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Title: Equilibration and hydrodynamics at strong and weak coupling

Abstract

We give an updated overview of both weak and strong coupling methods to describe the approach to a plasma described by viscous hydrodynamics, a process now called hydrodynamisation. At weak coupling the very first moments after a heavy ion collision is described by the colour-glass condensate framework, but quickly thereafter the mean free path is long enough for kinetic theory to become applicable. Recent simulations indicate thermalization in a time t ~ 40 (η/s) 4/3/ T, with $$\tau$$ the temperature at that time and η/s the shear viscosity divided by the entropy density. At (infinitely) strong coupling it is possible to mimic heavy ion collisions by using holography, which leads to a dual description of colliding gravitational shock waves. The plasma formed hydrodynamises within a time of 0.41/$$\tau$$ recent extension found corrections to this result for finite values of the coupling, when is bigger than the canonical value of 1/4$$\pi$$, which leads to t ~ (.41+1.6(η/s-1/4$$\pi$$))/ T. Moreover, future improvements include the inclusion of the effects of the running coupling constant in QCD.

Authors:
 [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Univ. of Utrecht, Utrecht (Netherlands)
Publication Date:
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1500558
Grant/Contract Number:  
SC0011090
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Physics. A
Additional Journal Information:
Journal Volume: 967; Journal Issue: C; Journal ID: ISSN 0375-9474
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; hydrodynamisation; holography

Citation Formats

van der Schee, Wilke. Equilibration and hydrodynamics at strong and weak coupling. United States: N. p., 2017. Web. doi:10.1016/j.nuclphysa.2017.05.003.
van der Schee, Wilke. Equilibration and hydrodynamics at strong and weak coupling. United States. doi:10.1016/j.nuclphysa.2017.05.003.
van der Schee, Wilke. Mon . "Equilibration and hydrodynamics at strong and weak coupling". United States. doi:10.1016/j.nuclphysa.2017.05.003. https://www.osti.gov/servlets/purl/1500558.
@article{osti_1500558,
title = {Equilibration and hydrodynamics at strong and weak coupling},
author = {van der Schee, Wilke},
abstractNote = {We give an updated overview of both weak and strong coupling methods to describe the approach to a plasma described by viscous hydrodynamics, a process now called hydrodynamisation. At weak coupling the very first moments after a heavy ion collision is described by the colour-glass condensate framework, but quickly thereafter the mean free path is long enough for kinetic theory to become applicable. Recent simulations indicate thermalization in a time t ~ 40 (η/s)4/3/T, with $\tau$ the temperature at that time and η/s the shear viscosity divided by the entropy density. At (infinitely) strong coupling it is possible to mimic heavy ion collisions by using holography, which leads to a dual description of colliding gravitational shock waves. The plasma formed hydrodynamises within a time of 0.41/$\tau$ recent extension found corrections to this result for finite values of the coupling, when is bigger than the canonical value of 1/4$\pi$, which leads to t ~ (.41+1.6(η/s-1/4$\pi$))/T. Moreover, future improvements include the inclusion of the effects of the running coupling constant in QCD.},
doi = {10.1016/j.nuclphysa.2017.05.003},
journal = {Nuclear Physics. A},
number = C,
volume = 967,
place = {United States},
year = {2017},
month = {9}
}

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Figures / Tables:

Fig. 1. Fig. 1. : Left we show relaxation times $τ$ as a function of the ’t Hooft coupling $λ$ for a partially resummed supersymmetric Yang-Mills theory, in units of the temperature $T$ and the viscosity over entropy ratio η/s (from [11], see also [12]). Even though the η/s ranges from 0.08more » to 1.05 in the range plotted, the ratio is remarkably constant. Right we show the relaxation of the energy density for a particular evolution using gluonic kinetic theory (from [13]), for $λ$ = 10 (i.e. η/s ≈ 0.6 [14]). It can be seen that the system is well described by (viscous) hydrodynamics within approximately 2 fm/c.« less

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.