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We study the viscosity and thermodynamic properties of QGP at RHIC by employing the recently extracted equilibrium distribution functions from two hot QCD equations of state of $O(g^5)$ and $O(g^6\ln(1/g))$ respectively. After obtaining the…

Nuclear Theory · Physics 2011-07-19 Vinod Chandra , V. Ravishankar

Shear viscosity measures the amount of internal friction in a simple fluid. In kinetic theory shear viscosity is related to momentum transport by quasi-particles, and the uncertainty relation implies that the ratio of shear viscosity eta to…

Fluid Dynamics · Physics 2010-01-15 Thomas Schaefer

We calculate the shear viscosity over entropy density ratio $\eta/s$ in Yang--Mills theory from the Kubo formula using an exact diagrammatic representation in terms of full propagators and vertices using gluon spectral functions as external…

High Energy Physics - Phenomenology · Physics 2015-09-16 Nicolai Christiansen , Michael Haas , Jan M. Pawlowski , Nils Strodthoff

We study the conductivity and shear viscosity tensors of a strongly coupled N=4 super-Yang-Mills plasma which is kept anisotropic by a theta parameter that depends linearly on one of the spatial dimensions. Its holographic dual is given by…

High Energy Physics - Theory · Physics 2013-05-30 Anton Rebhan , Dominik Steineder

We study the ratio of the entropy to the total energy in conformal field theories at finite temperature. For the free field realizations of N=4 super Yang-Mills theory in D=4 and the (2,0) tensor multiplet in D=6, the ratio is bounded from…

High Energy Physics - Theory · Physics 2007-05-23 George Siopsis

The first law for entanglement entropy in CFT in an odd-dimensional asymptotically AdS black hole is studied by using the AdS/CFT duality. The entropy of CFT considered here is due to the entanglement between two subsystems separated by the…

High Energy Physics - Theory · Physics 2021-07-14 Akihiro Ishibashi , Kengo Maeda

We investigate $\eta/s$ in linear scalar fields modified Gauss-Bonnet theory that breaks translation invariance. We first calculate $\eta/s$ both analytically and numerically and show its relationship with temperature in log-log plot. Our…

High Energy Physics - Theory · Physics 2016-09-28 Yi-Li Wang , Xian-Hui Ge

We present the complete family of solutions of 3D gravity (Lambda<0) with two asymptotically AdS exterior regions. The solutions are constructed from data at the two boundaries, which correspond to two independent and arbitrary stress…

High Energy Physics - Theory · Physics 2015-06-19 Gautam Mandal , Ritam Sinha , Nilakash Sorokhaibam

By studying classes of supersymmetric solutions of D=11 supergravity with AdS_5 factors, we determine some properties of the dual four-dimensional N=1 superconformal field theories. For some explicit solutions we calculate the central…

High Energy Physics - Theory · Physics 2010-02-03 Jerome P. Gauntlett , Eoin O Colgain , Oscar Varela

A computation of the quotient of shear viscosity to entropy density, or KSS number $\eta/s$ is performed, in the non-relativistic and classical regime, first in Chiral Perturbation Theory, and then in the $SO(g+1)/SO(g)$ Non-Linear Sigma…

High Energy Physics - Theory · Physics 2008-11-26 Antonio Dobado , Felipe J. Llanes-Estrada

We study hydrodynamic fluctuations in a non-relativistic fluid. We show that in three dimensions fluctuations lead to a minimum in the shear viscosity to entropy density ratio $\eta/s$ as a function of the temperature. The minimum provides…

Quantum Gases · Physics 2013-03-14 Clifford Chafin , Thomas Schaefer

We explore the influence of a temperature-dependent shear viscosity over entropy density ratio $\eta/s$ on the azimuthal anisotropies v_2 and v_4 of hadrons at various rapidities. We find that in Au+Au collisions at full RHIC energy,…

Nuclear Theory · Physics 2014-11-13 Etele Molnar , Hannu Holopainen , Pasi Huovinen , Harri Niemi

We investigate the low-temperature behavior of the ratio between the shear viscosity \eta and the entropy density s in the unitary Fermi gas by using a model based on the zero-temperature spectra of both bosonic collective modes and…

Quantum Gases · Physics 2011-11-08 Luca Salasnich , Flavio Toigo

We consider the shear viscosity of a system of quarks and its ratio to the entropy density above the critical temperature for deconfinement. Both quantities are derived and computed for different modeling of the quark self-energy, also…

High Energy Physics - Phenomenology · Physics 2008-11-26 W. M. Alberico , S. Chiacchiera , H. Hansen , A. Molinari , M. Nardi

The shear viscosity $\eta$ for a dilute classical gas of hard-sphere particles is calculated by solving the Boltzmann kinetic equation in terms of the weakly absorbed plane waves. For the rare-collision regime, the viscosity $\eta$ as a…

Statistical Mechanics · Physics 2018-01-29 A. G. Magner , M. I. Gorenstein , U. V. Grygoriev

In heavy-ion collisions, quark-gluon plasma is likely to be produced with sizable initial pressure anisotropy, which may leave an imprint on electromagnetic observables. In order to model a strongly coupled anisotropic plasma, we use the…

High Energy Physics - Theory · Physics 2015-05-28 Anton Rebhan , Dominik Steineder

We determine analytically the dependence of the approach to thermal equilibrium of strongly coupled plasmas on the breaking of scale invariance. The theories we consider are the holographic duals to Einstein gravity coupled to a scalar with…

High Energy Physics - Theory · Physics 2016-02-17 Umut Gursoy , Matti Jarvinen , Giuseppe Policastro

We consider holographic duals of $2$-dimensional conformal field theories in the presence of a boundary, interface, defect and/or junction, referred to collectively as BCFTs. In general, the presence of a boundary reduces the $SO(2,2)$…

High Energy Physics - Theory · Physics 2015-06-18 John Estes

We consider an expanding boost-invariant plasma at strong coupling using the AdS/CFT correspondence for N=4 SYM. We determine the relaxation time in second order viscous hydrodynamics and find that it is around thirty times shorter than…

High Energy Physics - Theory · Physics 2008-11-26 Michal P. Heller , Romuald A. Janik

The shear viscosity to entropy density ratio, \eta /s, characterizes how perfect a fluid is. We calculate the leading order \eta /s of a gluon plasma in perturbation using the kinetic theory. The leading order contribution only involves the…

High Energy Physics - Phenomenology · Physics 2015-03-17 Jiunn-Wei Chen , Jian Deng , Hui Dong , Qun Wang