KEK Theory Workshop 2021

Session

Short talk

7 Dec 2021, 14:00

Online (Zoom)

Conveners

Short talk: Hikaru Uchida (Hokkaido U.) "Anomaly structure of finite discrete symmetries"

• Yutaka Sakamura (KEK)

Short talk: Tetsutaro Higaki (Keio U.) "New 4D EFT from 10D non-Abelian DBI action in magnetic compactifications"

• Yutaka Sakamura (KEK)

Short talk: Takuya Hirose (Osaka City U.) "Nonvanishing finite scalar mass in flux compactification"

• Yutaka Sakamura (KEK)

Short talk: Ryo Yokokura (KEK) "Topological axion electrodynamics and 4-group symmetry"

• Yutaka Sakamura (KEK)

Short talk: Hiroyuki Kitamoto (YITP) "Semiclassical analysis of axion-assisted and axion-driven pair production"

• Kiyoharu Kawana (SNU)

Short talk: Yugo Abe (Miyakonojo KOSEN) "Perturbative S-matrix unitarity（S† S＝１）in R^2_{μν} gravity"

• Kiyoharu Kawana (SNU)

Short talk: Takahiro Terada (IBS) "Constrained Superfields in Dynamical Background"

• Kiyoharu Kawana (SNU)

Short talk: Osmin Lacombe (YITP) "Hybrid inflation and waterfall field in string theory from D7-branes"

• Satoshi Iso (KEK)

Short talk: Hajime Otsuka (IBS) "Small flux superpotential in F-theory compactifications"

• Kazunobu Maruyoshi (Seikei U.)

Short talk: Rinto Kuramochi (SOKENDAI) "Non-split singularities and conifold transitions in F-theory"

• Kazunobu Maruyoshi (Seikei U.)

Short talk: Shuichi Murayama (Tokyo Inst. of Tech.) "Holographic index calculation for Argyres-Douglas and Minahan-Nemeschansky theories"

• Kazunobu Maruyoshi (Seikei U.)

Short talk: Katsuta Sakai (KEK) "Entanglement entropy and two-point functions of operators"

• Takeshi Morita (Shizuoka U.)

Short talk: Shoichi Kawamoto (NTHU) "Momentum-space entanglement in scalar field theory on noncommutative spaces"

• Takeshi Morita (Shizuoka U.)

Short talk: Yasuhiro Sekino (Takushoku U.) "Rotating strings and particles in AdS: Holography at weak gauge coupling and without conformal symmetry"

• Takeshi Morita (Shizuoka U.)

Short talk: Ken Kikuchi (YMSC) "Symmetry enhancement in RCFT"

• Takeshi Morita (Shizuoka U.)

Short talk: Mitsuyo Suzuki (Osaka City U.) "UV divergent structure of supersymmetric gradient flow in N = 1 SQCD"

• Katsuta Sakai (KEK)

Short talk: Junichi Haruna (Kyoto U.) "Fixed Point Structure of Gradient Flow Exact Renormalization Group"

• Katsuta Sakai (KEK)

Short talk: Gota Tanaka (Shizuoka U.) "Higher derivative extension of the functional renormalization group"

• Katsuta Sakai (KEK)

Short talk: Hidenori Fukaya (Osaka U.) "What is chiral susceptibility probing?"

• Shinsuke Nishigaki (Shimane U.)

Short talk: Shoto Aoki (Osaka U.) "Chiral fermion on curved domain-wall"

• Shinsuke Nishigaki (Shimane U.)

Short talk: Akira Matsumoto (SOKENDAI) "Complex Langevin simulation of 4D SU(2) gauge theory with a theta term"

• Shinsuke Nishigaki (Shimane U.)

Short talk: Atis Yosprakob (SOKENDAI) "Tensor renormalization group and the volume independence in 2D U(N) and SU(N) gauge theories"

• Shinsuke Nishigaki (Shimane U.)

