Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Early Time Dynamics in Heavy Ion Collisions from CGC and from AdS/CFT   We review two different theoretical approaches to the strong interaction
dynamics at the early times immediately following heavy ion collisions. One
approach is based on small-coupling physics of the Color Glass Condensate
(CGC). The other approach is based on Anti-de Sitter space/Conformal Field
Theory (AdS/CFT) correspondence and may be applicable to describing
large-coupling QCD interactions. We point out that in terms of theoretical
tools the two approaches are somewhat similar: in CGC one deals with classical
gluon fields produced in a nuclear shock wave collision, while in AdS/CFT one
studies classical gravity in a gravitational shock wave collision. We stress,
however, that the resulting physics is different: the classical gluon fields in
CGC lead to a free-streaming medium produced in heavy ion collisions, while the
classical gravity in the 5-dimensional AdS bulk is likely to lead to ideal
hydrodynamics description of the produced medium. Also, the valence quarks in
colliding nuclei in CGC continue along their light cone trajectories after the
collision with very little recoil, while we show that in AdS the colliding
nuclei are likely to lose most of their energy in the collision and stop.

26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom