Gor Sarkissian

Symmetry breaking, permutation D-branes on group manifolds: boundary states and geometric description

We use the permutation symmetry between the product of several group man- ifolds in combination with orbifolds and T-duality to construct new classes of symmetry breaking branes on products of group manifolds. The resulting branes mix the submani- folds and break part of the diagonal chiral algebra of the theory. We perform a Langrangian analysis as well as a boundary CFT construction of these branes and find agreement be- tween the two methods.

Non-maximally symmetric D-branes on group manifold in the Lagrangian approach

Recently, Maldacena, Moore and Seiberg introduced non-maximally symmetric boundary states on group manifold using T-duality. In the work presented here we suggest simple description of these branes in terms of group elements. We show that T-dualization actually reduces to multiplication of conjugacy classes by the corresponding U(1) subgroups. Using this description we find the two-form trivializing the WZW three-form on the branes. SU(2) and SL(2,) examples are considered in details.

Defects in G/H coset, G/G topological field theory and discrete Fourier-Mukai transform

Abstract In this paper we construct defects in coset G / H theory. Canonical quantization of the gauged WZW model G / H with N defects on a cylinder and a strip is performed and the symplectomorphisms between the corresponding phase spaces and those of double Chern–Simons theory on an annulus and a disc with Wilson lines are established. Special attention to topological coset G / G has been paid. We prove that a G / G theory on a cylinder with N defects coincides with Chern–Simons theory on a torus times the time-line R with 2N Wilson lines. We have shown also that a G / G theory on a strip with N defects coincides with Chern–Simons theory on a sphere times the time-line R with 2 N + 4 Wilson lines. This particular example of topological field theory enables us to penetrate into a general picture of defects in semisimple 2D topological field theory. We conjecture that defects in this case described by a 2-category of matrices of vector spaces and that the action of defects on boundary states is given by the discrete Fourier–Mukai transform.

Generalised permutation branes on a product of cosets Gk1/H×Gk2/H

We study the modifications of the generalized permutation branes defined in hep-th/0509153, which are required to give rise to the non-factorizable branes on a product of cosets Gk1/H×Gk2/HGk1/H×Gk2/H. We find that for k1≠k2k1≠k2 there exists big variety of branes, which reduce to the usual permutation branes, when k1=k2k1=k2 and the permutation symmetry is restored.

On D-branes in the Nappi-Witten and GMM gauged WZW models

We construct D-branes in the Nappi-Witten (NW) and Guadagnini-Martellini-Mintchev (GMM) gauged WZW models. For the SL(2,) × SU(2)/U(1) × U(1) NW and SU(2) × SU(2)/U(1) GMM models we present thte explicit equations describing the D-brane hypersurfaces in their target spaces. In the latter case we show that the D-branes are classified according to the Cardy theorem. We also present the semiclassical mass computation and find its agreement with the CFT predictions.

On DBI action of the non-maximally symmetric D-branes on SU(2)

In this paper we study the non-maximally symmetric D-branes on the SU(2) group discussed in a previous article [11]. Using the two-form defined in [11] the DBI action on the branes is constructed. This action is checked for its agreement with CFT predictions. The geometry of the branes is analyzed in detail, and the singularities of branes covering the entire group are found.

Generalised permutation branes on a product of cosets

We study the modifications of the generalized permutation branes defined in hep-th/0509153, which are required to give rise to the non-factorizable branes on a product of cosets Gk1/H×Gk2/HGk1/H×Gk2/H. We find that for k1≠k2k1≠k2 there exists big variety of branes, which reduce to the usual permutation branes, when k1=k2k1=k2 and the permutation symmetry is restored.

On Cardy states in the (2,2,2,2) Gepner model

We study Cardy states in the (2,2,2,2)(2,2,2,2) Gepner model from both the algebraic and geometric vantage points. We present the full list of primaries of this model together with their characters. The effects of fixed point resolution are analyzed. Annulus partition functions between various Cardy states are calculated. Using the equivalent description in terms of the T4/Z4T4/Z4 orbifold, the corresponding geometric realization is partially found.

Generalised permutation branes on a product of cosets Gk1/H×Gk2/HGk1/H×Gk2/H

We study the modifications of the generalized permutation branes defined in hep-th/0509153, which are required to give rise to the non-factorizable branes on a product of cosets Gk1/H×Gk2/HGk1/H×Gk2/H. We find that for k1≠k2k1≠k2 there exists big variety of branes, which reduce to the usual permutation branes, when k1=k2k1=k2 and the permutation symmetry is restored.

On Cardy states in the (2,2,2,2)(2,2,2,2) Gepner model

We study Cardy states in the (2,2,2,2)(2,2,2,2) Gepner model from both the algebraic and geometric vantage points. We present the full list of primaries of this model together with their characters. The effects of fixed point resolution are analyzed. Annulus partition functions between various Cardy states are calculated. Using the equivalent description in terms of the T4/Z4T4/Z4 orbifold, the corresponding geometric realization is partially found.