Short talk: Naoki Fukushima (Chiba U.) "Color confinement due to restoration of the residual local gauge symmetry"

• Asato Tsuchiya (Shizuoka U.)

Short talk: Yusuke Kimura (KEK) "4D N = 1 SCFTs on S-folds with T-branes"

• Asato Tsuchiya (Shizuoka U.)

Short talk: Kohta Hatakeyama (KEK) "Signature change of the space-time in the type IIB matrix model"

• Asato Tsuchiya (Shizuoka U.)

Short talk: Matsuo Sato (Hirosaki U.) "Perturbative Strings on Various Curved Backgrounds from String Geometry Theory"

• Asato Tsuchiya (Shizuoka U.)

23. Anomaly structure of finite discrete symmetries

Mr Hikaru Uchida (Hokkaido University)

07/12/2021, 14:00

Finite discrete symmetries are attractive especially for flavor symmetry of quarks and leptons. However, some classical symmetries can be broken by quantum anomaly effects. I will discuss anomaly free and anomalous structure of a finite discrete group $G$ generally.

7. New 4D EFT from 10D non-Abelian DBI action in magnetic compactifications

Prof. Tetsutaro Higaki (Keio University)

07/12/2021, 14:20

We study a systematic derivation of four dimensional N = 1 supersymmetric effective theory
(EFT) from ten dimensional non-Abelian Dirac-Born-Infeld (DBI) action compactified on
a six dimensional torus with magnetic fluxes on the D9-branes. We find a new type of
matter Kahler metric while gauge kinetic function and superpotential are consistent with
previous studies. For the ten dimensional...

8. Nonvanishing finite scalar mass in flux compactification

Mr Takuya Hirose (Osaka City University)

07/12/2021, 14:40

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...

24. Topological axion electrodynamics and 4-group symmetry

Dr Ryo Yokokura (KEK)

07/12/2021, 15:00

We study higher-form symmetries and a higher group in the low energy limit of a $(3+1)$-dimensional axion electrodynamics with a massive axion and a massive photon. A topological field theory describing topological excitations with the axion-photon coupling, which we call a topological axion electrodynamics, is obtained in the low energy limit. Higher-form symmetries of the topological axion...

12. Semiclassical analysis of axion-assisted and axion-driven pair production

Dr Hiroyuki Kitamoto (Yukawa Institute for Theoretical Physics)

07/12/2021, 16:00

We study the pair production of fermions in a time dependent axion background with and without an electric background. We construct the adiabatic mode functions which incorporate the gauge field and the axion velocity dependence of the dispersion relation. The semiclassical approach using this adiabatic basis shows two types of pair production. One is axion-assisted pair production: the...

1. Perturbative S-matrix unitarity（$S^{†}S=1$）in $R_{\mu \nu }^2$ gravity

Dr Yugo Abe (Miyakonojo KOSEN)

07/12/2021, 16:20

We investigate the relation perturbative unitarity and renormalizablility in quantum gravity. In particle theories point of view, Llewellyn Smith conjectured that renormalizablility and tree-unitarity at high energy give the same conditions for theories. If we apply this conjecture to gravity theory, it is shown that Einstein gravity is not renormalizable and does not hold perturbative...

22. Constrained Superfields in Dynamical Background

Dr Takahiro Terada (Institute for Basic Science)

07/12/2021, 16:40

We study nonlinear realization of supersymmetry in a dynamical/cosmological background in which derivative terms like kinetic terms are finite. Starting from a linearly realized theory, we integrate out heavy modes without neglecting derivative terms to obtain constraints on superfields. Thanks to the supersymmetry breaking contribution by the kinetic energy, the validity of constrained...

35. Hybrid inflation and waterfall field in string theory from D7-branes

Dr Osmin Lacombe (Yukawa Institute for Theoretical Physics)

07/12/2021, 17:40

We present an explicit string realisation of the hybrid inflation scenario within the framework of type IIB flux compactifications in the presence of three magnetised D7-brane stacks. The inflaton is identified with the total internal volume modulus and inflation takes place around a metastable de Sitter vacuum, obtained at the very shallow local minimum of the volume modulus scalar potential....

