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Related papers: Shear Viscosity in a Gluon Gas

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Hydrodynamics predicts long-lived sound and shear waves. Thermal fluctuations in these waves can lead to the diffusion of momentum density, contributing to the shear viscosity and other transport coefficients. Within viscous hydrodynamics…

High Energy Physics - Phenomenology · Physics 2011-08-04 Pavel Kovtun , Guy D. Moore , Paul Romatschke

The shear ($\eta$) and bulk ($\zeta$) viscosities are calculated in a quasiparticle relaxation time approximation for a hadron matter described within the relativistic mean-field based model with scaled hadron masses and couplings.…

Nuclear Theory · Physics 2011-05-05 A. S. Khvorostukhin , V. D. Toneev , D. N. Voskresensky

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

The shear viscosity tensor of the superfluid Fermi gas in p-wave state with weak interaction is calculated at low temperatures, by using the Boltzmann equation approach. We consider the transition probabilities for the binary, decay and…

Quantum Gases · Physics 2016-03-09 Soudabe Nasirimoghadam , Roohollah Aliabadi , Mohamad Ali Shahzamanian

We precisely measure the shear viscosity for a resonantly interacting Fermi gas as a function of temperature, from nearly the ground state through the superfluid phase transition at a critical temperature $T_c$. Using an iterative method to…

Quantum Gases · Physics 2015-07-15 J. A. Joseph , E. Elliott , J. E. Thomas

We consider $O(N)$ $g\varphi^4$ theory with the coupling $g$ being large, and calculate shear viscosity to entropy density ratio ($\eta/s$). The final result for $\eta/s$ has a form remarkably similar to that obtained from string theory…

High Energy Physics - Phenomenology · Physics 2016-05-23 Namit Mahajan

We compute the contribution of phonons to the shear viscosity $\eta$ in superfluid neutron stars, assuming neutron pairing in a $^1S_0$ channel. We use a Boltzmann equation amended by a collision term that takes into account the binary…

Solar and Stellar Astrophysics · Physics 2013-05-29 Cristina Manuel , Laura Tolos

Nuclear multifragmentation in intermediate energy heavy ion collisions has long been associated with liquid-gas phase transition. We calculate the shear viscosity to entropy density ratio eta/s for an equilibrated system of nucleons and…

Nuclear Theory · Physics 2014-11-20 Subrata Pal

The shear viscosity of an interacting pion gas is studied using the Kubo formalism as a microscopic description of thermal systems close to global equilibrium. We implement the skeleton expansion in order to approximate the retarded…

High Energy Physics - Phenomenology · Physics 2012-09-05 Robert Lang , Norbert Kaiser , Wolfram Weise

One of the hallmark properties of fluids is their shear viscosity which is, among other things, responsible for parabolic flow profiles through narrow channels. In recent years, there has been a growing number of observations of said flow…

Strongly Correlated Electrons · Physics 2024-08-02 Kitinan Pongsangangan , Pedro Cosme , Emanuele Di Salvo , Lars Fritz

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

Ultrarelativistic heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) are thought to have produced a state of matter called the Quark-Gluon-Plasma, characterized by a very small shear viscosity to entropy density ratio…

Nuclear Theory · Physics 2010-04-21 Nasser Demir , Steffen A. Bass

The leading order contribution to the shear and bulk viscosities, \eta and \zeta, of a gluon plasma in perturbative QCD includes the gg -> gg (22) process, gg <-> ggg (23) process and multiple scattering processes known as the…

High Energy Physics - Phenomenology · Physics 2015-03-19 Jiunn-Wei Chen , Jian Deng , Hui Dong , Qun Wang

Shear viscosity (eta) of QCD in the hadronic phase is computed by the coupled Boltzmann equations of pions and nucleons in low temperatures and low baryon number densities. The eta to entropy density ratio eta/s maps out the nuclear…

High Energy Physics - Phenomenology · Physics 2008-11-26 Jiunn-Wei Chen , Yen-Han Li , Yen-Fu Liu , Eiji Nakano

The temperature and density dependence of the relaxation times, thermal conductivity, shear viscosity and bulk viscosity for a hot and dense gas consisting of pions, kaons and nucleons have been evaluated in the kinetic theory approach. The…

Substantial collective flow is observed in collisions between large nuclei at high energy, and the data are well-reproduced by perfect fluid dynamics. In a separate development, calculation of the dimensionless ratio of shear viscosity…

Nuclear Theory · Physics 2013-08-01 Joseph I. Kapusta

The velocity dispersion-size relation ($\sigma_{\rm v}\sim R^{\beta}$) is a crucial indicator of the dynamic properties of interstellar gas, where the slope is considered as $\beta \sim 0.5$. Recent observations reveal a steep velocity…

Astrophysics of Galaxies · Physics 2025-05-14 Yi-Heng Xie , Guang-Xing Li

Second-order dissipative hydrodynamic equations for each component of a multi-component system are derived using the entropy principle. Comparison of the solutions with kinetic transport results demonstrates validity of the obtained…

High Energy Physics - Theory · Physics 2015-06-05 Andrej El , Ioannis Bouras , Christian Wesp , Zhe Xu , Carsten Greiner

The analytical Chapman-Enskog formula for calculating the shear viscosity $\eta$ of a relativistic ideal gas, such as a massless quark-gluon plasma, has consistently demonstrated good agreement with the numerical results obtained using the…

Nuclear Theory · Physics 2024-10-22 Noah M. MacKay

We have evaluated the shear viscosity of pion gas taking into account its scattering with the low mass resonances, $\sigma$ and $\rho$ during propagation in the medium. The thermal width (or collisional rate) of the pions is calculated from…

Nuclear Theory · Physics 2014-04-08 Sabyasachi Ghosh , Gastão Krein , Sourav Sarkar