East Asia Joint Symposium on Fields and Strings 2021

22 Nov 2021, 09:00 → 27 Nov 2021, 17:00 Asia/Tokyo

10th floor of Media Center, Osaka City University, Osaka, Japan & Zoom

Sponsored by Nambu Yoichiro Institute of Theoretical and Experimental Phyiscs (NITEP), Osaka City University and by Asia Pasific Center for Theoretical Physics (APCTP)
Dates: November 22-27 2021
Conference venue: 10th floor of Media Center, Osaka City University, Osaka, Japan & Zoom

Deadline for abstract submission to short talk/poster presentation is 10 October, 2021. Abstract submission is closed.

Deadline for registration is 15 November, 2021. Registration is closed.

For more details, please read the  ``Circulars" in the left menu.

 

Announcement:

[22 Nov.] The short talk by Masataka Koide is cancelled. The program of the short talk session which starts at 15:45, 22 Nov. is modified.

 

International Organizing Committee:

C. S. Chu (National Tsing-Hua U), S. Iso (KEK), K. Lee (KIAS), J. Lu (USTC Hefei)

 

Organizing Committee:

M. Honda (YITP), Y. Imamura (Tokyo Inst Tech), S. Iso (KEK), H. Itoyama (Osaka City U, Chair), K. Maruyoshi (Seikei U), S. Mizoguchi (KEK), S. Moriyama (Osaka City U), T. Nishinaka (Osaka City U), T. Oota (Osaka City U), K. Sakai (Meiji Gakuin U), A. Tsuchiya (Shizuoka U), S. Yamaguchi (Osaka U), K. Yoshida (Kyoto U), R. Yoshioka (Osaka City U)

EAJS2021program1122.pdf EAJS2021v3.pdf

Conference Photos

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Monday, 22 November

09:30 → 09:45 Opening

09:30 Opening

Hiroshi Itoyama (Osaka City U)

09:45 → 10:15 Conformal boundary condition and AdS/BCFT

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.

Speaker: Chong-Sun Chu (National Tsing-Hua U)

10:15 → 10:45 Yang-Baxter sigma models from 4D Chern-Simons theory

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.

Speaker: Kentaroh Yoshida (Kyoto U)

Yoshida_EAJS-2021.pptx

10:45 → 11:15 Coffee Break

11:15 → 11:45 On Galilean Conformal Bootstrap

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.

Speaker: Bin Chen (PKU)

Bin Chen_GCAEAJS.pdf

11:45 → 12:15 Short talks

11:45 Order defect in 4D Chern-Simons theory

The 4D Chern-Simons (CS) theory is a unifying framework of 2D integrable field theories and lattice models. Derivations of integrable field theories from 4D CS theories are based on two classes: order and disorder defects. We develop the aspect of order defects, and derive integrable field theories such as the Faddeev-Reshetikhin model. This approach further admits integrable deformations of the model by adopting appropriate boundary conditions.

Speaker: Osamu Fukushima (Kyoto University)

12:00 The AdS5×S5 superstring from 4D Chern-Simons theory

Recently, a unified picture to describe integrable systems has been established by Costello, Witten and Yamazaki. In the case of 2D integrable field theories, Costello and Yamazaki proposed that by starting from a certain 4D Chern-Simons (CS) theory, one can construct classically integrable field theories systematically by taking a meromorphic 1-form and adopting an appropriate boundary condition. In this talk, I will explain how the AdS5×S5 supercoset sigma model and its integrable deformations can be reproduced from a 4D CS theory by generalizing the procedure for the 2D principal chiral model developed by Delduc et al [arXiv:1909.13824].
This talk is based on works (2003.07309, 2005.04950) with Osamu Fukushima and Kentaroh Yoshida in Kyoto University.

Speaker: Junichi Sakamoto

12:15 → 13:45 Lunch Break

13:45 → 14:15 Anomalies and Supersymmetry

Speaker: Piljin Yi (KIAS)

Piljin Yi_2021 SUSY and Anomaly Osaka_v2.pdf

14:15 → 14:45 Short talks

14:15 A physicist-friendly reformulation of the APS index (on a lattice)

The Atiyah-Singer(AS) index theorem on a closed manifold is well understood and appreciated in physics. On the other hand, the Atiyah-Patodi-Singer(APS) index, which is an extension to a manifold with boundary, is physicist-unfriendly, in that it is formulated with a nonlocal boundary condition. Recently we (3 physicists and 3 mathematicians) proved that the same index as APS is obtained from the domain-wall fermion Dirac operator. Our theorem indicates that the index can be expressed without any nonlocal conditions, in such a physicist-friendly way that application to the lattice gauge theory is straightforward. The domain-wall fermion provides a natural mathematical foundation for understanding the bulk-edge correspondence of the anomaly inflow.

