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In this report we present our calculation of the transport coefficient of gluon system on $24^3\times 8$ lattice in the quench approximation. Simulations are carried out in the range, $1.4 \le T/T_c \le 24$. In the temperature region…

High Energy Physics - Lattice · Physics 2007-05-23 Sunao Sakai , Atsushi Nakamura

The quark gluon plasma produced in heavy ion collisions behaves like an almost ideal fluid described by viscous hydrodynamics with a number of transport coefficients. The second order coefficient $\kappa$ is related to a Euclidean…

High Energy Physics - Lattice · Physics 2015-06-18 Owe Philipsen , Christian Schäfer

Among the key features of hot and dense QCD matter produced in ultra-relativistic heavy-ion collisions at RHIC is its very low shear viscosity, indicative of the properties of a near-ideal fluid, and a large opacity demonstrated by jet…

Nuclear Theory · Physics 2010-12-09 John Fuini , Nasser S. Demir , Dinesh K. Srivastava , Steffen A. Bass

We calculate the shear viscosity $\eta$ in the quark-gluon plasma (QGP) phase within a virial expansion approach with particular interest in the ratio of $\eta$ to the entropy density $s$, i.e. $\eta/s$. The virial expansion approach allows…

High Energy Physics - Phenomenology · Physics 2011-02-09 S. Mattiello , W. Cassing

In order to describe properties of an equilibrated quark-gluon plasma, QCD at finite temperature (and density) has to be considered. Besides lattice calculations, which can be applied only to static quantities at zero density, perturbative…

High Energy Physics - Phenomenology · Physics 2009-10-31 Markus H. Thoma

The shear viscosity to entropy density ratio ({\eta}/s) of quark gluon plasma produced in ultra- relativistic heavy-ion collisions has been studied from the energy loss of heavy quarks in QGP medium. We have also studied the bulk viscosity…

High Energy Physics - Phenomenology · Physics 2018-03-13 Ashik Ikbal Sheikh , Zubayer Ahammed

The specific shear viscosity (eta/s)_QGP of a Quark-Gluon-Plasma (QGP) at temperatures T_c < T < 2T_c is extracted from the centrality dependence of the eccentricity-scaled elliptic flow measured in ultra-relativistic heavy-ion collisions.…

Nuclear Theory · Physics 2011-05-23 Huichao Song , Steffen A. Bass , Ulrich W. Heinz , Tetsufumi Hirano , Chun Shen

The shear ($\eta$) and bulk ($\zeta$) viscous coefficients have been evaluated for a gluonic fluid. The elastic, $gg \rightarrow gg$ and the inelastic, number non-conserving, $gg\rightarrow ggg$ processes have been considered as the…

Nuclear Theory · Physics 2011-06-15 Santosh K Das , Jan-e Alam

One of the most striking results from the Relativistic Heavy Ion Collider is the strong elliptic flow. This review summarizes what is observed and how these results are combined with reasonable theoretical assumptions to estimate the shear…

Nuclear Theory · Physics 2016-12-21 Derek A. Teaney

We use the Chapman-Enskog method to investigate the shear viscosity of the quark-gluon plasma with a focus on its relation to parton cross sections. We use the recently obtained analytical expression for the shear viscosity $\eta$ of a…

Nuclear Theory · Physics 2026-04-29 Okey Ohanaka , Zi-Wei Lin

Current experiments at the Relativistic Heavy Ion Collider (RHIC) are probing finite baryon densities where the shear viscosity to enthalpy ratio $\eta T/w$ of the Quark Gluon Plasma remains unknown. We use the Hadron Resonance Gas (HRG)…

The quark--gluon plasma produced in relativistic heavy--ion collisions behaves as a nearly perfect fluid characterized by an exceptionally small shear viscosity to entropy density ratio. Understanding the microscopic origin of this small…

High Energy Physics - Phenomenology · Physics 2026-03-17 Debmalya Mukhopadhyay

Experimental results obtained at the Relativistic Heavy Ion Collider (RHIC) have been interpreted in terms of a strongly interacting quark gluon plasma. The strongly interacting plasma is characterized by ``perfect fluidity'', i.e. a ratio…

Nuclear Theory · Physics 2007-07-11 Thomas Schaefer

A set of kinetic equations is used to study equilibration of the anisotropic quark-gluon plasma produced by decays of color flux tubes possibly created at the very early stages of ultra-relativistic heavy-ion collisions. The decay rates of…

High Energy Physics - Phenomenology · Physics 2013-08-28 Radoslaw Ryblewski , Wojciech Florkowski

It was recently conjectured that the ratio of the shear viscosity to entropy density, $ \eta/ s$, for any fluid always exceeds $\hbar/(4 \pi k_B)$. This conjecture was motivated by quantum field theoretic results obtained via the AdS/CFT…

High Energy Physics - Theory · Physics 2008-11-26 Thomas D. Cohen

This thesis is mainly devoted to the study of thermodynamics for quantum Chromodynamics. In this thesis I apply hard-thermal-loop perturbation theory, which is a gauge-invariant reorganization of the conventional perturbative expansion for…

High Energy Physics - Phenomenology · Physics 2015-01-30 Najmul Haque

We extract the shear viscosity to entropy density ratio \eta/s of cold fermionic atoms in the unitarity limit from experimental data on the damping of collective excitations. We find that near the critical temperature \eta/s is roughly…

Other Condensed Matter · Physics 2008-11-26 Thomas Schaefer

We derive an expression relating the transport parameter $\hat{q}$ and the shear viscosity $\eta$ of a weakly coupled quark-gluon plasma. A deviation from this relation can be regarded as a quantitative measure of ``strong coupling'' of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Majumder , B. Müller , X. -N. Wang

One of the most remarkable features of the Quark Gluon Plasma is its nearly perfect fluidity behavior indicated by the small shear viscosity to entropy density ratio obtained from fitting relativistic viscous hydrodynamics flow harmonics to…

Nuclear Theory · Physics 2015-12-22 Jacquelyn Noronha-Hostler

We compute the bulk, $\zeta$, and shear, $\eta$, viscosity over entropy density, $s$, for the QCD matter formed in small collision systems at LHC. We consider a scenario of the String Percolation Model by proposing a global form of the…

High Energy Physics - Phenomenology · Physics 2023-12-06 J. R. Alvarado García , I. Bautista , A. Fernández Téllez , P. Fierro