Schedule for Talks

• Time: 09:40 - 10:30 | Speaker:  Martin Cederwall (Chalmers University of Technology, Sweden)
  Title: BV formulation of extended geometry [PDF]
  Abstract: I review the construction of BV fields and antifields in extended geometry from gradings of tensor hierarchy algebras. Special focus is on situations where the structure algebra and the extended space are infinite-dimensional.

[arXiv numbers of relevant papers: 2504.20873 (review), 2503.17779, 2402.04055, 2303.15391, 2112.08403, 2103.02476, 1908.08696, 1908.08695, 1804.04377, 1711.07694.]

• Time: 11:00 - 11:50 | Speaker: Yuho Sakatani (Kyoto Prefectural University of Medicine, Japan)
  Title: Extended geometry and generalized cosets [PDF]
  Abstract: After a brief review of the basics of extended geometry, I will introduce the concept of generalized cosets. Generalized cosets provide a systematic way to study consistent truncations in supergravity, and they also offer new insights into generalized dualities that go beyond the well-established T-duality and U-duality.
  
  

• Time: 14:00 - 14:50 | Speaker: Keith Glennon (OIST, Japan)
  Title: The E11-Inspired Approach to Gravity [N/A]
  Abstract: In this talk we will review the E11 inspired approach to Einstein’s gravity in 4D based on the Kac-Moody algebra A1+++. This generalises the pattern of Ehler’s and Geroch symmetry groups in general relativity. We will compare this with the E11 symmetries of the theory of strings and branes.
  
  

• Time: 15:00 - 15:50 | Speaker: Calvin Yi-Ren Chen (National Taiwan University, Taiwan)
  Title: Deformations of extremal black holes [PDF]
  Abstract: In this talk, I will re-examine a class of extremal charged black holes in AdS and study their EFT corrections. I will start by introducing static perturbations to the near-horizon geometry of extremal black holes. It turns out these generically suffer from singularities of various degrees. Particular deformations are marginal – they are not singular in GR, but even arbitrarily small EFT corrections seem to be able to make them singular. I will clarify that the apparent UV sensitivity does not lead to a breakdown of EFT, demonstrating this with a particular UV completion. If time permits, I will discuss a speculative bound on EFT coefficients. These are closely related to otherwise known bounds from causality and the swampland program, and would provide direct insight into UV completions to GR.
  
  

• Time: 16:20 - 16:45 | Speaker: Jeong-Hyuck Park (Sogang University, Korea)
  Title: Gravitational Core of Double Field Theory [PDF] 
  Abstract: Double Field Theory  has emerged as a comprehensive framework for gravity, presenting a testable and robust alternative to General Relativity, rooted in the O(D,D) symmetry principle of string theory.  This talk   aims to provide an accessible introduction to Double Field Theory, structured in a manner similar to traditional General Relativity courses. Key topics include doubled-yet-gauged coordinates, Riemannian versus non-Riemannian parametrisations of fundamental fields, covariant derivatives, curvatures, and the O(D,D)-symmetric augmentation of the Einstein field equation, identified as the unified field equation for the closed string massless sector. 
  [Talk is based on a review paper:  https://arxiv.org/abs/2505.10163.]
  
  

• Time: 16:45 - 17:10 | Speaker: Hun Jang (Sogang University, Korea)
  Title: Traversable wormhole for strings but not for particles [PDF]
  Abstract: In this talk, I will present a wormhole solution through which chiral strings can go while particles do not. The traversable wormhole is obtained by the string-vacuum 4D effective action consisting of the NS-NS-sector massless modes (metric, Kalb-Ramond field, and dilaton) within the framework of double field theory (DFT), without requiring any exotic DFT matter. This work implies that analysing wormhole traversability purely in terms of point-particle geodesics is insufficient if string theory truly works in nature. Notably, the traversing string solution appears to transcend the details of the wormhole geometry, suggesting the pregeometric nature of chiral strings. Nevertheless, it is the H-flux that enables the chiral string to traverse. Removing this flux would invalidate the traversability. Based on this result, it is conjectured that an ordinary string near a wormhole may split into chiral and antichiral modes to traverse it. After crossing, these modes could merge back into a single ordinary string.
  [Ref.: arXiv:2412.04128[hep-th]]

