Conformal boundary condition and AdS/BCFT

• Chong-Sun Chu (National Tsing-Hua U)

Conformal boundary condition was previously considered in the context of AdS/BCFT, wherein the equation of motion of the end-of-the-world was derived and emphasized. In this talk, I will discuss some other further consequences of the conformal boundary condition in AdS/BCFT. We derive the boundary central charges of the holographic Weyl anomaly. We analysis the metric perturbation on the end-of-the-world brane with different boundary conditions. Our results reveal that there are non-trivial gravitational dynamics from extrinsic curvatures on the conformal and Dirichlet branes, which may have interesting applications to the island.

Yang-Baxter sigma models from 4D Chern-Simons theory

• Kentaroh Yoshida (Kyoto U)

Recently, a 4D Cherns-Simons (CS) theory has been proposed by Costello and Yamazaki as a unified theory of 2D classically integrable field theories. In this talk, I will explain how to derive Yang-Baxter sigma models from this 4D CS theory.

On Galilean Conformal Bootstrap

• Bin Chen (PKU)

In the past decade, the renaissance of conformal bootstrap has enriched our understanding of conformal field theory and AdS/CFT correspondence. It would be interesting to develop the bootstrap program for other field theories with conformal-like symmetries. In this talk, I will introduce our studies on Galilean conformal bootstrap in the past few years.

Anomalies and Supersymmetry

• Piljin Yi (KIAS)

Anomaly of subsystem symmetry and anomaly inflow

• Satoshi Yamaguchi (Osaka U)

Weak Cosmic Censorship for Higher Derivative Gravity Theories

• Feng-Li Lin (National Taiwan Normal U)

In this talk I will discuss how the weak cosmic censorship conjecture (WCCC) constrains the higher derivative gravity theories based on Wald's gedanken experiment by throwing the matter into the extremal or near-extremal black holes. We find that even though the WCCC still holds for the extremal black hole for the extremal black holes of quartic gravity theories, it can be violated for the near-extremal cases.

Twisted Compactification of 6d SCFTs

• Kimyeong Lee (KIAS)

In this talk, we consider the circle compactification of 6d superconformal field theories with twist. Especially, we focus on how to obtain their Omega-deformed partition functions and take their Cardy limit. We comment on its relation to the black hole physics.

How to multiply, add and expand amplitudes in theory space

• Song He (ITP)

Penrose Limit: A Stringy Regime in Holography

• Min-xin Huang (USTC)

Penrose limit provides a promising avenue to the stringy regime in the AdS/CFT holography, giving rise to the pp-wave background. Recently, we proposed a novel entry of the pp-wave holographic dictionary, which equated the Berenstein-Maldacena-Nastase (BMN) two-point functions in free Yang-Mills theory with the norm squares of the quantum unitary transition amplitudes between the corresponding tensionless strings in the infinite curvature limit. If our proposal is correct, it would not only provide first examples of systematic calculations of the higher genus critical superstring amplitudes, but may also in principle gives exact complete results for any string coupling, due to the convergence of genus expansion.

Quantum black holes from matrix models

• Seok Kim (Seoul National U)

I will explain the microscopic studies of BPS black holes in AdS from matrix models

Finite-N superconformal index via the AdS/CFT correspondence

• Yosuke Imamura (Tokyo Inst Tech)

We propose a prescription to calculate the superconformal index of the N=4 U(N) supersymmetric Yang-Mills theory with finite N on the AdS side. The finite N corrections are included as contributions of D3-branes wrapped around three-cycles in S5, which are calculated as the index of the gauge theories realized on the wrapped branes.

Conformal anomalies a vs c

• Jaewon Song (KAIST)

FZZT branes in JT gravity and topological gravity

• Kazumi Okuyama (Shinshu U)

3D rank 0 N=4 SCFTs and Non-unitary TQFTs

• Dongmin Gang (Seoul National U)

Emergent Supersymmetry on the Edges

• Sungjay Lee (KIAS)

What happens when conifold transitions occur at the conifold singularities associated with matter generation in F-theory?

• Shun'ya Mizoguchi (KEK)

A conifold is a singular Calabi-Yau 3-fold of the simplest type, and has played important roles in various aspects of string theory. In fact, in F-theory, conifold singularities are quite commonplace; conifold singularities typically appear, in “split models”, in most places where charged matter is generated. We show that the split/non-split transition is, except in certain exceptional cases, a conifold transition from the resolved to the deformed side, associated with the conifold singularities emerging where the codimension-one singularity is enhanced to D_{2k+2} (k ≥ 1) or E_7. This clarifies the origin of nonlocal matter in the non-split models, which has been a mystery for many years.

