responses to initial conditions, essential for accurately capturing the longitudinal structures observed in heavy-ion collisions.
Non-boost-invariant fluctuations on top of a homogeneous background are evolved using (3+1)D response functions calculated in kinetic theory.
To assess kinetic theory's transition towards hydrodynamic evolution, we systematically compare the out-of-equilibrium shear-stress tensor from \kompost-3D with estimates based on Navier-Stokes hydrodynamics.
Subsequently, a comprehensive (3+1)D framework, \Dipper+\kompost-3D+CLVisc+SMASH, is utilized to simulate the complete spacetime evolution of heavy-ion collisions.
The sensitivity of key observables, including longitudinal structure of anisotropic flow, to variations in the hydrodynamic initialization time is thoroughly investigated.