Speaker: Hidenori Fukaya (Osaka U)

Fukaya-APSDW.pdf

14:30 Chaotic string dynamics in deformed $𝑇^{1,1}$

Recently, Arutyunov, Bassi and Lacroix have shown that 2D non-linear sigma model with a deformed T1,1 background is classically integrable. This background includes a Kalb-Ramond two-form with a critical value. Then the sigma model has been conjectured to be non-integrable when the two-form is off critical. With a winding string ansatz, the system is reduced to a dynamical system described by a set of ordinary differential equations. Then we find classical chaos by numerically computing Poincaré sections and Lyapunov spectra for some initial conditions.

Speaker: Shodai Kushiro (Kyoto U)

14:45 → 15:15 Coffee Break

15:15 → 15:45 Anomaly of subsystem symmetry and anomaly inflow

Speaker: Satoshi Yamaguchi (Osaka U)

yamaguchi.pdf

15:45 → 16:15 Short talks

15:45 Topological defect junctions in 4-dimensional pure Z2 gauge theory

Recently, there are many studies about expanding concepts of symmetries and its applications. One of the directions is to treat non-invertible objects as ""symmetry"". We explicitly constructed a non-invertible defect of duality and a 1-form center symmetry defect in 4D lattice pure Z2 gauge theory. In this talk, we will describe the junction that occurs where the two defects overlap. The duality operator is non-invertible, so it is not necessary to be invariant under deformations that change the topology. We can make the topological relational closed for such deformations including 1-form center symmetry defects and junctions. This work is in collaboration with M.koide and S.Yamaguchi.

Speaker: Yuta Nagoya (Osaka U)

16:00 Three-Body Effective Potential in General Relativity at 2PM and Resulting PN Contributions

In this talk, I will talk about the Post-Newtonian expansion of the gravitational three-body effective potential at the 2nd Post-Minkowskian order. At order 2PM a formal result is given in terms of a differential operator acting on the maximal generalized cut of the one-loop triangle integral. We perform the PN expansion unambiguously at the level of the integrand. Finding agreement with the 2PN three-body potential after integration, we explicitly present new G^2 v^4-contributions at order 3PN and outline the generalization to G^2 v^{2n}. The integrals that represent the essential input for these results respect a non-local Yangian symmetry and are obtained by applying the recent bootstrapping method directly to their ε-expansion around three dimensions. The coordinate space Yangian generator that we employ to obtain these integrals can be understood as a special conformal symmetry in a dual momentum space. If time permits, I will also talk about our work in progress on finding such integrals of generic half-integer propagator powers.

Speaker: Tianheng Wang (Institute of Theoretical Physics of the Chinese Academy of Science, Humboldt University of Berlin)

16:15 → 17:00 Coffee Break

17:00 → 17:30 Short talks

17:00 On compatibility between Conformal symmetry and Continuous higher-form symmetries

We will discuss the compatibility between the conformal symmetry together with the unitarity and the continuous higher-form symmetries. We show that the d-dimensional unitary conformal field theories are not consistent with continuous p-form symmetries for certain (d,p), assuming that the corresponding conserved current is a conformal primary operator. We further discuss several dynamical applications of this constraint. In particular, we show that some gapless, scale invariant quantum field theories are not CFTs.