Digital quantum simulation of the Schwinger model with topological term

• Masazumi Honda (YITP)

5d/6d Wilson loops from blowups

• Hee-Cheol Kim (POSTECH)

Gravitational Positivity Bounds and the Standard Model

• Toshifumi Noumi (Kobe U)

Positivity bounds on low-energy scattering amplitudes provide a criterion for a low-energy effective theory to have a standard UV completion. When applied to gravitational theories, they are expected to imply non-trivial quantum gravity constraints on quantum field theory models, i.e., swampland conditions. In this talk I will introduce recent developments on positivity bounds in gravitational theories and their implications for the Standard Model of particle physics.

M2-branes & Quantum Curves

• Sanefumi Moriyama (Osaka City U)

Bounds on gravitational S matrix

• Yu-tin Huang (National Taiwan U)

Machine Learning Exploration of Continuous Symmetries in Physical Systems

• Heng-Yu Chen (National Taiwan U)

Anisotropic Holography

• Dimitrios Giataganas (National Sun Yat-sen U)

Strongly coupled anisotropic systems have significantly richer structure than the isotropic ones. This is especially evident in the transport coefficients and in the phase diagram of anisotropic theories. We discuss such holographic theories, we comment on their observables and demonstrate how the isotropic universal relations are violated in presence of anisotropies. We also propose c-function candidates for the anisotropic RG flows and show that their monotonicity is not any more guaranteed by the energy conditions but depends on the theory characteristics.

Compactness, Finiteness, and the Swampland

• Yuta Hamada (Harvard)

We demonstrate the validity of the String Lamppost Principle – that all consistent theories of quantum gravity are in the String Landscape – for supersymmetric theories in d > 6 using compactness and connectedness of the moduli space of small instantons, as well as the classification of the associated Coulomb branch. We also argue that some of the swampland conjectures are viewed as the prism of the finiteness of black hole entropy.

Topological pseudo entropy

• Tatsuma Nishioka (YITP)

Causal Shadow and modular flow in AdS/CFT: the degenerate case

• Huajia Wang (KITP)

Defect Extremal Surface and Partial Reduction

• Yang Zhou (Fudan U)

Kramers-Wannier-like duality defects in (3 + 1)d gauge theories

• Kantaro Ohmori (U of Toyo)

The 1+1d Majorana fermion has a chiral Z2 symmetry, which is "broken" after gauging the non-chiral fermion parity due to their mixed anomaly. However, it is better to think that the symmetry is preserved even after gauging, in the form of topological defect, and the defect implements the Kramers-Wannier self-duality of the Ising CFT. In this talk I will talk about an analogue of this story for some examples of (3+1)d continuum QFTs. In particular I will explicitly construct topological defects associated to self-dualities under gauging a one-form (aka center) symmetry of QFTs.

A BMS-invariant free scalar model

• Wei Song (Tsinghua U)

The BMS (Bondi-van der Burg-Metzner-Sachs) symmetry arises as the asymptotic symmetry of flat spacetime at null infinity, suggesting a holographic duality between Einstein gravity and some quantum field theory with BMS invariance. In particular, the BMS algebra in three dimensions is generated by super-rotation generators which form a Virasoro sub-algebra, together with mutually-commuting super-translation generators. In this talk, I will first review flat holography in three dimensions, and then describe a free scalar model in two dimensions exhibiting BMS symmetry.

Heavy-Heavy-Light Three-Point Functions from D-branes Revisited

• Jun-Bao Wu (Tianjin University)

We study correlation functions of D-branes and a supergravity mode in AdS, which are dual to structure constants of two sub-determinant operators with large charge and a BPS single-trace operator. Our approach is inspired by the large charge expansion of CFT and resolves puzzles and confusions in the literature on the holographic computation of correlation functions of heavy operators. In particular, we point out two important effects which are often missed in the literature; the first one is an average over classical configurations of the heavy state, which physically amounts to projecting the state to an eigenstate of quantum numbers. The second one is the contribution from wave functions of the heavy state. To demonstrate the power of the method, we first analyze the three-point functions in N=4 super Yang-Mills and reproduce the results in field theory from holography, including the cases for which the previous holographic computation gives incorrect answers. We then apply it to ABJM theory and make solid predictions at strong coupling. Finally we comment on possible applications to states dual to black holes and fuzzballs. This talk is based on work done with Peihe Yang, Yunfeng Jiang and Shota Komatsu.

Effective Theory Breaks Down at Scrambling Time

• Pei-Ming Ho (National Taiwan U)

For the background of a gravitational collapse, we calculate the amplitudes for infalling matter to radiate outgoing massless particles through higher-derivative interactions. The amplitudes are found to grow exponentially with time, leading to the breakdown of the effective theory at the scrambling time.