Complexified boost invariance and holographic heavy ion collisions

Abstract

At strong coupling holographic studies have shown that heavy ion collisions do not obey normal boost invariance. Here we study a modified boost invariance through a complex shift in time, and show that this leads to surprisingly good agreement with numerical holographic computations. When including perturbations the agreement becomes even better, both in the hydrodynamic and the far-from-equilibrium regime. One of the main advantages is an analytic formulation of the stress-energy tensor of the longitudinal dynamics of holographic heavy ion collisions.

QCD thermalization: Ab initio approaches and interdisciplinary connections

“…projectiles is not boost invariant even when they are infinitely thin. The extent to which this is the case was explored in [24] and, quite remarkably, the results fit well [545] with complex deformations of the purely boost invariant flow introduced in [546].…”

Early thermalization, hydrodynamics and energy loss in AdS/CFT

“…68 Curiously, for the high energy shocks there seems to be a reasonably accurate analytic formulation -at least at small rapidities -by using a complexified boost symmetry, even valid in the far-from-equilibrium regime. 69 At later times the low and high energy collisions behave similarly though; they both thermalize fast (shown in figure 5) and deposit all their energy into the plasma.…”

Rapidity dependence in holographic heavy ion collisions

“…where η 0 = 1 √ 2 3 3/4 , we take N c = 1.8 such that the EOS matches lattice data (e/T 4 ≈ 12) [27,28] and Λ has to be extracted from Fig. 1 numerically as Λ = 0.37 1/3 [29], with = √ L R the center of mass energy density per transverse area of the collision (all quantities depend on x ⊥ ). Eq.…”