On semiclassical four‐point correlators in AdS5 × S5

Following the recent advances in the holographic calculation of n‐point correlation functions with two “heavy” (with large quantum numbers) states at strong coupling, we extend these findings by computing specific contributions to four‐point correlators of four heavy BMN operators in �� = 4 supersymmetric Yang–Mills theory.     

On the algebraic curves for circular and folded strings in AdS5×S5

There have been recent advances in the construction of algebraic curves for certain classes of string solutions in the context of the AdS/CFT correspondence. In this paper we obtain the Lax operators and associated spectral curves for circular and folded string solutions in AdS ${}_5\times S^5$. In addition, we provide an original approach for the reconstruction of string solutions in S³ from their corresponding curves.     

p‐wave superconductors in dilaton gravity

In this paper, we study peculiar properties of p‐wave superconductors in dilaton gravity. The scale invariance of the bulk geometry is effectively broken due to the existence of a dilaton. By coupling the dilaton to the non‐Abelian gauge field, i.e., ‐1/4 e^{‐β Φ} F^a_μνF^aμν, we find that the dissipative conductivity of the normal phase decreases and approaches zero at the zero frequency as β increases. Intuitively, the system behaves more and more like an insulator. When the hairy solution is turned on, the system crosses a critical point to the superconducting phase. We find that the critical chemical potential decreases with the increasing of β and the maximum height of the conductivity is suppressed gradually which are consistent with our intuition for insulator/supercondutor transition.     

Note on surface growth approach for bulk reconstruction

In this paper, we show using several examples that the bulk geometry of asymptotically AdS\begin{document}$ _3 $\end{document}spacetimes can be effectively reconstructed using an intuitive and visual method called the surface growth scheme. This new approach for bulk reconstruction was originally proposed in a recent paper, along with its explicit realization using the one-shot entanglement distillation tensor network and the surface/state correspondence. In this paper, we directly analyze the growth of the bulk minimal surfaces to implement this scheme. Our study provides further support for the surface growth approach in entanglement wedge reconstruction.     

Logarithmic corrections to entropy and AdS/CFT

We calculate the correction to the Bekenstein-Hawking entropy formula for five-dimensional AdS-Schwarzschild black holes due to thermodynamic fluctuations. The result is then compared with the boundary gauge theory entropy corrections via AdS/CFT correspondence.     

Holographic p-wave superfluid with Weyl corrections

In this work,we study the effects of the Weyl corrections on the p-wave superfluid phase transition in terms of an EinsteinMaxwell theory coupled to a complex vector field.In the probe limit,it is observed that the phase structure is significantly modified owing to the presence of the higher order Weyl corrections.The latter,in general,facilitates the emergence of the superfluid phase as the condensate increases with the Weyl coupling measured byγ.Moreover,several features about the phase structure of the holographic superfluid are carefully investigated.In a specific region,the phase transition from the normal phase to the superfluid phase is identified to be the first order,instead of being the second order,as in the cases for many holographic superconductors.By carrying out a numerical scan of model parameters,the boundary dividing these two types of transitions is located and shown to be rather sensitive to the strength of Weyl coupling.Also,a feature known as"Cave of Winds",associated with the emergence of a second superfluid phase,is observed for specific choices of model parameters.However,it becomes less prominent and eventually disappears asγincreases.Furthermore,for temperature in the vicinity of the critical one for vanishing superfluid velocity,denoted by T0,the supercurrent is found to be independent of the Weyl coupling.The calculated ratio,of the condensate with vanishing superfluid velocity to that with maximal superfluid velocity,is in good agreement with that predicted by Ginzburg-Landau theory.While compared with the impact on the phase structure owing to the higher curvature corrections,the findings in our present study demonstrate entirely different characteristics.Further implications are discussed.     

R~4 corrections to holographic Schwinger effect

We consider R4 corrections to the holographic Schwinger effect in an AdS black hole background and a confining D3-brane background. The potential between a test particle pair are performed for both backgrounds. We find there is no potential barrier in the critical electric field, which means that the system becomes catastrophically unstable. It is shown that for both backgrounds, increasing the inverse 't Hooft coupling parameter 1/λ enhances the Schwinger effect. We also discuss the possible relation between the Schwinger effect and the viscosity-entropy ratioη/s in strong coupling.     

