Einstein-Yang-Mills AdS Black Brane Solution in Massive Gravity and Viscosity Bound

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 boundary and regularity on the horizon conditions.Comment: 10 pages, accepted by the European Physical Journal

Holographic Aspects of a Higher Curvature Massive Gravity

We study the holographic dual of a massive gravity with Gauss-Bonnet and cubic quasi-topological higher curvature terms. Firstly, we find the energy-momentum two-point function of the 4-dimensional boundary theory where the massive term breaks the conformal symmetry as expected. An $a$-theorem is introduced based on the null energy condition. Then we focus on a black brane solution in this background and derive the ratio of shear viscosity to entropy density for the dual theory. It is worth mentioning that the concept of viscosity as a transport coefficient is obscure in a nontranslational invariant theory as in our case. So although we use the Green-Kubo's formula to derive it, we rather call it the rate of entropy production per the Planckian time due to a strain. Results smoothly cover the massless limit.Comment: v2: 20 pages, typo corrected, references added; v3: section 2.2 revised; v4: section 2.2 modified, viscosity formula revised, 2 figs added, references added; v5: 23 pages, a sign mistake in eq. (74) fixed (results modified), eq. (34) modified, one fig added, refs added, to appear in EPJ

Knowledge-based potentials in protein fold recognition

An accurate potential function is essential for protein folding problem and structure prediction. Two different types of potential energy functions are currently in use. The first type is based on the law of physics and second type is referred to as statistical potentials or knowledge based potentials.  In the latter type, the energy function is extracted from statistical analysis of experimental data of known protein structures. By increasing the amount of three dimensional protein structures, this approach is growing rapidly.There are various forms of knowledge based potentials depending on how statistics are calculated and how proteins are modeled. In this review, we explain how the knowledge based potentials are extracted by using known protein structures and briefly compare many of the potentials in theory

The effect of three matters on KSS bound

Our goal in this manuscript is to introduce black brane solutions in AdS 4-dimensional (4D) Einstein-Gauss-Bonnet-Yang-Mills theory in presence of string cloud and quintessence. Shear viscosity to entropy density ratio is computed via fluid-gravity duality, as a transport coefficient for this model.Comment: 10 pages, no figur

Holographic Aspects of Non-minimal RμανβF(a)μαF(a)νβR_{\mu \alpha \nu \beta } F^{(a)\mu \alpha } F^{(a)\nu \beta } AdS Black Brane

In this paper, we study the holographic dual to an asymptotically anti-de Sitter black brane in an Einstein-Yang-Mills model with a non-minimal coupling between the Riemann and Yang-Mills fields. First, we construct a planar black hole solution of this model up to the first order of the non-minimal coupling of the Yang-Mills field with the Riemann-Christoffel tensor, denoted as $q_2$. Then, we calculate the color non-abelian direct current (DC) conductivity and the ratio of shear viscosity to entropy density for this solution. Our result for the shear viscosity $\eta$ to entropy density $s$ ratio saturates the Kovtun, Son, and Starinets (KSS) bound, which is proportional to $\frac{1}{4 \pi}$. However, our result for the conductivity is new up to the first order of $q_2$.Comment: 11 Pages, no figure, typo corrected, references added, minor modifications, accepted for publication in CQ