New advancements on defects and their applications

Contribution List

2. Tzu-Chieh Wei: Kennedy-Tasaki transformation and non-invertible symmetry in lattice models beyond one dimension

7/14/25, 10:00 AM

Symmetry-protected topological phases are dual to spontaneous symmetry-breaking phases, recognized by Kennedy and Tasaki using a non-local transformation (i.e., KT transformation). On the symmetry-breaking side, Kramers-Wannier duality transformation was long known to map between ordered phase (i.e., symmetry-breaking phase) and symmetry-preserving phase (i.e., disordered phase). There has...

4. Sungjay Lee

7/14/25, 11:30 AM

5. Kenta Suzuki: Time-like Janus Solution - Holographic Global Quench and Thermalization

7/14/25, 2:00 PM

The usual space-like Janus solution is an AdS_d slicing of AdS_{d+1} with mediated by a massless dilaton field depending on the slicing coordinate. In this talk, we construct a time-like Janus solution, which is a dS_d slicing of AdS_{d+1} with mediated by a time-dependent massless dilaton field. Even though this solution breaks the null energy condition, we argue that the solution is...

6. Taishi Kawamoto: AdS3 wormhole via non-local TT bar deformation or imaginary Janus deformation

7/14/25, 2:30 PM

Wormholes are important objects in quantum gravity. Especially traversable wormhole in AdS is important since they casually relate the distinguished boundary theories and allows information transfer among them. So far the constructing wormhole is typically done in low dimensional gravity related to SYK model or the level of gravitational perturbation. In this talk, we introduce two novel...

7. Yuefeng Liu: Non-conformal line defects and ETH in AdS3/CFT2

7/14/25, 3:30 PM

Defects in QFT can touch non-local correlations which are usually blank to local operators. In CFT, topological defects and conformal defects are under active research due to large symmetries they have. For non-conformal defects it is generally hard to have analytic control. However, inspired by recent works on wormholes and chaotic statistics of high energy sector of AdS/CFT system, a special...

21. Arpit Das: Anomalies and Entanglement: Twist Field Approach to Non-Invertible Symmetries in RCFTs

7/14/25, 4:00 PM

In this talk, I will present an approach to Symmetry Resolved Entanglement Entropy based on the twist field formalism. I will construct twist fields corresponding to non-invertible symmetries in two-dimensional Rational Conformal Field Theories (RCFTs) and demonstrate their connection to 't Hooft anomalies. These anomalies, manifesting as the absence of scalar primaries in twisted symmetry...

8. Giuseppe Policastro

7/15/25, 10:00 AM

9. Yuya Kusuki: New Crosscap States from Non-invertible Symmetries

7/15/25, 11:30 AM

We investigate crosscap states in two-dimensional rational conformal field theories (RCFTs), with a particular emphasis on the role of symmetries, including non-invertible ones. In this work, we develop a systematic bootstrap framework that incorporates both crosscaps and topological interfaces, leading to explicit solutions that reveal new classes of crosscap states beyond previously known...

10. Jesper Jacobsen

7/15/25, 2:00 PM

22. Mahesh Balasubramanian: Topological surface defects in 2+1d, and gauging of non-invertible symmetries

7/15/25, 3:30 PM

We describe non-invertible symmetries of 2+1d TQFTs and their twisted sectors in terms of connected fusion 2-categories. We rephrase these objects in the familiar language of QFT whenever possible, and for 2+1d Z_{2} gauge theory, we describe gauging of these non-invertible symmetries and their inversion using Anyon condensation.

24. Zi-Xiao Huang: From Weyl Anomaly to Universal Surface Defect Entropy and Casimir Energy

7/15/25, 3:50 PM

Defects serve as a key tool for understanding the non-perturbative properties of the quantum field theory. In general, defect insertions lead to nontrivial contributions to observables including entanglement measure and the ground state energy. We establish a universal relation between surface defect Weyl anomalies and the entanglement measure in higher-dimensional quantum field theories. In...

25. Kazuki Doi: Entanglement Suppression Due to Black Hole Scattering

7/15/25, 4:10 PM

We consider the evolution of entanglement entropy in a two-dimensional conformal field theory with a holographic dual. Specifically, we are interested in a class of excited states produced by a combination of pure-state and mixed-state local operator quenches. While we expect a logarithmic time dependence of entanglement entropy relative to the vacuum in the case of the insertion of a single...

