Related papers: A note on background independence in $\text{AdS}_3…

The Coulomb branch of the N = 4 super-Yang-Mills theory is described by a D3-brane in the bulk of AdS_5 x S^5. We show that boundary conditions on this D3-brane preserve integrability of the AdS string. For that matter we construct…

String backgrounds of the form $\mathbb{M}_3 \times {\cal M}_7$ where $\mathbb{M}_3$ denotes $3$-dimensional Minkowski space while ${\cal M}_7$ is a $7$-dimensional G$_2$-manifold, are characterised by the property that the world-sheet…

String on $AdS_3\times S^3\times T^4$ backgrounds are known to be classically integrable in the presence of a mixture of Ramond-Ramond and Neveu-Schwarz-Neveu-Schwarz fluxes. It is expected that this results in the existence of a…

Double-trace deformations of the AdS/CFT duality result in a new perturbation expansion for string theory, based on a non-local worldsheet. We discuss some aspects of the deformation in the low energy gravity approximation, where it appears…

This thesis is devoted to the study of geometric aspects of black holes and integrable structures in string theory. In the first part, symmetries of the horizon and its bulk extension will be investigated. We investigate the horizon…

We revisit the fermionic string theory on $AdS_3\times \mathcal{N}$ with $k=1$, and its single-trace $T\bar T$ deformation, with a focus on the $(2,2)$ superstring on (deformed) $AdS_3\times \mathbb{T}^3$. In a certain limit, it is dual to…

We analyze the Coulomb branch of Matrix string theory in the presence of NS5-branes. If we regard the components of U(1) gauge fields as the dualized longitudinal coordinates, we obtain the symmetric product of AdS_3 x S^3 x R^4 as the…

The worldsheet string theory dual to free 4d ${\cal N}=4$ super Yang-Mills theory was recently proposed in arXiv:2104.08263. It is described by a free field sigma model on the twistor space of ${\rm AdS}_5\times {\rm S}^5$, and is a direct…

A class of background independent membrane field theories are studied, and several properties are discovered which suggest that they may play a role in a background independent form of M theory. The bulk kinematics of these theories are…

We continue the study of heterotic non-Abelian BPS-saturated flux tubes (strings). Previously, such solutions were obtained in U(N) gauge theories: N=2 supersymmetric QCD deformed by superpotential terms \mu A^2 breaking N=2 supersymmetry…

We investigate the possibility that stringy nonperturbative effects appear as holes in the world-sheet. We focus on the case of Dirichlet string theory, which we argue should be formulated differently than in previous work, and we find that…

In this note, we describe how the study of backgrounds for general quantum systems can be formulated in terms of the representation theory of abstract $C^*$ algebras. We illustrate our general framework through two example systems:…

Using the path integral approach, we discuss the correlation functions of the $SL(2,\bfC)/SU(2)$ WZW model, which corresponds to the string theory on the Euclidean $AdS_3$. We obtain the two- and three-point functions for generic primary…

The AdS/CFT correspondence of elementary string theory has been recently suggested as a ``microscopic'' approach to QCD string theory in various dimensions. We use the microscopic theory to show that the ultraviolet regime on the string…

We present evidence for the factorization of the world-sheet path integrals for 2d conformal field theories on the disk into bulk and boundary contributions. This factorization is then used to reinterpret a shift in closed string…

String theory on AdS_3 x S^3 is studied in the hybrid formulation. We give a detailed description of the PSL(2|2) supergroup WZW model that underlies the background with pure NS-NS flux, and determine the BRST-cohomology corresponding to…

Spin Matrix theory (SMT) limits provide a way to capture the dynamics of the AdS/CFT correspondence near BPS bounds. On the string theory side, these limits result in non-relativistic sigma models that can be interpreted as novel…

We construct a string theory in three-dimensional anti-de Sitter space-time that is independent of the boundary metric. It is a topologically twisted theory of quantum gravity. We study string theories with an asymptotic N=2 superconformal…

We study a modified bosonic string theory that has a pressureless ``dust'' field on the string worldsheet. The dust is a real scalar field with unit gradient which breaks conformal invariance. Hamiltonian analysis reveals a time…

The symmetric orbifold of $\mathbb{T}^4$ is exactly dual to string theory on $\mathrm{AdS}_3\times \mathrm{S}^3 \times \mathbb{T}^4$ with minimal ($k=1$) NS-NS flux. In this paper we study the perturbation of the symmetric orbifold that is…