scholarly journals Hydrodynamics in a black brane with hyperscaling violation metric background

2014 ◽  
Vol 92 (12) ◽  
pp. 1570-1572 ◽  
Author(s):  
J. Sadeghi ◽  
A. Asadi
Keyword(s):  
Shear Viscosity ◽  
Entropy Density ◽  
Point Of View ◽  
Black Brane ◽  
Hyperscaling Violation

In this paper we consider a metric with hyperscaling violation on a black brane background. In this background we calculate the ratio of shear viscosity to entropy density with hydrodynamics information. The calculation of this quantity leads us to a constraint on θ as 3 ≤ θ < 4, and θ ≤ 0. In that case we show that the quantity η/s is not dependent on hyperscaling violation parameter θ. Our results about ratio of shear viscosity to entropy density from the QCD point of view agree with other works in the literature as 1/4π.

scholarly journals The effect of bulk dimension in the presence of string cloud on viscosity bound

2020 ◽  
pp. 2050330
Author(s):  
Mehdi Sadeghi
Keyword(s):  
Shear Viscosity ◽  
Dirichlet Boundary ◽  
Massive Gravity ◽  
Entropy Density ◽  
Black Brane ◽  
Black Brane Solution ◽  
Brane Solution ◽  
Arbitrary Dimensions

In this paper, the Einstein AdS black brane solution in the presence of a string cloud in the context of d-dimensional massive gravity is introduced. The ratio of shear viscosity to entropy density for this solution violates the KSS bound by applying the Dirichlet boundary and regularity on the horizon conditions. Our result shows that this value is independent of string cloud in any arbitrary dimensions.

scholarly journals Black brane solution in Rastall AdS massive gravity and viscosity bound

2018 ◽  
Vol 33 (37) ◽  
pp. 1850220 ◽  
Author(s):  
Mehdi Sadeghi
Keyword(s):  
Shear Viscosity ◽  
Massive Gravity ◽  
Entropy Density ◽  
Black Brane ◽  
Black Brane Solution ◽  
Brane Solution

In this paper, we introduced the black brane solution in Rastall theory and in the context of massive gravity. The ratio of shear viscosity to entropy density is calculated for this solution. Our result shows that the KSS bound violates this theory.

scholarly journals AdS black brane solution surrounded by quintessence in massive gravity and KSS bound

2021 ◽  
pp. 2150202
Author(s):  
Mehdi Sadeghi
Keyword(s):  
Shear Viscosity ◽  
Dirichlet Boundary ◽  
Massive Gravity ◽  
Entropy Density ◽  
Regularity Conditions ◽  
Black Brane ◽  
Black Brane Solution ◽  
Brane Solution ◽  
Arbitrary Dimensions

In this paper, the Einstein AdS black brane solution in the presence of quintessence in context of massive gravity is introduced. The ratio of shear viscosity to entropy density for this solution violates the KSS bound by applying the Dirichlet boundary and regularity conditions on the horizon for [Formula: see text]. Our result shows that this value is independent of quintessence in any arbitrary dimensions.

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.

scholarly journals Proposed lower bound for the shear viscosity to entropy density ratio in some dense liquids

2009 ◽  
Vol 373 (10) ◽  
pp. 992-998 ◽  
Author(s):  
G.G.N. Angilella ◽  
N.H. March ◽  
F.M.D. Pellegrino ◽  
R. Pucci
Keyword(s):  
Lower Bound ◽  
Shear Viscosity ◽  
Density Ratio ◽  
Entropy Density

scholarly journals Analytical shear viscosity in hyperscaling violating black brane

2017 ◽  
Vol 773 ◽  
pp. 422-427 ◽  
Author(s):  
Xiao-Mei Kuang ◽  
Jian-Pin Wu
Keyword(s):  
Shear Viscosity ◽  
Black Brane
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