Scattering equations, generating functions and all massless five point tree amplitudes

We argue that one does not need to know the explicit solutions of the scattering equations in order to evaluate a given amplitude. We consider the most general quantity consistent with SL(2,C) invariance that can appear in an amplitude that admits a scattering equation description. This quantity depends on all cross ratios that can be formed from n points and we evaluate it for the first non-trivial case of n=5. The combinatorial nature of the problem is captured through the construction of an appropriate generating function that depends on five variables.Comment: 11 pages; published version, clarifications added and minor typos correcte

Next to subleading soft-graviton theorem in arbitrary dimensions

We study the soft graviton theorem recently proposed by Cachazo and Strominger. We employ the Cachazo, He and Yuan formalism to show that the next to subleading order soft factor for gravity is universal at tree level in arbitrary dimensions.Comment: 14 pages; v2: references added, typos correcte

Exact solutions for N-magnon scattering

Giant magnon solutions play an important role in various aspects of the AdS/CFT correspondence. We apply the dressing method to construct an explicit formula for scattering states of an arbitrary number N of magnons on R x S^3. The solution can be written in Hirota form and in terms of determinants of N x N matrices. Such a representation may prove useful for the construction of an effective particle Hamiltonian describing magnon dynamics.Comment: 19 pages, 1 figur

Space-like minimal surfaces in AdS x S

We present a four parameter family of classical string solutions in AdS_3 x S^3, which end along a light-like tetragon at the boundary of AdS_3 and carry angular momentum along two cycles on the sphere. The string surfaces are space-like and their projections on AdS_3 and on S^3 have constant mean curvature. The construction is based on the Pohlmeyer reduction of the related sigma model. After embedding in AdS_5 x S^5, we calculate the regularized area and analyze conserved charges. Comments on possible relations to scattering amplitudes are presented. We also sketch time-like versions of our solutions.Comment: v3: 30 pages, reference added, minor change

Dressed Wilson loops on S-2

archiveprefix: arXiv primaryclass: hep-th reportnumber: HU-EP-11-19 slaccitation: %%CITATION = ARXIV:1104.3746;%%archiveprefix: arXiv primaryclass: hep-th reportnumber: HU-EP-11-19 slaccitation: %%CITATION = ARXIV:1104.3746;%%CK has been supported by Deutsche Forschungsgemeinschaft via SFB 647. DY was supported by FNU through grant number 272-08-0329

Coordinate representation of particle dynamics in AdS and in generic static spacetimes

We discuss the quantum dynamics of a particle in static curved spacetimes in a coordinate representation. The scheme is based on the analysis of the squared energy operator E^2, which is quadratic in momenta and contains a scalar curvature term. Our main emphasis is on AdS spaces, where this term is fixed by the isometry group. As a byproduct the isometry generators are constructed and the energy spectrum is reproduced. In the massless case the conformal symmetry is realized as well. We show the equivalence between this quantization and the covariant quantization, based on the Klein-Gordon type equation in AdS. We further demonstrate that the two quantization methods in an arbitrary (N+1)-dimensional static spacetime are equivalent to each other if the scalar curvature terms both in the operator E^2 and in the Klein-Gordon type equation have the same coefficient equal to (N-1)/(4N).Comment: 14 pages, no figures, typos correcte