Related papers: Bi-$\eta$ and bi-$\lambda$ deformations of $\mathb…
We construct a new class of integrable $\sigma$-models based on current algebra theories for a general semisimple group $G$ by utilizing a left-right asymmetric gauging. Their action can be thought of as the all-loop effective action of two…
We analyse completely the BRST cohomology on local functionals for two dimensional sigma models coupled to abelian world sheet gauge fields, including effective bosonic D-string models described by Born-Infeld actions. In particular we…
We propose a two-dimensional superstring sigma model that defines a self-contained corner of heterotic string theory, whose second quantization is heterotic matrix string theory. This worldsheet theory arises from a BPS decoupling limit…
We study a string motion in the Lunin-Maldacena background, that is, the \beta-deformed AdS_5 \times \tilde{S}^5 background dual to a \beta-deformation of \mathcal{N} = 4 super Yang-Mills theory. For real \beta we construct a rotating and…
A brief review of problems, arising in the study of the beta-deformation, also known as "refinement", which appears as a central difficult element in a number of related modern subjects: beta \neq 1 is responsible for deviation from free…
Quantization of the geometric quasiconformal realizations of noncompact groups and supergroups leads directly to their minimal unitary representations (minreps). Using quasiconformal methods massless unitary supermultiplets of…
We find a nonsupersymmetric dilatonic deformation of $AdS_5$ geometry as an exact nonsingular solution of the type IIB supergravity. The dual gauge theory has a different Yang-Mills coupling in each of the two halves of the boundary…
We present the construction of the $\lambda$-deformation of $AdS_5\times S^5$ superstring from the four dimensional Chern-Simons-type gauge theory. The procedure is applicable to all the semi-symmetric coset models and generalizes the…
We consider a certain ${\cal N}=1$ supersymmetric, $SO(3)\times SO(3)$ invariant, subsector of the $\omega$-deformed family of $SO(8)$-gauged ${\cal N}=8$ four-dimensional supergravities. The theory contains two scalar fields and two…
On a supersymmetric sigma model the covariantly constant forms are related to the conserved currents that are generators of a super W-algebra extending the superconformal algebra. The existence of covariantly constant forms restricts the…
Thirty years ago Aragone and Deser showed that in three dimensions there exists a consistent model describing interaction for massless spin-2 and spin-5/2 fields. It was crucial that these fields lived in a flat Minkowski space and as a…
We study the relation between exactly marginal deformations in a large class of N=1 superconformal quiver gauge theories described by brane tilings and the degrees of freedom in the corresponding 5-brane systems. We show, with the help of…
We consider bosonic subsectors of the q-deformed AdS_5 x S^5 superstring action and study the classical integrable structure of anisotropic Landau-Lifshitz sigma models (LLSMs) derived by taking fast-moving limits. The subsectors are 1)…
We construct integrable deformations of the $\lambda$-type for asymmetrically gauged WZW models. This is achieved by a modification of the Sfetsos gauging procedure to account for a possible automorphism that is allowed in $G/G$ models. We…
We address the novel structures arising in quantum and string integrable theories, as well as construct methods to obtain them and provide further analysis. Specifically, we implement the automorphic symmetries on periodic lattice systems…
Fermionic extensions of generic 2d gravity theories obtained from the graded Poisson-Sigma model (gPSM) approach show a large degree of ambiguity. In addition, obstructions may reduce the allowed range of fields as given by the bosonic…
We construct heterotic string theories on spacetimes of the form R^{d-1,1} times N=2 linear dilaton, where d=6,4,2,0. There are two lines of supersymmetric theories descending from the two supersymmetric ten-dimensional heterotic theories.…
We investigate the worldsheet S matrix of string theory in $\eta$-deformed $AdS_5\times S^5$. By computing the six-point tree-level S matrix we explicitly show that there is no particle production at this level, as required by the classical…
An explicitly exact superconformal description is provided to some classes of Type II string theories in non constant RR backgrounds. This is done by applying the manifest (2,2) approach of Berkovits and Maldacena to Type II strings and by…
We construct supersymmetric deformations of general, locally supersymmetric, nonlinear sigma models in three spacetime dimensions, by extending the pure supergravity theory with a Chern-Simons term and gauging a subgroup of the sigma model…