Speaker: Yunqin Zheng (Kavli IPMU, ISSP, U.Tokyo)

Yunqin Zheng_AsianString_11222021.pdf

17:15 Multi-Soliton Dynamics of Anti-Self-Dual Gauge Fields

We study dynamics of multi-soliton solutions of anti-self-dual Yang-Mills equations for G = GL(2, C) in four-dimensional spaces. The one-soliton solution can be interpreted as a codimension-one soliton in four-dimensional spaces because the principal peak of action density localizes on a three-dimensional hyperplane. We call it the soliton wall. We prove that in the asymptotic region, the n-soliton solution possesses n isolated localized lumps of action density, and interpret it as n intersecting soliton walls. More precisely, each action density lump is essentially the same as a soliton wall because it preserves its shape and ""velocity"" except for a position shift of principal peak in the scattering process. The position shift results from the nonlinear interactions of the multi-solitons and is called the phase shift. We calculate the phase shift factors explicitly and ?find that the action densities can be real-valued in three kind of signatures. Finally, we show that the gauge group can be G = SU(2) in the Ultrahyperbolic space U (the split signature (+,+,-,-). This implies that the intersecting soliton walls could be realized in all region in N=2 string theories. It is remarkable that quasideterminants dramatically simplify the calculations and proofs.

Speaker: Shan-Chi Huang (Nagoya U)

Shan-Chi Huang_EAJS on Fields and Strings_2021.pdf

17:30 → 18:00 Weak Cosmic Censorship for Higher Derivative Gravity Theories

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.

Speaker: Feng-Li Lin (National Taiwan Normal U)

Feng-Li Lin_WCCC_2021.pdf

Tuesday, 23 November

09:30 → 10:00 Twisted Compactification of 6d SCFTs

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.

Speaker: Kimyeong Lee (KIAS)

Kimyeong Lee_Osaka2021Nov.pdf

10:00 → 10:30 How to multiply, add and expand amplitudes in theory space

Speaker: Song He (ITP)

10:30 → 11:00 Coffee Break

11:00 → 11:30 Penrose Limit: A Stringy Regime in Holography

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.

Speaker: Min-xin Huang (USTC)

Minxin Huang_talkppwave9.pdf

11:30 → 12:00 Short talks

11:30 Regge conformal blocks from the Rindler-AdS black hole and the pole-skipping phenomena

We study a holographic construction of conformal blocks in the Regge limit of four-point scalar correlation functions by using coordinates of the two-sided Rindler-AdS black hole. As a generalization of geodesic Witten diagrams, we construct diagrams with four external scalar fields in the Rindler-AdS black hole by integrating over two half-geodesics between the centers of Penrose diagrams and points at the AdS boundary. We demonstrate that late-time behaviors of the diagrams coincide with the Regge behaviors of conformal blocks. We also point out their relevance with the pole-skipping phenomena by showing that the near-horizon analysis of symmetric traceless fields with any integer spin in the Rindler-AdS black hole can capture the Regge behaviors of conformal blocks.

Speaker: Mitsuhiro Nishida (Gwangju Institute of Science and Technology)

Mitsuhiro_Nishida_EAJS2021.pdf

11:45 Aspects of 5d Seiberg-Witten Theories on S^1

We study the 5D N=1 Yang-Mills theory compactified on a circle, focusing on the Coulomb branch. The compactified theory has a very complicated wall-crossing pattern, but on the other hand, there seems to be no wall-crossing for 5d theory. In this talk, I will keep track of the wall-crossing phenomenon from compactified theory to its 5d limit, and see how the wall-crossing turns off. We find the elliptic genera of magnetic BPS strings do wall-cross and retain the memory of 4d wall-crossings.

Speaker: Qiang Jia (KIAS)

JQ-15.pdf

12:00 → 13:30 Lunch Break

13:30 → 14:00 Quantum black holes from matrix models

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

Speaker: Seok Kim (Seoul National U)

Seok Kim_east-asian-2021.pdf

14:00 → 14:30 Finite-N superconformal index via the AdS/CFT correspondence

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.

Speaker: Yosuke Imamura (Tokyo Inst Tech)

eajs1123imamura.pdf

14:30 → 15:00 Short talks

14:30 $E$-strings, $E_8$ Weyl invariant Jacobi forms and Conway invariant Jacobi forms on Leech lattice

In 1992 Wirthmuller showed that for any root system of type A,B,C,D,G,F and E6,E7, the ring of weak Jacobi forms invariant under Weyl group is a polynomial algebra. However, it has recently been proved that for E8 the ring is not a polynomial algebra. I will present how to describe E8 Weyl invariant Jacobi forms properly, both weak and holomorphic, and also how to used them in the modular bootstrap of elliptic genera of E-strings. For example, we prove that for any Weyl invariant E8 Jacobi form \phi_t of index t the function E4^[t/5]\Delta^[5t/6]\phi_t can be expressed uniquely as a polynomial in E4, E6 and Sakai's nine Ai, Bj forms. This is based on a joint work with Haowu Wang arXiv:2109.10578.

