alpha'-corrections from O(d,d) symmetry

• Linus Wulff

Room: Computational Foundry Building When the tree-level closed string effective action is reduced from D to D-d dimensions an O(d,d) symmetry appears. I will discuss how a certain necessary condition for this O(d,d) symmetry to be present can be used to determine the complete action at order alpha'^2 and all terms involving less than six fields at order alpha'^3 in the NSNS sector.

JT gravity & NATD

• Anayeli Ramirez

Room: Computational Foundry Building I will discuss the geometries obtained by performing super non-Abelian T-duality of the Principal Chiral Model on OSp(1|2). Inspired by what happens in the purely bosonic case the dual supergeometry is written as the supersymmetric version of AdS2 fibered over what we interpret as the superspace equivalent of the standard bosonic line. I will also discuss that in a suitable limit, the action of the three-dimensional dual model reduces to a Jackiw-Teitelboim-like (super)gravity action in two dimensions, both in the bosonic and the supersymmetric cases.

Principal chiral model in arbitrary magnetic field: exact solution in planar limit

• Vladimir Kazakov

Room: Computational Foundry Building The two-dimensional Principal Chiral Model (PCM) has been considered since long as an instructive example of a QFT bearing certain similarities with QCD: asymptotic freedom, dimensional transmutation with a physical mass spectrum and a non-trivial 't Hooft's large N limit. In addition, it is an integrable QFT, with the known physical S-matrix. In our 1994 paper with V.Fateev and P.Wiegmann, we found not only the exact but also explicit solution of the vacuum energy of SU(N)xSU(N) PCM in the 't Hooft limit in the presence of specific, albeit arbitrary strong, "magnetic" field (the chemical potential of density of physical particles). The shape of this field repeated the Perron-Frobenius (PF) mode on the su(N) Dynkin diagram. I will present our recent work with E.Sobko and K.Zarembo (arxiv:2312.04801) where we explicitly solved the Bethe equation for the magnetic field of arbitrary shape. We also studied this solution in the case of small deviations of the magnetic field from the PF mode and found a perfect correspondence with the known perturbative and strong coupling results. I will also mention our results of our previous work: the 1/N expansion of the energy and a possible interpretation of PCF as a 2+1-dimensional noncritical string theory, where the role of the 3rd dimension is played by Dynkin diagram.

Integrability and deformations of Thirring models

• Alexis Roa Aguirre

Room: Computational Foundry Building In this talk, I will discuss some important aspects of integrability and deformations of the Grassmannian and Bosonic Thirring models. In the first part of the talk, I will concern with the presence of integrable defects, the generalization to coupled Thirring models, and their Backlund transformations. In the second part, I will focus on the deformations of the Thirring models, and the construction of coupled sineGordon-sineGordon models via S-duality.

Lattice discretization of 2d integrable quantum field theories from 4d Chern-Simons theory

• Jun-ichi Sakamoto

Room: Computational Foundry Building The relationship between 2d integrable field theory and 2d integrable lattice models is discussed in the framework of 4d Chern-Simons theory. The 2d integrable field theory is realized by coupling the 4d theory to several 2d surface ordered defects, each defect is then discretized into a 1d defect. We show that the resulting 1d defects are dualized to Wilson lines, and the lattice of discretized defects realizes an integrable lattice model. Our discretization procedure works systematically for a wide class of integrable models (including trigonometric and elliptic models). This is based on a work [hep-th/2309.14412] with Meer Ashwinkumar and Masahito Yamazaki.

Dualities of Integrable Field Theories from 4d Chern-Simons Theory

• Meer Ashwinkumar

Room: Computational Foundry Building In this talk, I will explore dualities of integrable field theories through the lens of four-dimensional Chern-Simons theory, where these dualities can be viewed as dualisations of order surface defects. I will begin by discussing a type of duality that emerges from the discretisation-induced dualities of surface defects. Following this, I will delve into the anomaly-inflow mechanism for surface defects, which leads us to a second form of duality. This type of duality arises from the bosonisation of free-fermion surface defects, leading us to bosonisation dualities between generalisations of the massless Thirring model and coupled Wess-Zumino-Witten (WZW) models. This talk is based on work [hep-th/2309.14412] with Jun-ichi Sakamoto and Masahito Yamazaki.