• Time: 09:40 - 10:30 | Speaker: Eric A. Bergshoeff (University of Groningen, Netherlands)
  Title: Non-relativistic p-brane limits of supergravity [PDF]
  Abstract: I will derive a  classification of  so-called non-relativistic p-brane limits of (the bosonic part) of supergravity in diverse dimensions that is based on the requirement that  they lead to a generalized Newton-Cartan gravity with a Newton potential that satisfies a Poisson equation in the directions transverse to the p-brane. I will discuss a few possible generalizations of this classification that makes contact with both (the bosonic part of) eleven-dimensional supergravity and ten-dimensional heterotic supergravity.
  
  

• Time: 11:00 - 11:50 | Speaker: Emil Have (Niels Bohr Institute, Denmark)
  Title: Boundary energy-momentum tensor for asymptotically flat spacetimes [PDF]
  Abstract: I will discuss the construction of a boundary energy-momentum tensor for asymptotically flat spacetimes. This involves rewriting Einstein's equations in a way that is covariant with respect to the Carrollian boundary geometry and turns part of the Einstein equations into Ward identities for the Carrollian energy-momentum tensor, providing new insights into a putative holographic description of flat spacetime in terms of a boundary Carrollian conformal field theory.
  [The talk is based on https://arxiv.org/abs/2505.05432.]
  
  

• Time: 14:00 - 14:50 | Speaker: Ziqi Yan (Nordita, Sweden)
  Title: A BPS road to holography [PDF]
  Abstract: I will discuss recent progress on the duality web that unifies BPS decoupling limits of string theory and M-theory, which play a central role in matrix theory and holography. I will show that non-Lorentzian geometry is an essential ingredient for understanding these BPS decoupling limits, leading to a new perspective on the AdS/CFT correspondence and its generalizations.
  [Related publications: 2410.03591, 2502.20310, 2505.07458]
  
  

• Time: 15:00 - 15:50 | Speaker: Masanori Hanada (Queen Mary University of London, UK)
  Title: Four phases in QCD at finite temperature [N/A]
  Abstract: Partial deconfinement is a generic phenomenon in a wide class of gauge theories, at least at large N. This concept emerged from efforts to understand the negative specific heat of small black hole in AdS5*S5 in terms of dual gauge theory. This talk begins with a concise introduction to the theoretical framework of partial deconfinement. We then examine its generalization within QCD under the Veneziano large-Nc limit, where the ratio Nf/Nc remains fixed, extending the analysis to systems with finite baryon chemical potential. Our investigation reveals that the partially deconfined phase exhibits intricate substructure, leading to a rich phase diagram. Specifically, we identify four distinct phases in QCD at finite temperature and moderate density: complete confinement, complete deconfinement, and two distinct types of partial deconfinement. As a by-product, we identify the mechanism of the emergence of the QCD critical point from the interplay between baryon condensation and partial deconfinement. [Note: The second half represents work in progress.]
  
  

• Time: 16:20 - 17:10 | Speaker: Shinji Mukohyama (Kyoto University, Japan)
  Title: Extending EFT of inflation/dark energy to black hole with timelike scalar profile [PDF]
  Abstract: I extend EFT of inflation/dark energy to arbitrary background with timelike scalar profile. In this framework a set of consistency relations among EFT coefficients ensures the spatial diffeo invariance. I then apply it to black hole perturbation in the presence of dark energy.
  [arxiv numbers: 2204.00228, 2208.02943, 2304.14304, 2405.10813, 2406.04525, 2407.15123, 2503.00520]

• Time: 09:40 - 10:30 | Speaker: Massimo Porrati (New York University, USA)
  Title: Local operator algebras of charged states in gauge theory and gravity [PDF]
  Abstract: Powerful techniques have been developed in quantum field theory that employ algebras of local operators, yet local operators cannot create physical charged states in gauge theory or physical nonzero-energy states in perturbative quantum gravity.  Common methods to obtain physical operators destroy locality and other properties of the local algebra. In this talk, an alternative approach to the definition of physical charged operators is presented. It employs an automorphism that maps the algebra of local charged operators into a (non-local) algebra of physical charged operators while preserving many properties of local algebras. The automorphism is described by a formally unitary intertwiner, which maps the exact BRS operator associated to the gauge symmetry into its quadratic part. Relations to other definitions of gauge invariant operators, available in massive gauge theories, and applications to TTbar deformations will be discussed, together with the obstruction to a formal construction of physical states.
  