Speaker: Kaiwen Sun (KIAS)

Kaiwen Sun Osaka_2021 v3.pdf

14:45 Wall-crossing of TBA equations and WKB periods for the higher order ODE

We study the WKB periods for the $(r+1)$-th order ordinary differential equation (ODE) with polynomial potential which is obtained by the Nekrasov-Shatashvili limit of $(A_r, A_N)$ Argyres-Douglas theory in Omega background. We derive the thermodynamic Bethe ansatz (TBA) equations governing the exact WKB periods, which provides a generalization of the ODE/IM correspondence. Varying the moduli space parameters of the potential, one observes the wall-crossing of the TBA equations. When the potential is monomimal type, we show the TBA equations obtained from the $(A_2, A_2)$ and $(A_2, A_3)$-type ODE lead to the $D_4$ and $E_6$-type TBA equations respectively. This talk is based on the work (hep-th/2104.13680) in collaboration with Katsushi Ito, Takayasu Kondo and Kohei Kuroda and the work in progress.

Speaker: Hongfei Shu (Beijing Institute of Mathematical Sciences and Applications (BIMSA))

Hongfei Shu_EAJS_Talk.pdf

15:00 → 15:30 Coffee Break

15:30 → 16:00 Conformal anomalies a vs c

Speaker: Jaewon Song (KAIST)

Jaewon Song_EAJS2021.pdf

16:00 → 16:30 Short talks

16:00 An alternative bulk construction by the flow equation

We propose a new method to construct the bulk theory in $d+1$ dimensions from $d$ dimensional field theory, using a so-called fundamental flow. We show that the conformal symmetry at the boundary is converted to the AdS isometry in the bulk even at the quantum level. We define the metric operators, whose VEV describes the AdS space. We derive the GKP-Witten formula for the bulk scalar field. We finally show that the metric becomes asymptotic AdS in the presence of the scalar primary at the boundary.

Speaker: Sinya Aoki (YITP)

Sinya Aoki_EAJSFS20211123.pdf

16:15 Free energy and defect C-theorem in free theory

We describe conformal defects of p dimensions in a free theory on a d-dimensional flat space as boundary conditions on the conformally flat space Hp+1×Sd−p−1. We classify two types of boundary conditions, Dirichlet type and Neumann type, on the boundary of the subspace Hp+1 which correspond to the types of conformal defects in the free theory. We find Dirichlet boundary conditions always exist while Neumann boundary conditions are allowed only for defects of lower codimensions. Our results match with a recent classification of the non-monodromy defects, showing Neumann boundary conditions are associated with non-trivial defects. We check this observation by calculating the difference of the free energies on Hp+1×Sd−p−1 between Dirichlet and Neumann boundary conditions. We also examine the defect RG flows from Neumann to Dirichlet boundary conditions and provide more support for a conjectured C-theorem in defect CFTs.

Speaker: Yoshiki Sato (Tohoku U)

yoshiki_sato_slide.pdf

17:00 → 17:30 FZZT branes in JT gravity and topological gravity

Speaker: Kazumi Okuyama (Shinshu U)

okuyama.pdf

17:30 → 18:00 3D rank 0 N=4 SCFTs and Non-unitary TQFTs

Speaker: Dongmin Gang (Seoul National U)

Dongmin Gang_EastAsia-2021.pdf

Wednesday, 24 November

09:30 → 10:00 Emergent Supersymmetry on the Edges

Speaker: Sungjay Lee (KIAS)

10:00 → 10:30 What happens when conifold transitions occur at the conifold singularities associated with matter generation in F-theory?

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.

Speaker: Shun'ya Mizoguchi (KEK)

10:30 → 11:00 Coffee Break

11:00 → 11:30 Short talks

11:00 Nonvanishing finite scalar mass in flux compactification

We study possibilities to realize a nonvanishing finite Wilson line (WL) scalar mass in flux compactification. Generalizing loop integrals in the quantum correction to WL mass at one-loop, we derive the conditions for the loop integrals and mode sums in one-loop corrections to WL scalar mass to be finite. We further guess and classify the four-point and three-point interaction terms satisfying these conditions. As an illustration, the nonvanishing finite WL scalar mass is explicitly shown in a six dimensional scalar QED by diagrammatic computation and effective potential analysis. This is the first example of finite WL scalar mass in flux compactification.