Integrable defects in N=4 SYM

• Marius de Leeuw

Room: Computational Foundry Building In this talk I will discuss the classification of integrable conformal defects in N=4 SYM theory for which the scalar fields pick up a non-trivial vacuum expectation value. Defects of this form correspond to Dirichlet boundary conditions that have a pole at the defect. These set-ups typically appear on the field theory side of probe brane set-ups in the AdS/CFT correspondence. I will discuss the properties of the different possible fuzzy spheres that can appear and present the corresponding Matrix Product States. I will also comment on the quantum field theoretic framework such as the mass matrix and propagators.

Quantum supermembranes and AdS/CFT

• Arkady Tseytlin

Room: Computational Foundry Building We will review some recent work on semiclassical quantization of 11d supermembrane. We will demonstrate how quantum corrections to supermembrane partition function are consistent with AdS/CFT in the context of ABJM theory and how they represent particular higher loop terms in string loop expansion.

An integrable deformation of the heterotic string

• David Osten

Room: Computational Foundry Building A novel classically integrable model is proposed. It is a deformation of a two-dimensional principal chiral or WZW model, embedded into a heterotic σ-model. This is inspired by the bosonic part of the heterotic σ-model and its recent Hamiltonian formulation in terms of O(d,d+n)-generalised geometry. Classical integrability is shown by construction of a Lax pair and a classical r-matrix. I briefly discuss the non-trivial non-deformation limit and the deformed backgrounds as solutions of heterotic supergravity.

Coordinate Bethe Ansatz for N=2 SCFTs

• Deniz Bozkurt

Room: Computational Foundry Building The study of the spectral problem of planar N=2 SCFTs and their corresponding spin chains has been an inauspicious problem. In this talk I want to present a novel approach to the coordinate Bethe Ansatz which allowed the computation of the three-magnon wave function (paper to appear) for the spin chains that capture the spectral problem of the marginally deformed Z_2 orbifold of N=4 SYM in planar limit. The novel idea is the introduction of contact terms which incorporate the dynamical structure of the spin chains and it can be generalized to n-body problem and also to more general orbifolds.

Scattering on effective strings and membranes

• Fiona Seibold

Room: Computational Foundry Building The Nambu-Goto string action can be related to an integrable deformation of a free theory. The scattering of excitations on the two-dimensional worldsheet of the string is then very simple, given by a pure phase. In this talk I will consider the setup of a membrane in flat space. I will analyse the dynamics of excitations on the three-dimensional worldvolume of the membrane, and also compactify the theory on a circle. I will present the perturbative S-matrix, compare with the Nambu-Goto case, and discuss the integrability of the model.

Evidence for a four-dimensional N = 1 integrable quiver in massive type IIA supergravity

• José Manuel Penín

Room: Computational Foundry Building We examine a newly discovered parametric family of backgrounds in massive type IIA supergravity that contains a warped AdS5 factor. This family is the dual gravity description of four-dimensional quivers with N=1 supersymmetry. We are interested in the status of classical integrability in these theories, and we show that there exists a single choice of solutions that is special, while all other choices lead to nonintegrable quivers and chaotic string motion. By focusing on this special choice, we provide strong suggestive evidence for the integrability of the dual field theory based on analytic studies and extensive numerical analysis.

QCD form factors from large N chiral algebras

• Roland Bittleston

Room: Computational Foundry Building The collinear singularities of form factors in certain self-dual QCDs determine an abstract chiral algebra. In this talk I will realize an example concretely as the large N limit of an algebra of operators living on a 2d holomorphic surface defect. The construction goes via twisted holography for the type I topological string on a Calabi-Yau 5-fold related to twistor space. I will explain how this realization can be exploited to compute QCD form factors in flat space, and helicity amplitudes on a range of self-dual backgrounds. This is joint work with Kevin Costello and Keyou Zeng.