  

• Time: 11:00 - 11:50 | Speaker: Pablo A. Cano (University of Barcelona, Spain)
  Title: Dynamical formation of regular black holes [PDF]
  Abstract: I will show that black hole singularities can be resolved by including an infinite tower of higher-derivative corrections to the Einstein-Hilbert action. Within the same framework, I will also show that gravitational collapse of matter leads in general to the formation of these singularity-free black holes. Our results are facilitated by the use of a class of theories that possess second-order equations on spherically symmetric metrics, but which are general enough to provide a basis for the gravitational effective action. These theories predict that the matter that collapses into a black hole inevitably experiences a bounce at a small radius, giving rise to a geodetically complete spacetime.  This construction provides, to the best of our knowledge, the first fully dynamical description of formation of regular black holes, and it suggests that higher-derivative corrections may be the most natural way to resolve the singularities of Einstein’s theory

[References: https://arxiv.org/abs/2403.04827, https://arxiv.org/abs/2412.02740, https://arxiv.org/abs/2412.02742, https://arxiv.org/abs/2505.09680]

• Time: 09:40 - 10:30 | Speaker: Robert de Mello Koch (Huzhou University, China)
  Title: Algebraic structures in loop space at finite N [PDF]
  Abstract: We use the Molien–Weyl formula to compute exact partition functions for a broad class of multi-matrix models, including those coupled to vector and bi-fundamental fields, at finite N. Interpreting these results through trace relations, we identify a complete generating set of gauge-invariant operators, naturally organized into two distinct types: primary and secondary invariants. The full invariant ring is reconstructed via the Hironaka decomposition, in which primary invariants generate the ring freely, while secondary invariants satisfy quadratic relations. Notably, although single-trace operators with at most N matrices are always included, we also find essential invariants involving more than N matrices per trace. The primary invariants correspond to perturbative degrees of freedom, while the secondary invariants encode non-perturbative background structure. Intriguingly, the exponential growth of secondary invariants mirrors the entropy scaling of black holes, hinting at deep structural parallels with gravitational systems.
  [Related arXiv papers are: arXiv:2503.20097 and arXiv:2504.14181]
  
  

• Time: 11:00 - 11:50 | Speaker: Seok Kim (Seoul National University, Korea)
  Title: Cohomologies of ABJ higher spin holography [PDF]
  Abstract: We discuss the BPS states of the supersymmetric Vasiliev higher spin gravity, holographically from the ABJ Chern-Simons-vector matter theory at nonzero 't Hooft coupling. We study the cohomologies of these states, as well as their large N high temperature thermodynamics.
  
  

• Time: 14:00 - 14:50 | Speaker: Marina David (KU Leuven, Belgium)
  Title: Probing extremality via black hole spectroscopy in theories beyond GR [PDF]
  Abstract: Black hole spectroscopy plays a central role in precision tests of gravity, especially in probing new physics beyond General Relativity. In this work, we construct a new class of gravitational effective field theories, having isospectral quasinormal modes in the eikonal limit, and exhibit additional noteworthy features, such as a connection to string theory. We present two methods to compute the eikonal quasinormal modes for all values of the spin, marking the first complete result of this kind in any theory beyond GR. In the near-extremal regime, for large values of the spin, we find interesting features including hints of instability. These unique signatures can serve as “golden events” in the search for new physics.
  [2407.02017, 2407.12080, and another upcoming preprint to be added]
  
  