Speaker: Takuya Hirose (Osaka City U)

Takuya Hirose_finite(11.24).pdf

11:15 Target space duality of non-supersymmetric string theory

The target space duality of string theory without spacetime supersymmetry, which is constructed by splitting the Narain lattice by a shift-vector with order 2, is investigated. We show that the duality symmetry of such a model is obtained by imposing a congruence condition on $O\left(d_{L},d_{R},\mathbb{Z}\right) $, that is, the non-supersymmetric string model is invariant under a congruence subgroup of $O\left(d_{L},d_{R},\mathbb{Z}\right)$.

Speaker: Sota Nakajima (Osaka City U)

11:30 → 12:00 Digital quantum simulation of the Schwinger model with topological term

Speaker: Masazumi Honda (YITP)

Thursday, 25 November

09:30 → 10:00 5d/6d Wilson loops from blowups

Speaker: Hee-Cheol Kim (POSTECH)

10:00 → 10:30 Gravitational Positivity Bounds and the Standard Model

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.

Speaker: Toshifumi Noumi (Kobe U)

Noumi.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 M2-branes & Quantum Curves

Speaker: Sanefumi Moriyama (Osaka City U)

211125Moriyama.pdf

11:30 → 12:00 Short talks

11:30 Basis decompositions of genus-one string integrals

One-loop scattering amplitudes in string theories involve configuration-space integrals over genus-one surfaces with coefficients of Kronecker-Eisenstein series in the integrand. A conjectural basis of integrands under Fay identities and integration by parts was recently constructed out of chains of Kronecker-Eisenstein series. In this work, we decompose a variety of more general genus-one integrands into the conjectural chain basis. The explicit form of the expansion coefficients is worked out for infinite families of cases where the Kronecker-Eisenstein series form loops. Our results can be used to simplify multiparticle scattering amplitudes in supersymmetric, heterotic and bosonic string theories. The multitude of basis reductions in this work strongly validate the recently proposed chain basis.

Speaker: Yong Zhang (Perimeter institute)

EAJS 2021 Yong Zhang.pdf

11:45 Worldsheet Variables for Cluster Configuration Spaces

We introduce worldsheet variables for a certain moduli space associated with a Dynkin diagram of finite type. The construction is based on gluing a pair of A-type quivers. We find new nonlinear factors that characterize such spaces as hypersurface arrangement complement. We study various topological properties using a finite-field method and propose conjectures about quasi-polynomial point count, dimensions of cohomology, and Euler characteristics for the Dn space up to n=10. These new variables have applications for string integrals, cluster alphabets, etc.

Speaker: Peng Zhao (Institute of Theoretical Physics, Chinese Academy of Sciences)

Peng Zhao_EAJSTalk_v2.pdf

12:00 → 12:30 Conference Photo

12:30 → 14:00 Lunch Break

14:00 → 14:30 Bounds on gravitational S matrix

Speaker: Yu-tin Huang (National Taiwan U)

14:30 → 15:00 Machine Learning Exploration of Continuous Symmetries in Physical Systems

Speaker: Heng-Yu Chen (National Taiwan U)

15:00 → 15:30 Coffee Break

15:30 → 16:00 Anisotropic Holography

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.

Speaker: Dimitrios Giataganas (National Sun Yat-sen U)

Dimitrios Giataganas_osaka_25_11_21_v1.pdf

16:00 → 16:15 Short talks

16:00 Complex Langevin studies of the emergent space-time in the type IIB matrix model

We perform numerical studies of the type IIB matrix model, which was proposed as a nonperturbative formulation of superstring theory in 1996. The complex Langevin method is used in order to overcome the sign problem, which occurs in applying Monte Carlo methods. In particular, we investigate how the signature of the space-time is determined dynamically in this model, and discuss the possibility of the emergence of the (3+1)D expanding universe.