Note on the holographic c‐function

We discuss the holographic c‐function and describe an algorithm for the practical computation of the changing central charge in arbitrary RG‐flows. The conclusions are drawn from studying a particular example, which is worked out in detail. The renormalisation procedure of hep‐th/0112150 necessary to obtain the central charge is reviewed.     

A Note on Black Holes in Asymptotically Lifshitz Spacetime

We investigate several aspects of exact black hole solutions in asymptotically Lifshitz spacetime. Firstly,we calculate the tidal forces and find that in the near horizon region of such black hole backgrounds, the tidal forces diverge in the near extremal limit. Secondly, we evaluate the Wilson loops in both extremal and finite temperature cases. Finally, we obtain the corresponding shear viscosity and square of the sound speed and find that the ratio of shear viscosity to entropy density takes the universal value 1/4π in arbitrary dimensions while the square of the speed of sound saturates the conjectured bound 1/3 in five dimensions.     

Holographic fermions with running chemical potential and dipole coupling

We explore the properties of the holographic fermions in extremal R-charged black hole background with a running chemical potential, as well as the dipole coupling between fermions and the gauge field in the bulk. We find that although the running chemical potential effect the location of the Fermi surface, it does not change the type of fermions. We also study the onset of the Fermi gap and the gap effected by running chemical potential and the dipole coupling. The spectral function in the limit ω→0$\omega \to 0$ and the existence of the Fermi liquid are also investigated. The running chemical potential and the dipole coupling altogether can make a non-Fermi liquid become the Landau–Fermi type.     

[Review] An Introduction to AdS/CFT Correspondence forPhenomenologists

We give a brief introduction to the AdS/CFT correspondence and its application to QCD physics, especially its application in the study of quark-gluon-plasma(QGP) formed in the relativistic heavy ion collision (RHIC). This review is based on the talksgiven in several schools and programs for the phenomenologists working on nuclear physicsand particle physics.     

A Note on Black Holes in Asymptotically Lifshitz Spacetime

We investigate several aspects of exact black hole solutions in asymptotically Lifshitz spacetime. Firstly, we calculate the tidal forces and find that in the near horizon region of such black hole backgrounds, the tidal forces diverge in the near extremal limit. Secondly, we evaluate the Wilson loops in both extremal and finite temperature cases. Finally, we obtain the corresponding shear viscosity and square of the sound speed and find that the ratio of shear viscosity to entropy density takes the universal value 1/4π in arbitrary dimensions while the square of the speed of sound saturates the conjectured bound 1/3 in five dimensions.     

一类新的Stückelberg全息超导模型

本文研究了含Stückelberg机理的黑洞全息超导模型. 通过选取标量场新的高阶修正形式, 建立了新的Stückelberg黑洞全息超导模型. 通过研究模型参数对标量场凝聚的影响, 发现了当模型参数大于临界值时, 高阶修正可以引起一阶相变. 同时本文还考查了反作用对临界值的影响.     

Properties of CFTs dual to charged BTZ black hole

We study properties of strongly coupled CFT's with non-zero background electric charge in 1+1$1+1$ dimensions by studying the dual gravity theory—which is a charged BTZ black hole. Correlators of operators dual to scalars, gauge fields and fermions are studied at both T=0$T=0$ and T≠0$T\ne 0$. In the T=0$T=0$ case we are also able to compare with analytical results based on AdS₂${\mathit{AdS}}_2$ and find reasonable agreement. In particular the correlation between log periodicity and the presence of finite spectral density of gapless modes is seen. The real part of the conductivity (given by the current–current correlator) also vanishes as ω→0$\omega \to 0$ as expected. The fermion Green's function shows quasiparticle peaks with approximately linear dispersion but the detailed structure is neither Fermi liquid nor Luttinger liquid and bears some similarity to a “Fermi–Luttinger” liquid. This is expected since there is a background charge and the theory is not Lorentz or scale invariant. A boundary action that produces the observed non-Luttinger liquid like behavior (k  -independent non-analyticity at ω=0$\omega =0$) in the Green's function is discussed.     

String theory as a theory of quantum gravity: a status report

We review the status of string theory as a quantum theory of gravity. Our emphasis is on outstanding questions and remaining challenges rather then on well-established results and successes.