Alday-Maldacena duality and AdS Plateau problem

Eikonal Approach to N=4 SYM Regge Amplitudes in the AdS/CFT Correspondence

The high-energy behavior of N=4 SYM elastic amplitudes at strong coupling is studied by means of the AdS/CFT correspondence. We consider the eikonal method proposed by Janik and one of the authors, where the relevant minimal surface is a "generalized helicoid" in hyperbolic space ("Euclidean AdS_5"), from which the physical amplitude is obtained after an appropriate analytic continuation. We then compare our results with those obtained, using a minimal surface in AdS_5 momentum space, by Alday and Maldacena for gluon-gluon scattering, and by Barnes and Vaman for quark-quark scattering ("Alday-…

Massive quark scattering at strong coupling from AdS/CFT

We extend the analysis of Alday and Maldacena for obtaining gluon scattering amplitudes at strong coupling to include external massive quark states. Our quarks are actually the N=2 hypermultiplets which arise when D7-brane probes are included in the AdS_5 x S^5 geometry. We work in the quenched approximation, treating the N=2 matter multiplets as external sources coupled to the N=4 SYM fields. We first derive appropriate massive-particle boundary conditions for the string scattering worldsheets. We then find an exact worldsheet which corresponds to the scattering of two massive quarks and two …

Regge behavior of gluon scattering amplitudes in N=4 SYM theory

It is shown that the four-gluon scattering amplitude for N=4 supersymmetric Yang-Mills theory in the planar limit can be written, in both the weak- and strong-coupling limits, as a reggeized amplitude, with a parent trajectory and an infinite number of daughter trajectories. This result relies crucially on the fact that the leading IR-divergence and the finite log^2(s/t)-dependent piece of the amplitude are characterized by the same function for all values of the coupling, as conjectured by Bern, Dixon, and Smirnov, and proved by Alday and Maldacena in the strong-coupling limit. We use the Ald…

Comments on gluon 6-point scattering amplitudes in N=4 SYM at strong coupling

We use the AdS/CFT prescription of Alday and Maldacena \cite{am} to analyze gluon 6-point scattering amplitudes at strong coupling in ${\cal N}=4$ SYM. By cutting and gluing we obtain AdS 6-point amplitudes that contain extra boundary conditions and come close to matching the field theory results. We interpret them as parts of the field theory amplitudes, containing only certain diagrams. We also analyze the collinear limits of 6- and 5-point amplitudes and discuss the results.

On spacelike and timelike minimal surfaces in $AdS_n$

We discuss timelike and spacelike minimal surfaces in $AdS_n$ using a Pohlmeyer type reduction. The differential equations for the reduced system are derived in a parallel treatment of both type of surfaces, with emphasis on their characteristic differences. In the timelike case we find a formulation corresponding to a complete gauge fixing of the torsion. In the spacelike case we derive three sets of equations, related to different parameterizations enforced by the Lorentzian signature of the metric in normal space. On the basis of these equations, we prove that there are no flat spacelike mi…

Series Solution and Minimal Surfaces in AdS

According to the Alday-Maldacena program the strong coupling limit of Super Yang-Mills scattering amplitudes is given by minimal area surfaces in AdS spacetime with a boundary consisting of a momentum space polygon. The string equations in AdS systematically reduce to coupled Toda type equations whose Euclidean classical solutions are then of direct relevance. While in the simplest case of AdS_3 exact solutions were known from earlier studies of the sinh-Gordon equation, there exist at present no similar exact forms for the generalized Toda equations related to AdS_d with d>=4. In this paper w…

Minimal area surfaces dual to Wilson loops and the Mathieu equation

The AdS/CFT correspondence relates Wilson loops in N=4 SYM to minimal area surfaces in $AdS_5\times S^5$ space. Recently, a new approach to study minimal area surfaces in $AdS_3 \subset AdS_5$ was discussed based on a Schroedinger equation with a periodic potential determined by the Schwarzian derivative of the shape of the Wilson loop. Here we use the Mathieu equation, a standard example of a periodic potential, to obtain a class of Wilson loops such that the area of the dual minimal area surface can be computed analytically in terms of eigenvalues of such equation. As opposed to previous exa…

具有瞬子以及拓扑变化极小面的胶子散射振幅

Gluon scattering amplitudes with instantons and minimal surfaces with topology change

本文研究${\cal N}=4$超对称Yang-Mills理论中瞬子对强耦合大$N$下胶子散射振幅的影响，发现瞬子D-brane导致极小面拓扑变化，并在瞬子尺寸模量$ρ$大于${\cal O}(\sqrtλ/E)$时使振幅指数增强。

6d Dual Conformal Symmetry and Minimal Volumes in AdS

The S-matrix of a theory often exhibits symmetries which are not manifest from the viewpoint of its Lagrangian. For instance, powerful constraints on scattering amplitudes are imposed by the dual conformal symmetry of planar 4d $\mathcal{N}=4$ super Yang-Mills theory and the ABJM theory. Motivated by this, we investigate the consequences of dual conformal symmetry in six dimensions, which may provide useful insight into the worldvolume theory of M5-branes (if it enjoys such a symmetry). We find that 6d dual conformal symmetry uniquely fixes the integrand of the one-loop 4-point amplitude, and …

强耦合下的振幅作为超凯勒标量

Amplitudes at strong coupling as hyperkähler scalars

本文发现AdS$_3$中极小曲面振幅的余函数满足可积微分方程，并通过Y-系统在运动学空间上定义伪超凯勒结构，将其作为该几何的凯勒标量，为强耦合下非微扰振幅的猜想提供了新视角。