Speaker: Kohta Hatakeyama (KEK)

16:15 → 16:45 Coffee Break

16:45 → 18:00 Poster Session

16:45 Hawking radiation from squashed Kaluza-Klein black holes with quantum gravity effects

We study the Hawking radiation from the five-dimensional charged static squashed Kaluza-Klein black hole by the tunneling of charged fermions and charged scalar particles, including the phenomenological quantum gravity effects predicted by the generalized uncertainty principle with the minimal measurable length. We derive corrections of the Hawking temperature to general relativity, which are related to the energy of the emitted particle, the size of the compact extra dimension, the charge of the black hole and the existence of the minimal length in the squashed Kaluza-Klein geometry. We show that the quantum gravity effect may slow down the increase of the Hawking temperature due to the radiation, which may lead to the thermodynamic stable remnant of the order of the Planck mass after the evaporation of the squashed Kaluza-Klein black hole. We also find that the sparsity of the Hawking radiation may become infinite when the mass of the squashed Kaluza-Klein black hole approaches its remnant mass.

Speaker: Ken Matsuno (Osaka City University)

16:45 Higher derivative extension of the functional renormalization group

We study higher derivative extension of the functional renormalization group (FRG).We consider the general form of the FRG equations for a scalar field that include higher functional derivatives with respect to the field. We show that the epsilon expansion around the Wilson-Fisher fixed point is indeed reproduced by the local potential approximation of the general FRG equations.

Speaker: Gota Tanaka (Shizuoka University)

16:45 Holographic index calculation for Argyres-Douglas and Minahan-Nemeschansky theories

We calculate the superconformal indices of the N=2 superconformal field theories realized on N coincident D3-branes in 7-brane backgrounds with constant axiodilaton via the AdS/CFT correspondence. We include the finite-N corrections as the contribution of D3-branes wrapped around 3-cycles in the internal space. We take only single-wrapping contributions into account for simplicity. We also determine the orders of the next-to-leading corrections which we do not calculate. The orders are relatively high, and we obtain many trustable terms. We give the results for N=1,2,3 explicitly, and find nice agreement with known results.
Reference: arXiv:2110.14897

Speaker: Shuichi Murayama (Tokyo Institute of Technology)

16:45 Non-split singularities and conifold transitions in F-theory

In F-theory, if a fiber type of an elliptic fibration involves a condition that requires an exceptional curve to split into two irreducible components, it is called “split” or “non-split” type depending on whether it is globally possible or not. In the latter case, the gauge symmetry is reduced to a non-simply-laced Lie algebra due to monodromy. We show that the transition from a split to a non-split model is, except in certain exceptional cases, a conifold transition from the resolved to the deformed side, associated with the conifold singularities emerging at the codimension-two loci where the codimension-one singularity is enhanced to $D_{2k+2} (k \geq 1)$ or $E_7$. This clarifies the origin of non-local matter in the non-split case, which has been a mystery for many years.
Reference: arXiv:2108.10136 [hep-th], 2008.09272 [hep-th]

Speaker: Rinto Kuramochi (SOKENDAI/KEK)

Friday, 26 November

09:30 → 10:00 Compactness, Finiteness, and the Swampland

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.

Speaker: Yuta Hamada (Harvard)

10:00 → 10:30 Topological pseudo entropy

Speaker: Tatsuma Nishioka (YITP)

Nishioka_Topological_pseudo_entropy.pdf

10:30 → 11:00 Coffee Break

11:00 → 11:30 Short talks

11:00 Entanglement entropy in Schwarzschild spacetime

Recently, it is proposed that the Hawking radiation contains the information of a region inside the horizon called islands. In the calculation of the entanglement entropy of the Hawking radiation, the dominant contribution comes from the configuration with wormholes between replica geometries. Thus, the entanglement entropy of the Hawking radiation effectively includes the contribution from the island. In this talk, I will discuss the entanglement entropy in the Schwarzschild spacetime, and its relation to the vacuum state of matter fields.

Speaker: Yoshinori Matsuo (Kyoto U)

matsuo.pdf

11:15 Entanglement entropy in interacting field theories

Entanglement entropy (EE) in field theory has been discussed as a measure for quantum entanglement between spatially separated regions. While there are a lot of studies on EE in CFT and free theories, EE in general interacting field theories is of interest in an attempt to associate the effect of the entanglement with low-energy physics. In this talk, I introduce our study on EE in interacting field theories with a subregion of a half space. There, some contributions to EE can be expressed in terms of renormalized correlators of fundamental and composite operators. Moreover, by combining the result with the notion of the Wilsonian RG, we discuss the possibility that EE relevant to low-energy effective theories consists only of those contributions.
This talk is based on 2103.05303, 2105.02598, 2105.14834 and our recent work in progress.

