Program

March 13 (Mon)

10:00 - 11:00
Satoshi Yamaguchi "Non-invertible symmetries and disk partition functions"
Abstract: Recently, the concept of symmetry has been generalized, and what was not traditionally called symmetry is now being used similarly as symmetry. In this talk, we discuss a class of such generalized symmetries, called non-invertible symmetries, from the viewpoint of the lattice field theories. In particular, we construct topological defects in four-dimensional Z_2 lattice gauge theory, including the Kramers-Wannier-Wegner (KWW) duality defect; the KWW duality defect is an example of non-invertible symmetries. Also, we consider the system with a boundary and discuss the relations between the disk partition functions derived from the non-invertible symmetry.

11:30 – 12:30 
Kantaro Ohmori "Fusion Surface Models: 2+1d Lattice Models from Higher Categories" slide

14:00 – 15:00
Emily Nardoni "Probing Anomalies of Non-Invertible Symmetries with Symmetry TFTs" slide
Abstract: 't Hooft anomalies provide crucial insight into the properties of quantum field theories, imposing powerful constraints on their low energy dynamics. For invertible global symmetries, it is known that the 't Hooft anomalies can be characterized by an invertible TQFT in one higher dimension. However, the analogous statement remains to be understood for non-invertible symmetries. In this talk we will discuss how the linking invariants in a non-invertible TQFT known as the Symmetry TFT can be used as a diagnostic for the anomalies of non-invertible symmetries. We will illustrate this proposal through examples in two and four dimensions, including 4d adjoint QCD, and comment on how knowledge of these anomalies can impose constraints on the dynamics.

15:30 – 16:30
Naoto Kan “A microscopic description of the Witten effect with negatively massive fermions” slide

Abstract: Inside topological insulators or in the theta=pi vacuum, magnetic monopoles gain fractional electric charges, which is known as the Witten effect. In this work, we try to give a microscopic description for this phenomenon, solving a "negatively" massive Dirac equation. The "Wilson term" plays a key role in 1) identifying the sign of the fermion mass, 2) confirming evidence for dynamical domain-wall creations, and 3) understanding why the electric charge is fractional.

16:45 – Discussion

March 14 (Tue)

10:00 – 11:00
Jaewon Song “Emergent N=4 supersymmetry from N=1” slide

11:30 – 12:30
Tomoki Nakanishi "$S^1$ Reduction of 4D $¥mathcal{N}=3$ SCFTs and Squashing Independence of ABJM theories" slide
Abstract: We study the compactification of 4D $¥mathcal{N}=3$ superconformal field theories (SCFTs) on $S^1$, focusing on the relation between the 4D superconformal index and 3D partition function on the squashed sphere $S^3_b$. Since the center $¥mathfrak{u}(1)$ of the $¥mathfrak{u}(3)$ R-symmetry of the 4D theory can mix with an $¥mathcal{N}=6$ abelian flavor symmetry in three dimensions, the precise 4D/3D relation for the global symmetry is not obvious. Focusing on the case in which the 3D theory is the ABJM theory, we demonstrate that the above R-symmetry mixing can be precisely identified by considering the Schur limit (and/or its $¥mathcal{N}=3$ cousin) of the 4D index. As a result, we generalize to the ABJM theories recent discussions on the connection between supersymmetry enhancement of the 4D index and squashing independence of the $S^3_b$ partition function. 

14:00 – 15:00
Yutaka Yoshida "Open string Witten indices of 2d $¥mathcal{N}=(2,2)$ GLSMs"
Abstract: In our previous work, we have derived a supersymmetric localization formula for indices of 2d $¥mathcal{N}=(2,2)$ gauged linear sigma models (GLSMs) on $I ¥times S^1$. In this talk, we consider the localization formula in the Landau-Ginzburg(LG) phase and discuss  BPS boundary conditions which reproduce  cylinder amplitudes with Recknagel-Schomerus boundary states in Gepner models.

15:30 – 16:30
Hee-Cheol Kim “Blowup Equations for 5d/6d theories” slide
Abstract: I will talk about the blowup equations for 5d/6d supersymmetric QFTs and little string theories which generalize Nakajima-Yoshioka's blowup equations for the instanton partition functions 

of the 4d/5d gauge theories on Omega background.

16:45 – Discussion

March 15 (Wed)

10:00 – 11:00
Kazutoshi Ohta "Graph Zeta Functions and Kazakov-Migdal Model” slide

Abstract: We consider a generalized Kazakov-Migdal model defined on an arbitrary graph. The partition function of the model can be represented by the unitary matrix integral of the weighted graph zeta functions, which have series expansions by possible Wilson loops (graph cycles). The partition function of the model is expressed in two different ways according to the order of integration. A specific unitary matrix integral can be performed even at finite N, thanks to this duality. In addition, we evaluate exactly the partition function of the Kazakov-Migdal model on the graph in the large N limit and show that it is expressed by the infinite product of the graph zeta functions. We also discuss an extension including the bumps, the random matrix model approach, and the Gross-Witten-Wadia phase transition.

11:30 – 12:30
Hiroshi Itoyama "Critical hypersurface of su(n) gauge theory with flavors from A_{n-1} multi matrix model" slide