Large charge and integrability

• Susanne Reffert

Room: Computational Foundry Building The large-charge expansion has in the last few years proven to be a powerful tool for analytically accessing strongly-coupled CFTs. When working in a sector of fixed and large global charge, it is often possible to write an EFT for this sector as an expansion controlled by inverse powers of the large charge. I will introduce the large-charge method and discuss its relationship and interactions with integrability.

Integrability from Chern-Simons Theory on Twistor Space

• Lewis Cole

Room: Computational Foundry Building Insights into the origin of integrability are provided by two 4d gauge theoretic descriptions -- 4d Chern-Simons theory and self-dual Yang-Mills theory. Recently, both of these 4d models have been realised as children of a parent theory: 6d holomorphic Chern-Simons theory on twistor space. After a review of these topics, I will discuss our work extending this formalism.

Landscapes of integrable long-range spin chains

• Rob Klabbers

Room: Computational Foundry Building I will give an overview of the recent advances in understanding long-range integrable spin chains, focusing on a general construction that yields (q-)deformations of known models based on a solution of a Yang-Baxter equation. Even for the simplest sl_2-case, this construction generates two, mostly disconnected landscapes of models, with many intriguing properties. I will highlight those I believe to be most interesting to the IDD audience. based on https://arxiv.org/abs/2306.13066 and arxiv:2405.xxxxx (expected to appear before May 15th), both with Jules Lamers.

A generalized 4d Chern-Simons theory

• David Schmidtt

Room: Computational Foundry Building We formally introduce a deformation of the 4d Chern-Simons theory, whose path integral takes the canonical symplectic form required by the non-Abelian localization method. The methodology is based on the Beasley-Witten construction applied to conventional 3d Chern-Simons theory. This opens the possibility for studying integrable field theories using geometric tools.

Poster Session Room: Computational Foundry Building

A 3d topological-holomorphic integrable field theory from 2-groups

• Hank Chen

Room: Computational Foundry Building The 2d Wess-Zumino-Witten CFT is an integrable field theory that is known to host infinitely many conserved currents that obey the affine Kac-Moody algebra. This talk is based on the joint work https://arxiv.org/abs/2405.18625 with J. Liniado, where we introduced a 3d integrable field theory which can be thought of as a topological-holomorphic analogue of the 2d WZW CFT. A detailed analysis of its conserved chiral higher currents reveals the structure of a differential graded analogue of the 2-Kac-Moody algebra akin to Hennion-Faonte-Kapranov, and their higher holonomies have interesting geometric properties.

Kinematics and odd crossing in mixed flux AdS3/CFT2

• Bogdan Stefański, jr.

Room: Computational Foundry Building

Generalized cosets in exceptional geometry

• Yuho Sakatani

Room: Computational Foundry Building Various extensions of Poisson-Lie T-duality have been studied recently. For the duality group O(D,D), the most general extension is known as the generalized T-duality of generalized cosets (extending dressing cosets). In this talk, considering the U-duality group E_{n(n)}, I will explain a construction of the generalized cosets in exceptional geometry, which we call exceptional generalized cosets. I will then discuss the generalized U-dualities among different exceptional generalized cosets. I will also explain how the exceptional generalized cosets can be used to study consistent truncations of maximal supergravities. This talk is based on works with Falk Hassler, arXiv:2311.12095 and ongoing work.

Classical deformations of Celestial Chiral Algebras

• Simon Heuveline

Room: Computational Foundry Building This talk is based on arXiv:2305.09451, arXiv:2403.18011 and work in progress. I will discuss several deformations of gravitational celestial chiral algebras which are closely related to $w_{1+\infty}$ and give bulk interpretations of the respective deformations. Some of these deformations arise naturally from a backreaction in self-dual Einstein gravity analogous to part of the recent top-down construction of Costello, Paquette and Sharma and I will highlight similarities and differences.

Symmetric Space Sine-Gordon Theories

• Marc Magro

Room: Computational Foundry Building Some aspects of Symmetric Space Sine-Gordon Theories will be reviewed: their definitions, their properties and the peculiarity of their integrability structure.