Speaker: Katsuta Sakai (KEK)

EAJS20211126_KatsutaSakai.pdf

11:30 → 12:00 Causal Shadow and modular flow in AdS/CFT: the degenerate case

Speaker: Huajia Wang (KITP)

12:00 → 13:30 Lunch Break

13:30 → 14:00 Defect Extremal Surface and Partial Reduction

Speaker: Yang Zhou (Fudan U)

14:00 → 14:30 Short talks

14:00 Target space entanglement in quantum mechanics of fermions and matrices

I will introduce the notion of target space entanglement. Quantum entanglement is closely related to the structure of spacetime in quantum gravity. For quantum field theories or statistical models, we usually consider the base space entanglement. However, target space instead of base space sometimes directly connects to our spacetime, for example, perturbative string theories. We thus need target space entanglement. To define the target space entanglement, we have to generalize the definition of the conventional entanglement entropy. I will explain this generalization and apply it to the first quantized particles, in particular, fermions.

Speaker: Sotaro Sugishita (Nagoya U)

Sotaro Sugishita_EAJS_target_EE.pdf

14:15 Quantum information metric in the gauge/gravity correspondence

We study how information geometry is described by bulk geometry in the gauge/gravity correspondence. We consider a quantum information metric that measures the distance between the ground states of two field theories, where one is obtained by perturbing the other. We find a universal formula that represents the quantum information metric in terms of back reaction to the bulk geometry. This talk is based on JHEP 06 (2020) 107 (arXiv:2002.11365) and a forthcoming paper.

Speaker: Kazushi Yamashiro (Shizuoka University)

14:30 → 15:00 Coffee Break

15:00 → 15:30 Kramers-Wannier-like duality defects in (3 + 1)d gauge theories

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.

Speaker: Kantaro Ohmori (U of Toyo)

15:30 → 16:00 A BMS-invariant free scalar model

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.

Speaker: Wei Song (Tsinghua U)

Wei Song-BMS-scalar.pdf

16:00 → 16:15 Short talks

16:00 Ginzburg-Landau effective action for a fluctuating holographic superconductor

Under holographic prescription for Schwinger-Keldysh closed time contour for non-equilibrium system, we consider fluctuation effect of the order parameter in a holographic superconductor model. Near the critical point, we derive the time-dependent Ginzburg-Landau effective action governing dynamics of the fluctuating order parameter. In a semi-analytical approach, the time-dependent Ginzburg-Landau action is computed up to quartic order of the fluctuating order parameter, and first order in time derivative.

Speaker: Mitsutoshi Fujita (Sun Yat-Sen University)

presen_EAJS_Fujita.pdf

16:15 → 16:45 Coffee Break

16:45 → 17:00 Short talks

16:45 Holographic $\beta$ function in de Sitter space

We investigate infrared logarithms in inflationary Universe from holographic perspective. We derive gravitational Fokker-Planck and Langevin equations to investigate the time evolution of the de Sitter entropy $S=\pi/G_N H^2(t)$. $H(t)$ is the time dependent effective Hubble parameter and $G_N$ is the Newton's constant. Our approach focuses on the conformal modes to respect local Lorentz symmetry. In term of the curvature perturbations , it is shown to be consistent with $\delta N$ formalism. Under the Gaussian approximation, we obtain the dynamical $\beta$ function of $g=1/S$. The dimensionless gravitational coupling $g$ is asymptotically free toward the future. It also possesses the ultraviolet fixed point indicating that the Universe begun with the de Sitter expansion at the Planck scale with $\epsilon=0$. We further interpret inflationary Universes as the UV complete composite states. Since our analysis is trustable for small $g$, our conclusion is that inflationary universe is consistent in the semiclassical regime.

Speaker: Yoshihisa Kitazawa (KEK)

Yoshihisa Kitazawa_Osaka2021.pdf

17:00 → 17:30 Heavy-Heavy-Light Three-Point Functions from D-branes Revisited

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.

Speaker: Jun-Bao Wu (Tianjin University)

Junbao Wu-EAJW.pdf

17:30 → 18:00 Effective Theory Breaks Down at Scrambling Time

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.

Speaker: Pei-Ming Ho (National Taiwan U)

18:00 → 18:15 Closing

18:00 Closing

Satoshi Iso (KEK) and Kimyeong Lee (KIAS)