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相关论文: The Effect of Bulk Dimension in the presence of St…

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The Einstein AdS black brane with a cloud of strings background in context of massive gravity is introduced. There is a momentum dissipation on the boundary because of graviton mass on the bulk. The ratio of shear viscosity to entropy…

高能物理 - 理论 · 物理学 2019-09-23 Mehdi Sadeghi , Hadi Ranjbari

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…

高能物理 - 理论 · 物理学 2021-09-20 Mehdi Sadeghi

We introduce the Einstein-Yang-Mills AdS black brane solution in context of massive gravity. The ratio of shear viscosity to entropy density is calculated for this solution. This value violates the KSS bound if we apply the Dirichlet…

高能物理 - 理论 · 物理学 2018-11-01 Mehdi Sadeghi

In this paper we introduce the black brane solutions in AdS space in 4-dimensional (4D) Einstein-Gauss-Bonnet-Yang-Mills theory in the presence of string cloud and quintessence. Shear viscosity to entropy density ratio is computed via…

高能物理 - 理论 · 物理学 2023-12-20 Mehdi Sadeghi

We investigate the Einstein-Hilbert black brane solution in four-dimensional Anti-de Sitter (AdS) spacetime supplemented by a quadratic Ricci scalar term $q L^2 R^2$, where $q$ is a dimensionless coupling constant and $L$ is the AdS radius.…

高能物理 - 理论 · 物理学 2026-02-06 Razieh Golmoradifard , Mehdi Sadeghi , Behrooz Malekolkalami

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 for…

高能物理 - 理论 · 物理学 2018-10-29 Mehdi Sadeghi

The shear viscosity bound violation in Einstein gravity for anisotropic black branes is discussed, with the aim of constraining the deviation of the shear viscosity-entropy density ratio from the shear viscosity bound using causality and…

高能物理 - 理论 · 物理学 2016-02-02 Xian-Hui Ge

We argue that the Kovtun--Son--Starinets (KSS) lower bound on the viscosity to entropy density ratio holds in fluid systems but is violated in solid materials with a non-zero shear elastic modulus. We construct explicit examples of this by…

高能物理 - 理论 · 物理学 2017-01-13 Lasma Alberte , Matteo Baggioli , Oriol Pujolas

We consider asymptotically-AdS $n$-dimensional black brane solutions in a theory of gravity coupled to a set of $N$ $p$-form field strengths, in which the field strengths carry magnetic charges. For appropriately chosen charges, the metrics…

高能物理 - 理论 · 物理学 2017-02-01 Hai-Shan Liu , H. Lu , C. N. Pope

Motivated by the vast string landscape, we consider the shear viscosity to entropy density ratio in conformal field theories dual to Einstein gravity with curvature square corrections. After field redefinitions these theories reduce to…

高能物理 - 理论 · 物理学 2010-04-06 Mauro Brigante , Hong Liu , Robert C. Myers , Stephen Shenker , Sho Yaida

In this paper, we explore a modified black brane within AdS spacetime, characterized by the Lagrangian density $\frac{1}{q} \text{arcsin}(qR)-2\Lambda$. Due to the absence of an analytic solution, we approach the Einstein equations using a…

高能物理 - 理论 · 物理学 2024-10-29 Mehdi Sadeghi

A black brane solution to a Gauss-Bonnet massive gravity is introduced. In the context of AdS/CFT correspondence, the viscosity to entropy ratio is found by the Green-Kubo formula. The result indicates violation of the well-known KSS bound…

高能物理 - 理论 · 物理学 2016-01-27 Mehdi Sadeghi , Shahrokh Parvizi

The ratio of shear viscosity to entropy density $\eta/s$ of any material in nature has been conjectured to have a lower bound of $1/4\pi$, the famous KSS bound. We examine string theory models for evidence in favour of and against this…

高能物理 - 理论 · 物理学 2009-11-18 Aninda Sinha , Robert C. Myers

We analyze the spacetime metric associated with a black string surrounded by a cloud of strings and an anisotropic fluid of quintessence in cylindrically symmetric AdS spacetime. We solve Einstein's equation to obtain the explicit form of…

广义相对论与量子宇宙学 · 物理学 2025-02-10 Maria de Lourdes Deglmann , Leonardo G. Barbosa , Celso de Camargo Barros

In this paper we consider a metric with hyperscaling violation on black brane background. In this background we calculate the ratio of shear viscosity to entropy density with hydrodynamics information. The calculation of this quantity lead…

高能物理 - 理论 · 物理学 2015-06-19 Jafar Sadeghi , Ali Asadi

We construct anisotropic black brane solutions and analyse the behaviour of some of their metric perturbations. These solutions correspond to field theory duals in which rotational symmetry is broken due an externally applied, spatially…

高能物理 - 理论 · 物理学 2022-11-21 Sachin Jain , Rickmoy Samanta , Sandip P. Trivedi

We calculate the ratio of shear viscosity to entropy density for charged black branes in third order Lovelock theory. For chargeless black branes, the result turns out to be consistent with the prediction made in $\rm arXiv:0808.3498[\rm…

高能物理 - 理论 · 物理学 2009-11-17 Xian-Hui Ge , Sang-Jin Sin , Shao-Feng Wu , Guo-Hong Yang

A model of a cloud formed by massive strings is used as a source of Bianchi type II. We assumed that the expansion $(\theta)$ in the model is proportional to the shear $(\sigma)$. To get exact solution, we have considered the equation of…

综合物理 · 物理学 2015-06-12 Hassan Amirhashchi

Regular black strings solutions associated to a dynamical Friedmann-Robertson-Walker braneworld are obtained as a particular case of a regular bulk metric, in the context of a variable brane tension. By analyzing the 5D Kretschmann…

高能物理 - 理论 · 物理学 2014-09-05 D. Bazeia , J. M. Hoff da Silva , Roldao da Rocha

Recently it was established in Einstein-Maxwell-Dilaton gravity that the KSS viscosity/entropy ratio associated with AdS planar black holes can be viewed as the boundary dual to the generalized Smarr relation of the black holes in the bulk.…

高能物理 - 理论 · 物理学 2016-05-11 Hai-Shan Liu
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