16. Small flux superpotential in F-theory compactifications

Dr Hajime Otsuka (Institute for Basic Science)

08/12/2021, 11:00

We investigate whether a class of models describing F-theory compactifications admits a specific type of flux vacua with an exponentially small vacuum expectation value of the superpotential, by generalizing a method recently developed in Type IIB flux compactifications. First we clarify that a restricted choice of G4-flux components reduces a general flux superpotential into a simple form,...

13. Non-split singularities and conifold transitions in F-theory

Mr Rinto Kuramochi (SOKENDAI)

08/12/2021, 11:20

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...

15. Holographic index calculation for Argyres-Douglas and Minahan-Nemeschansky theories

Mr Shuichi Murayama (Tokyo Institute of technology)

08/12/2021, 11:40

We calculate the superconformal indices of the $\yen mathcalN=2$ 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...

17. Entanglement entropy and two-point functions of operators

Dr Katsuta Sakai (KEK)

08/12/2021, 14:00

Entanglement entropy (EE) is one of the basic measure of the quantum entanglement between the subsystem we see and the other. In order to establish the relation between such an entanglement and realistic observable, it is inevitable to study EE in general interacting field theory. In this talk, I will present our analysis in the case where the subsystem is a half-space, and give a formula for...

9. Momentum-space entanglement in scalar field theory on noncommutative spaces

Dr Shoichi Kawamoto (National Tsing Hua Universiry)

08/12/2021, 14:20

In this talk, I consider the quantum entanglement in the momentum space for scalar field theory on noncommutative spaces. In an interacting quantum field theory, the degrees of freedom in momentum space show entanglement; it quantifies the correlation between the high/low momentum modes. In noncommutative spaces, it is known that the UV and IR degrees of freedom show a characteristic...

19. Rotating strings and particles in AdS: Holography at weak gauge coupling and without conformal symmetry

Prof. Yasuhiro Sekino (Takushoku University)

08/12/2021, 14:40

We consider gauge/gravity correspondence between maximally supersymmetric Yang-Mills theory in (p+1) dimensions and superstring theory on the near-horizon limit of the Dp-brane solution. The string-frame metric is AdS_{p+1}\times S^{8-p} times a Weyl factor, and there is no conformal symmetry except for p=3. We consider states which have angular momenta in the AdS directions. We first show...

10. Symmetry enhancement in RCFT

Dr Ken Kikuchi (Yau Mathematical Sciences Center)

08/12/2021, 15:00

We propose when and why symmetry enhancements happen in massless renormalization group (RG) flows to two-dimensional rational conformal field theories (RCFTs). We test our proposal against known RG flows from unitary minimal models. We also suggest which sign of the relevant coupling triggers the massless RG flow. The other sign triggers massive RG flows to topological quantum field theories...

20. UV divergent structure of supersymmetric gradient flow in N=1 SQCD

Mr Mitsuyo Suzuki (Osaka City University)

08/12/2021, 16:00

I will discuss perturbation theory of supersymmetric gradient flow in four-dimensional N = 1 SQCD and show one-loop calculations to the flowed fields. In flow theory, the perturbation theory consists of a perturbative expansion of the 4D gauge theory and an iterative expansion of the flow equations. We apply the same technique to SQCD in the Wess-Zumino gauge. Once the boundary theory is...

5. Fixed Point Structure of Gradient Flow Exact Renormalization Group

Mr Junichi Haruna (Kyoto University)

08/12/2021, 16:20

Gradient Flow Exact Renormalization Group (GFERG) is a framework of Exact Renormalization
Group and defines the Wilson action via Gradient Flow equation. We study the fixed
point structure of the GFERG equation associated with the general Gradient Flow equation
for scalar fields and show that it is almost the same as that of the Wilson-Polchinski
(WP) equation. Furthermore, we discuss that...

