Spectral Flow in AdS(3)/CFT(2)

We study the spectral flowed sectors of the H3 WZW model in the context of the holographic duality between type IIB string theory in AdS(3)x S^3 x T^4 with NSNS flux and the symmetric product orbifold of T^4. We construct explicitly the physical vertex operators in the flowed sectors that belong to short representations of the superalgebra, thus completing the bulk-to-boundary dictionary for 1/2 BPS states. We perform a partial calculation of the string three-point functions of these operators. A complete calculation would require the three-point couplings of non-extremal flowed operators in the H3 WZW model, which are at present unavailable. In the unflowed sector, perfect agreement has recently been found between the bulk and boundary three-point functions of 1/2 BPS operators. Assuming that this agreement persists in the flowed sectors, we determine certain unknown three-point couplings in the H3 WZW model in terms of three-point couplings of affine descendants in the SU(2) WZW model.Comment: 50 pages, 2 figure

FZZ Scattering

We study the duality between the two dimensional black hole and the sine-Liouville conformal field theories via exact operator quantization of a classical scattering problem. The ideas are first illustrated in Liouville theory, which is dual to itself under the interchange of the Liouville parameter b by 1/b. In both cases, a classical scattering problem does not determine uniquely the quantum reflection coefficient. The latter is only fixed by assuming that the dual scattering problem has the same reflection coefficient. We also discuss the relation of this approach to the method that exploits the parafermionic symmetry of the model to compute the reflection coefficient.Comment: 19 pages, JHEP style. v2: Minor changes in the proposed field of sine-Liouville type, new section discussing the relation with parafermionic symmetry, references adde

c < 1 String from Two Dimensional Black Holes

We study a topological string description of the c < 1 non-critical string whose matter part is defined by the time-like linear dilaton CFT. We show that the topologically twisted N=2 SL(2,R)/U(1) model (or supersymmetric 2D black hole) is equivalent to the c < 1 non-critical string compactified at a specific radius by comparing their physical spectra and correlation functions. We examine another equivalent description in the topological Landau-Ginzburg model and check that it reproduces the same scattering amplitudes. We also discuss its matrix model dual description.Comment: 36 pages, harvmac; acknowledgements, comments and references adde

Notes on S-Matrix of Non-critical N=2 String

In this paper we discuss the scattering S-matrix of non-critical N=2 string at tree level. First we consider the \hat{c}<1 string defined by combining the N=2 time-like linear dilaton SCFT with the N=2 Liouville theory. We compute three particle scattering amplitudes explicitly and find that they are actually vanishing. We also find an evidence that this is true for higher amplitudes. Next we analyze another \hat{c}<1 string obtained from the N=2 time-like Liouville theory, which is closely related to the N=2 minimal string. In this case, we find a non-trivial expression for the three point functions. When we consider only chiral primaries, the amplitudes are very similar to those in the (1,n) non-critical bosonic string.Comment: 27 pages, harvmac, section 5 modified: a relation to (1,n) non-critical bosonic string adde