11. Charlotte Kristjansen: Quantum Quenches from Quantum Fields

7/16/25, 10:00 AM

An integrable spin chain underlies the celebrated AdS/CFT duality. Overlaps between matrix product states and Bethe eigenstates of the chain contain information both about correlation functions of the quantum field theory entering the duality and about the behavior of the spin chain after a quantum quench. I will explain how such overlaps can be calculated exactly.

12. Bowen Shi: Homogeneity versus defect: an entanglement bootstrap view

7/16/25, 11:30 AM

Defects break homogeneity by definition. To talk about defects, a sense of homogeneity should be established first. We introduce the entanglement bootstrap view of this problem, which takes a many-body vacuum state as the input instead of a Hamiltonian or Lagrangian. In a nutshell, the entanglement bootstrap imposes a set of local axioms on the wave function to guarantee the space is "uniform...

13. Yu Nakayama: (Non-) Factorizing Defect

7/16/25, 2:00 PM

I discuss (non-) factorizing defect or interface in Kyoto and in the (long-range) Ising model. The scientific part of my talk is based on a collaboration with Dongsheng Ge.

14. Janet Hung: A 2D-CFT Factory: Critical Lattice Models from Competing Anyon Condensation in SymTO/SymTFT

7/17/25, 10:00 AM

In this talk, we introduce a ``CFT factory'' : a novel algorithm of methodically generating 2D lattice models that would flow to 2D conformal fixed points in the infrared. These 2D models are realised by giving critical boundary conditions to 3D topological orders (symTOs/symTFTs) described by string-net models, often called the strange correlators. We engineer these critical boundary...

15. John Estes: (Super)Conformal defects and boundaries in holography

7/17/25, 11:30 AM

I will give an overview of the geometric features arising in the holographic description of CFTs with conformal defects or boundaries. Weyl anomalies arising in such theories have a rich structure, as they are less restricted by Lorentz invariance. Entanglement entropy arises naturally as a way to characterize the defects and boundaries, and provides an effective tool for determining certain...

16. Mitchell Weaver:Reading between the Special Kähler Structures of Coulomb branch geometries: N=4 sYM

7/17/25, 2:00 PM

Quantum field theories (QFTs) possess both local data, e.g. the spectrum and OPEs of local operators, and global data. Global data determines the topologically non-trivial manifolds the theory can be placed on, and the distinct sets of such data define the global variants of the QFT, all of which contain the same local data. For gauge theories, global variants are described by the (maximal)...

23. Yongchao Lu: On Exact solutions in Superconformal Indices for N=2 Super Yang mills theories

7/17/25, 2:30 PM

The superconformal index (SCI) provides a powerful non-perturbative tool for investigating supersymmetric quantum field theories, particularly in the presence of BPS defects. In this talk, I will present exact closed-form solutions of the SCI for 4d N=2 super Yang–Mills theories with all simple gauge groups (types A, B, C, D, E, F, and G). These solutions exhibit a unified mathematical...

19. Ma-Ke Yuan: Rényi Entropy with Surface Defects in Six Dimensions

7/17/25, 3:30 PM

Defect operators in quantum field theory have attracted significant attention in recent years. Meanwhile, quantum information measures—such as Rényi entropy—provide powerful tools to probe quantum field theories. In this talk, I will focus on surface defects in 6d (2,0) theories and their contributions to the Rényi entropy and supersymmetric Rényi entropy. Remarkably, the contribution to...

20. Kenya Tasuki: Multi-entropy at Ising Criticality

7/17/25, 3:50 PM

Multi-entropy, a recently introduced generalization of bipartite entanglement entropy, has been proposed as a powerful probe of multipartite correlations; however, it has been little explored in explicit calculations for many-body systems so far. We investigate its scaling behavior in the one-dimensional transverse-field Ising model near the critical point. Numerical results from tensor...

17. Valentina Forini: Conformal field theories from line defects, holography and the analytic bootstrap

7/18/25, 10:00 AM

Wilson lines are a prototypical example of defect in quantum field theory. After reviewing the superconformal case - in which the one-dimensional defect CFT that they define is particularly interesting - I will discuss some analytic tools that may prove useful in this context, but are developed for generic 1d CFTs. Among them, a representation of the four-point correlator as a Mellin amplitude...

18. Xi Yin: The unreasonable effectiveness of D-instantons

7/18/25, 11:30 AM

I will review a first-principle approach to D-instanton effects based on string field theory, and discuss a new result on the non-perturbative effective action of D3-branes that hints at unexplained structures in the non-BPS sector. The latter is based on upcoming work with Jaroslav Scheinpflug and Yuchen Wang.