scholarly journals Impact of the chromo-electromagnetic field fluctuations on transport coefficients of heavy quarks and shear viscosity to entropy density ratio of quark-gluon plasma

2019 ◽  
Vol 986 ◽  
pp. 48-59
Author(s):  
Ashik Ikbal Sheikh ◽  
Zubayer Ahammed
Keyword(s):  
Electromagnetic Field ◽  
Shear Viscosity ◽  
Quark Gluon Plasma ◽  
Transport Coefficients ◽  
Density Ratio ◽  
Gluon Plasma ◽  
Heavy Quarks ◽  
Entropy Density ◽  
Field Fluctuations

scholarly journals Backreaction effects due to matter coupled higher derivative gravity

2015 ◽  
Vol 30 (16) ◽  
pp. 1550065 ◽  
Author(s):  
Lata Kh Joshi ◽  
P. Ramadevi
Keyword(s):  
Shear Viscosity ◽  
Quark Gluon Plasma ◽  
Transport Coefficients ◽  
Gluon Plasma ◽  
Entropy Density ◽  
Flow Measurements ◽  
Strongly Coupled ◽  
Higher Derivative ◽  
Scalar Matter ◽  
Dimensional Spacetime

AdS-hydrodynamics has proven to be a useful tool for obtaining transport coefficients observed in the collective flow of strongly coupled fluids like quark gluon plasma (QGP). Particularly, the ratio of shear viscosity to entropy density η/s obtained from elliptic flow measurements can be matched with the computation done in the dual gravity theory. The experimentally observed temperature dependence of η/s requires the study of scalar matter coupled AdS gravity including higher derivative curvature corrections. We obtain the backreaction to the metric for such a matter coupled AdS gravity in D-dimensional spacetime due to the higher derivative curvature corrections. Then, we present the backreaction corrections to shear viscosity η and entropy density s.

scholarly journals Drag force on heavy quarks and spatial string tension

2018 ◽  
Vol 33 (06) ◽  
pp. 1850041 ◽  
Author(s):  
Oleg Andreev
Keyword(s):  
String Duality ◽  
Drag Coefficient ◽  
Heavy Quark ◽  
Quark Gluon Plasma ◽  
Diffusion Coefficients ◽  
Transport Coefficients ◽  
Gluon Plasma ◽  
String Tension ◽  
Heavy Quarks ◽  
Strongly Coupled

Heavy quark transport coefficients in a strongly coupled Quark–Gluon Plasma can be evaluated using a gauge/string duality and lattice QCD. Via this duality, one can argue that for low momenta the drag coefficient for heavy quarks is proportional to the spatial string tension. Such a tension is well-studied on the lattice that allows one to straightforwardly make non-perturbative estimates of the heavy quark diffusion coefficients near the critical point. The obtained results are consistent with those in the literature.

scholarly journals Exploring the Partonic Phase at Finite Chemical Potential in and out-of Equilibrium

Particles ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 178-192 ◽  
Author(s):  
O. Soloveva ◽  
P. Moreau ◽  
L. Oliva ◽  
V. Voronyuk ◽  
V. Kireyeu ◽  
...  
Keyword(s):  
Cross Sections ◽  
Chemical Potential ◽  
Transport Coefficients ◽  
Gluon Plasma ◽  
Entropy Density ◽  
Baryon Chemical Potential ◽  
Equilibrium Study ◽  
200 Gev ◽  
Quasiparticle Model ◽  
Scattering Cross Sections

We study the influence of the baryon chemical potential μ B on the properties of the Quark–Gluon–Plasma (QGP) in and out-of equilibrium. The description of the QGP in equilibrium is based on the effective propagators and couplings from the Dynamical QuasiParticle Model (DQPM) that is matched to reproduce the equation-of-state of the partonic system above the deconfinement temperature T c from lattice Quantum Chromodynamics (QCD). We study the transport coefficients such as the ratio of shear viscosity η and bulk viscosity ζ over entropy density s, i.e., η / s and ζ / s in the ( T , μ ) plane and compare to other model results available at μ B = 0 . The out-of equilibrium study of the QGP is performed within the Parton–Hadron–String Dynamics (PHSD) transport approach extended in the partonic sector by explicitly calculating the total and differential partonic scattering cross sections based on the DQPM and the evaluated at actual temperature T and baryon chemical potential μ B in each individual space-time cell where partonic scattering takes place. The traces of their μ B dependences are investigated in different observables for symmetric Au + Au and asymmetric Cu + Au collisions such as rapidity and m T -distributions and directed and elliptic flow coefficients v 1 , v 2 in the energy range 7.7 GeV ≤ s N N ≤ 200 GeV.

scholarly journals Shear viscosity to entropy density ratio of Hagedorn states

2020 ◽  
Vol 102 (3) ◽  
Author(s):  
Jan Rais ◽  
Kai Gallmeister ◽  
Carsten Greiner
Keyword(s):  
Shear Viscosity ◽  
Density Ratio ◽  
Entropy Density

scholarly journals Causality of black holes in 4-dimensional Einstein–Gauss–Bonnet–Maxwell theory

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
Xian-Hui Ge ◽  
Sang-Jin Sin
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Shear Viscosity ◽  
Upper Bound ◽  
Causal Structure ◽  
Density Ratio ◽  
Entropy Density ◽  
Coupling Constant ◽  
Maxwell Theory ◽  
Black Hole Solutions

Abstract We study charged black hole solutions in 4-dimensional (4D) Einstein–Gauss–Bonnet–Maxwell theory to the linearized perturbation level. We first compute the shear viscosity to entropy density ratio. We then demonstrate how bulk causal structure analysis imposes an upper bound on the Gauss–Bonnet coupling constant in the AdS space. Causality constrains the value of Gauss–Bonnet coupling constant $$\alpha _{GB}$$αGB to be bounded by $$\alpha _{GB}\le 0$$αGB≤0 as $$D\rightarrow 4$$D→4.

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