21. Higher derivative extension of the functional renormalization group

Mr Gota Tanaka (Shizuoka University)

08/12/2021, 16:40

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.

3. What is chiral susceptibility probing?

Prof. Hidenori Fukaya (Osaka University)

09/12/2021, 14:00

In the early days of QCD, the axial U(1) anomaly was considered to trigger the breaking of the SU(2)_L ×SU(2)_R symmetry through topological excitations of gluon fields. However, it has been a challenge for lattice QCD to quantify the effect. In this work, we simulate QCD at high temperatures with the overlap Dirac operator. The exact chiral symmetry enables us to separate the contribution...

2. Chiral fermion on curved domain-wall

Mr Shoto Aoki (Osaka University)

09/12/2021, 14:20

We consider a massive fermion system having a curved domain-wall embedded in a square
lattice. As already reported in condensed matter physics, the massless chiral edge modes
appearing at the domain-wall feel “gravity” through the induced spin connections. In this
work, we embed S^1 and S^2 domain-wall into a Euclidean space and show how the gravity is
detected from the spectrum of the...

14. Complex Langevin simulation of 4D SU(2) gauge theory with a theta term

Mr Akira Matsumoto (SOKENDAI)

09/12/2021, 14:40

The Monte Carlo simulation of the gauge theory with a theta term is extremely difficult due to the sign problem. The complex Langevin method (CLM) is one of the approaches which allow us to avoid the problem. Recently the analytic study of 't Hooft anomaly matching condition predicted some nontrivial phase structures around θ=π. We use CLM to study 4D SU(2) gauge theory with a theta term....

25. Tensor renormalization group and the volume independence in 2D U(N) and SU(N) gauge theories

Mr Atis Yosprakob (SOKENDAI)

09/12/2021, 15:00

The tensor renormalization group method is a promising approach to lattice field theories, which is free from the sign problem unlike standard Monte Carlo methods. In this work, we apply the method to two dimensional U(N) and SU(N) gauge theories, where we propose a practical strategy to restrict the number of representations in the character expansion when constructing the fundamental tensor....

4. Color confinement due to restoration of the residual local gauge symmetry

Mr Naoki Fukushima (Chiba University)

09/12/2021, 16:00

All colored particles including dynamical quarks and gluons are confined if the color confinement
criterion proposed by Kugo and Ojima is satisfied. The criterion was obtained under
the gauge fixing of the Lorenz type. However, it was pointed out that the Kugo-Ojima criterion
breaks down for the Maximal Abelian gauge, which is quite strange in view of the fact
that quark confinement has...

11. 4D N=1 SCFTs on S-folds with T-branes

Dr Yusuke Kimura (KEK)

09/12/2021, 16:20

We discuss four-dimensional (4d) N=1 superconformal field theories (SCFTs) obtained as deformations of 4d N=2 SCFTs on S-folds by tilting 7-branes. Geometric compatibility with the structures of S-folds constrains the forms of T-branes.

6. Signature change of the space-time in the type IIB matrix model

Dr Kohta Hatakeyama (KEK)

09/12/2021, 16:40

We perform numerical studies of the type IIB matrix model, which was proposed as a
nonperturbative formulation of superstring theory in 1996. In our study, we apply the
complex Langevin method in order to overcome the sign problem, which occurs in Monte
Carlo simulations. In particular, we investigate a scenario on how the signature of space-time
could be determined dynamically in this...

18. Perturbative Strings on Various Curved Backgrounds from String Geometry Theory

Prof. Matsuo Sato (Hirosaki University)

09/12/2021, 17:00

One perturbative string theory is defined on one fixed background. On the other hand, it is necessary that a non-perturbative formulation of string theory includes all the perturbatively stable vacuum and perturbative string theories on various curved backgrounds are derived from the single theory. In this talk, we derive perturbative string theories on various curved backgrounds from the...