We study the boundary N = 2 Liouville theory based on the “modular bootstrap” approach. As fundamental conformal blocks we introduce the “extended characters” that are defined as the proper sums over… (More)

We study the type II superstring theory on the background R ×Xn, where Xn is a Calabi-Yau n-fold (2n + d = 10) with an isolated singularity, by making use of the holographically dual description… (More)

In this paper we discuss various aspects of non-compact models of CFT of the type: ∏NL j=1{N = 2 Liouville theory}j ⊗ ∏NM i=1{N = 2 minimal model}i and ∏NL j=1{SL(2;R)/U(1) supercoset}j⊗ ∏NM i=1 {N =… (More)

We study the type II string theories compactified on manifolds of G2 holonomy of the type (Calabi-Yau 3-fold×S)/Z2 where CY3 sectors realized by the Gepner models. We construct modular invariant… (More)

We investigate (super) string theory on AdS3 background based on an approach of free field realization. We demonstrate that this string theory can be reformulated as a string theory defined on a… (More)

We study propagation of D0-brane in two-dimensional Lorentzian black hole backgrounds by the method of boundary conformal field theory of SL(2,R)/U(1) supercoset at level k. Typically, such… (More)

Making use of the N = 2 Liouville theory and world-sheet techniques, we study the properties of D-branes wrapped around vanishing SUSY cycles of singular Calabi-Yau n-folds (n = 2, 3, 4). After… (More)

We study a class of non-geometric string vacua realized as completely soluble superconformal field theory (SCFT). These models are defined as ‘interpolating orbifolds’ of K3×S1 by the mirror… (More)

We construct modular invariant partition functions for strings propagating on noncompact manifolds of G2 holonomy. Unlike the compact case discussed by Shatashvili and Vafa partition functions do not… (More)

We study D-branes in SU(2) WZW model by means of the boundary state techniques. We realize the “fuzzy sphere” configuration of multiple D0-branes as the boundary state with the insertion of suitable… (More)