Yangians and R-matrices for cotangent Lie algebras

• Raschid Abedin

Room: Computational Foundry Building This talk is about a canonical quantization of Lie bialgebra structures on the loop algebra with coefficients in the semi-direct product of a simple complex Lie algebra and its dual. The quantization gives rise to twists of the natural analog of the Yangian for this algebra. The Yangian admits a meromorphic R-matrix, which relates its coproduct with a meromorphic coproduct. The construction of the Yangian is motivated by the fact that its representations can be interpreted as perturbative line operators in a 4d holomorphic topological gauge theory. This talk is based on the following joint work with Wenjun Niu: arXiv:2405.19906.

Integrability in twist-deformed SYM

• Stijn van Tongeren

Room: Computational Foundry Building Maximally supersymmetric Yang-Mills theory (SYM) in four dimensions is famously integrable, and AdS/CFT dual to the AdS5 superstring. The latter string admits a varied landscape of integrable Yang-Baxter deformations, which are conjectured to correspond to certain noncommutative deformations of SYM on the field theory side. Recently a large number of these twist-noncommutative deformations of SYM were explicitly constructed, making it possible to investigate their integrability, and ultimately perform precision tests of holography in this novel setting. I will consider deformations based on Cartan generators, where restricting to R symmetry gives the famous real beta deformation of SYM, but adding in Lorentz generators we get interesting new models. The simplest of these is an angular dipole deformation of SYM, which admits a class of gauge invariant operators whose two-point functions can be determined from a twisted integrable spin chain, at least as long as we restrict ourselves to the spacetime plane not touched by the deformation. This twisted structure precisely matches the one known for the conjectured dual string, providing a strong check of the conjectured duality. I will then discuss how integrable spin chains may be realized when considering operators at general positions in angular dipole deformed SYM, and comment on attempts to extrapolate this story to the analogous fully spacetime-noncommutative Lorentz deformation.

Scattering on self-dual black holes

• Tim Adamo

Room: Computational Foundry Building Tree-level graviton scattering amplitudes provide an on-shell model for wave-wave scattering in general relativity, but computing them with traditional perturbative methods is hard due to the non-polynomial nature of the Einstein-Hilbert action. This is particularly true for the study of graviton scattering in curved spacetimes, like black holes, which remains an extremely difficult problem. In this talk, I will discuss a simplification of this problem: graviton scattering on a self-dual black hole (in particular, a self-dual Taub-NUT space). This lets us bring powerful integrability methods to bear while still exhibiting the non-linear and non-perturbative hallmarks of 'real world' graviton scattering on black holes.

Rotating strings and anomalous dimensions in TTbar deformation

• Meseret Asrat

Room: Computational Foundry Building We consider certain rigidly rotating closed string configurations in an asymptotically non-AdS string background. The string background is a deformation of AdS_3 × M_7 with NSNS two-from B field. It interpolates between AdS_3 and asymptotically linear dilaton IR × S^1 × IR spacetime (times the internal compact manifold M_7). In the long string sector the deformation is dual to a single trace TTbar deformed symmetric product theory. We compute the quantity E −J for certain rotating folded and cusped closed strings where E is the energy and J is the angular momentum of the strings. In the two dimensional CFT dual to string theory on AdS_3 (times M_7) it gives the anomalous dimensions of certain twist two and higher operators. We discuss the structure of (large angular momentum J expansion) of E − J and comment on what it measures away from the CFT along the deformation in the coupling space. We also discuss the closely related cusp anomalous dimension of a light-like Wilson loop. We also give semiclassical results for the energy of certain non-spinning pulsating strings. The talk is based on my recent paper: arXiv:2404.16601[hep-th].

Supergravity backgrounds from λ-deformations

• Georgios Itsios

Room: Computational Foundry Building In this talk, I will discuss the construction of two supersymmetric solutions of type-II supergravity based on the λ-deformed σ-models for SL(2,R) and SU(2). In the absence of deformation, they describe near-horizon limits of NS1 and NS5 brane intersections and both are 1/2-supersymmetric. When the deformation is turned on, supersymmetry breaks by half and both backgrounds preserve 8 supercharges.

The Hagedorn temperature for integrable gauge theories

• Joseph Minahan

Room: Computational Foundry Building I discuss recent progress in computing the Hagedorn temperature at strong coupling for N=4 SYM and ABJM theory.