We study the shear mode in the gauge/gravity correspondence at finite temperature. First, we confirm the general formula for the shear viscosity in an arbitrary background metric which includes a black hole in the fifth dimension. We then derive a general formula for the shear mode relaxation time which appears in the theory of relativistic dissipative fluid dynamics; it agrees with known expressions in the limit of conformal fields. These results may be useful in relativistic viscous fluid descriptions of high energy nuclear collisions at RHIC and LHC.
In this paper we calculate the ratio of transverse shear viscosity to entropy density for the general anisotropic black brane in Horava-Lifshitz gravity. There is a well-known conjecture that states this ratio should be larger than $\frac{1}{4π}$. The ratio of shear viscosity to entropy density is proportional to the inverse square coupling of quantum thermal field theory,$\frac{η}{s} \sim \frac{1}{λ^2 }$. Especially in QFT with gravity dual the stronger coupling means the shear viscosity per entropy density gets closer to the lower bound of $\frac{1}{4π}$. The KSS bound preserves in the aniso…
In this paper we explore the correspondence between four-dimensional Born-Infeld theory and five-dimensional classical gravity. The Born-Infeld theory side corresponds to the low energy effective theory for open strings ending on coincident D3-branes in a (slowly varying) background Kalb-Ramond field, including all higher-derivative corrections. On the gravity side one has the gravitational (closed string) description of D3-branes in the same background Kalb-Ramond field and the correspondence is thus a consequence of the open/closed string duality. According to the correspondence the gravity …
We study a geometrical representation of the quantum information metric in the gauge/gravity correspondence. We consider the quantum information metric that measures the distance between the ground states of two theories on the field theory side, one of which is obtained by perturbing the other. We show that the information metric is represented by a back reaction to the volume of a codimension-2 surface on the gravity side if the unperturbed field theory possesses the Poincare symmetry.
Gravity/Non-Commutative Yang-Mills Correspondence and Doubletons
本文讨论了非对易Yang-Mills理论的引力对偶描述，在对易极限下，该引力对偶描述约化为AdS_{5} x S_{5}的引力对偶描述.结果发现，在这种对偶引力描述中，除非取交换极限，否则双重态不解耦。在AdS_{5}空间中的二重态的退耦意味着对偶规范理论具有SU（N）规范对称性。我们的结果意味着这种引力描述与非对易U（N）规范理论是对偶的。这与非对易U（N）规范理论中U（1）和SU（N）规范对称性不可分离的观点是一致的。
Wilson loops in (p+1)-dimensional Yang-Mills theories using gravity/gauge theory correspondence
利用引力/规范理论对应，计算了（p+1）维Yang-Mills理论强耦合等离子体中类时和类光威尔逊圈的期望值.由类时威尔逊圈得到了偶极以任意速度0<v 1穿过等离子体时的速度相关夸克-反夸克势<1 and also obtain expressions for the screening lengths. When the velocity v-->，威尔逊圈变为类光，并得到了强耦合等离子体中喷流猝灭参数的形式。
On the Gauge/Gravity Correspondence and the Open/Closed String Duality
在这篇文章中，我们审查的规范/重力对应的有效性在超对称和非超对称弦模型的条件。我们首先回顾一下IIB型理论在轨道折叠C^2/Z_2和C^3/（Z_2 x Z_2）上发生了什么，在这些轨道上，这种对应非常好。在这些情况下，通过对D3膜之间的相互作用进行一个完整的弦计算，已经表明这种对应起作用的事实是开/闭对偶和缺乏阈值校正的结果。然后，我们回顾了0型理论的建设，其orbifolds和orientifolds具有开放和封闭弦快子的光谱，对于这样的模型，我们研究了规范/引力对应的有效性，得出的结论是，这不是一个特殊的超对称理论，但它也可能适用于非超对称模型。同样在这些情况下，当它起作用时，它又是开/闭弦对偶和消失阈值修正的结果。
We studied the canonical structure of 2D $F(R)$ gravity. Its equivalence with Jackiw-Teitelboim gravity is demonstrated when no matter presents. Then, due to AdS$_2$/CFT$_1$ correspondence, such $F(R)$ gravity is equivalent to the Sachdev-Ye--Kitaev models. The singular $D\to 2$ limit of $F(R)$ gravity is also studied. It is shown that in such a limit AdS$_2$/CFT$_1$ correspondence is not realized.
We investigate $η/s$ in linear scalar fields modified Gauss-Bonnet theory that breaks translation invariance. We first calculate $η/s$ both analytically and numerically and show its relationship with temperature in log-log plot. Our results show that $η/s\sim T^2$ at low temperatures. The causality is also considered in this work. We then find that causality violation still happens in the presence of the linear scalar field and we suggest there is a Gauss-Bonnet coupling dependent lower limit for the effective mass of the graviton. If the effective mass of the graviton is big enough, then ther…
We construct a new toy model of the holographic principle, named as holographic qubit threads model, which is an enlightening step towards the issue of spacetime emergence ("it from qubit"). More specifically, we propose for the first time that each bit thread in a locking bit thread configuration is in a "qubit" state, i.e., the quantum superposition state of two orthogonal states. Using this thread/state correspondence, we can construct the explicit expressions for the SS states corresponding to a set of bulk extremal surfaces in the surface/state correspondence, and nicely characterize thei…
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. In this paper we establish this relation in Einstein gravity with general minimally-coupled matter, and also in theories with an additional non-minimally coupled scalar field. We consider two examples for explicit demonstrations.
In this work, a correspondence between black hole solutions of conformal and massive theories of gravity is found. It is seen that this correspondence imposes some constraints on parameters of these theories. What is more, a relation between the mass of black holes and the parameters of massive gravity is found. Indeed, the acceptable ranges of massive gravity parameters ($c_{1}$\ and $c_{2}$) are found. It is shown that by considering the positive mass of black holes, some ranges of $c_{1}$\ and $c_{2}$ are acceptable.