• Time: 15:00 - 15:50 | Speaker: Keun-Young Kim (GIST, Korea)
  Title: Deep learning-based holography for T-linear resistivity [N/A]
  Abstract: We employ deep learning within holographic duality to investigate T-linear resistivity, a hallmark of strange metals. Utilizing Physics-Informed Neural Networks, we incorporate boundary data for T-linear resistivity and bulk differential equations into a loss function. This approach allows us to derive dilaton potentials in Einstein-Maxwell-Dilaton-Axion theories, capturing essential features of strange metals, such as T-linear resistivity and linear specific heat scaling. We also explore the impact of the resistivity slope on dilaton potentials. Regardless of slope, dilaton potentials exhibit universal exponential growth at low temperatures, driving T-linear resistivity and matching infrared geometric analyses. At a specific slope, our method rediscovers the Gubser-Rocha model, a well-known holographic model of strange metals. Additionally, the robustness of T-linear resistivity at higher temperatures correlates with the asymptotic AdS behavior of the dilaton coupling to the Maxwell term. Our findings suggest that deep learning could help uncover mechanisms in holographic condensed matter systems and advance our understanding of strange metals.

[arXiv number: 2502.10245]

• Time: 16:20 - 17:10 | Speaker: Junggi Yoon (Kyung Hee University, Korea)
  Title: A New Genuine Multipartite Entanglement Measure: from Qubits to Multiboundary Wormholes [PDF]
  Abstract: TBA

• Time: 09:40 - 10:30 | Speaker: Imtak Jeon (Huzhou University, China)
  Title: Supersymmetric localisation of N=(2,2) theories on a spindle [PDF]
  Abstract: We consider two-dimensional $\mathcal{N}=(2,2)$ supersymmteric field theories living on a weighted projective space $\mathbb{WCP}_{[n_1,n_2]}^1$, often referred to as a spindle. Starting from the spindle solution of five-dimensional minimal gauged supergravity, we construct a two-dimensional $\mathcal{N}=(2,2)$ theory on a spindle, preserving supersymmetry via the anti-twist mechanism and admitting two Killing spinors of opposing $R$-charge. We apply the technique of supersymmetric localisation to compute the exact partition function for a theory consisting of an abelian vector multiplet and a chiral multiplet, finding that the path integral localises to a real moduli space of vector multiplet fluctuations. We compute the one-loop determinants via the equivariant index, using both the method of unpaired eigenvalues and the fixed point theorem, finding agreement between the two approaches. We conclude with the explicit example of a charged chiral multiplet in the presence of a Fayet-Iliopoulos term. This work paves the way towards uncovering two-dimensional dualities, such as mirror symmetry, for field theories defined on orbifold backgrounds.

[The arrive number of the related paper is https://arxiv.org/pdf/2506.03734]

• Time: 11:00 - 11:50 | Speaker: René Meyer (University of Würzburg, Germany)
  Title: Aspects of torsion and non-metricity related to holography [PDF]
  Abstract: In this talk I will discuss several aspects of theories with curvature, torsion and non-metricity in the absence and presence of a cosmological constant, i.e. also in relation to holography. After an overview over the topic, I will in particular discuss a derivation of the universal Gibbons-Hawking-York boundary term necessary for the variational principle in all theories with curvature, torsion and non-metricity [1]. The method employed in [1] consists of linearizing any nonlinearity in curvature, torsion or non-metricity by introducing suitable Lagrange multipliers. Moreover, a split formalism for differential forms is used, in which the boundary terms of the action are manifest by means of Stokes' theorem, such that the compensating GHY term for the Dirichlet problem may be read off directly. I observe that only those terms in the Lagrangian that contain curvature contribute to the GHY term. I furthermore confirm existing results for Einstein-Hilbert and four-dimensional Chern-Simons modified gravity, and obtain new results for Lovelock-Chern-Simons and metric-affine gravity.  In the second part of this talk, I will discuss the correct treatment of the boundary terms [2] in the geometric trinity of Einstein-Hilbert (curvature only), teleparallel (torsion only) and symmetric teleparallel (non-metricity only) gravity. I in particular show that the GHY term for both TEGR and STEGR must vanish for consistency of the variational problem. Furthermore, I discuss how this approach allows to extend the equivalence between GR, TEGR and STEGR beyond the Einstein-Hilbert action to any action built out of the curvature two-form, thus establishing the generalized geometrical trinity of gravity. I end up with a discussion how these results will be useful in the context of holography, in particular in understanding the emergence of spinfull hydrodynamics from AdS/CFT.
  [This talk is based upon the following two publications:
  [1] https://arxiv.org/abs/2211.02064 [2] https://arxiv.org/abs/2304.06752]