YITP Workshop
Strings and Fields 2021

August 23 (Mon) - August 27 (Fri), 2021

Program

Invited talks are in mild orange, Oral talks are in sky blue, Posters are in gray purple.
Length of talks: 60+10 mins for invited talk and 25+5 mins for short talk.
There are parallel sessions for short talks this year, due to large number of requests for short talks.
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Day 1
Invited
Simon Caron-Huot	McGill	Causality constraints and gravity
Effective field theories (EFT) are widely used to parameterize long-distance effects of unknown short-distance dynamics or possible new heavy particles. It is known that EFT parameters are not entirely arbitrary, and must obey positivity constraints if causality and unitarity are satisfied at all scales. We systematically explore those constraints from the perspective of 2 to 2 scattering processes, and show that all EFT parameters in units of the mass threshold M are bounded below and above: causality requires a sharp form of dimensional analysis scaling. Gravity is special since its tree-level energy growth already requires a UV completion; I will describe some model-independent constraints on the graviton’s self-interactions.

Parallel Slot A
Junsei Tokuda	Kobe University	Quantum gravity constraints on scalar potentials from positivity bounds
We study positivity bounds on scalar field theories coupled to gravity by assuming several properties of scattering amplitudes. We find that scalar potentials cannot be arbitrarily flat unless some new physics enters well below the Planck scale. An upper bound on the scale of new physics is found to be determined by the self-energy. Our result provides a quantitative swampland condition for scalar potentials. Based on 2105.01436
Katsuki Aoki	YITP, Kyoto University	Is the Standard Model in the Swampland?
We study compatibility of the Standard Model of particle physics and General Relativity by means of gravitational positivity bounds, which provide a necessary condition for a low-energy gravitational theory to be UV completable within the weakly coupled regime of gravity. In particular, we identify the cutoff scale of the Standard Model coupled to gravity by studying consistency of light-by-light scattering. While the precise value depends on details of the Pomeron effects in QCD, the cutoff scale reads $10^{16}$GeV if the single-Pomeron exchange picture works well up to this scale. We also demonstrate that the cutoff scale is lowered to $10^{13}$GeV if we consider the electroweak theory without the QCD sector. Based on 2104.09682
Parallel Slot B
Matsuo Sato	Hirosaki University	Backgrounds of All the Five Ten-dimensional Supergravities from String Geometry Theory
String geometry theory is a candidate of the non-perturbative formulation of string theory. In case of a perturbative string theory, string backgrounds are treated as external fields. Whereas a non-perturbative string theory needs to be able to describe dynamics of the string backgrounds in order to determine a string vacuum. In this talk, we show that all the type IIA, IIB, SO(32) type I, and SO(32) and $E_8 \times E_8$ heterotic supergravity backgrounds are embedded in configurations of the fields of a single string geometry model. Especially, we show that the configurations satisfy the equations of motion of the string geometry model in $\alpha' \to 0$ if and only if the embedded string backgrounds satisfy the equations of motion of the corresponding five supergravities, respectively. This means that classical dynamics of the string backgrounds are described as a part of classical dynamics in string geometry theory. This fact supports the conjecture that string geometry theory is a non-perturbative formulation of string theory. Furthermore, we define an energy of the configurations in the string geometry model because they do not depend on the string geometry time. A string background can be determined by minimizing the energy. Based on 2102.12779
Gustavo Arciniega	Universidad Nacional Autónoma de México	A unified geometric description of the Universe: from inflation to late-time acceleration without a cosmological constant
We present a cosmological model arising from a gravitational theory with an infinite tower of higher-order curvature invariants that can reproduce the entire evolution of the Universe: from inflation to late-time acceleration, without invoking a scalar inflaton nor a cosmological constant. The theory is Einsteinian-like. The field equations for a FLRW metric are second-order and can reproduce an acceleration that is in agreement with the SuperNovae data collection. Our results force us to reinterpret the nature of dark energy, becoming a mechanism that is inherited solely from the geometry of spacetime.

Parallel Slot A
Silvia Nagy	Queen Mary University of London	The double copy for asymptotic symmetries
I will describe the construction of a subset of the asymptotic symmetries in gravity from Yang-Mills symmetries via the double copy correspondence. This is based on the study of certain residual symmetries of the self-dual sectors of Yang-Mills and gravity, which additionally gives some interesting connections between perturbative and non-perturbative aspects of the double copy. Finally, we use the DC to describe some symmetries which (to our knowledge) have not yet been presented in the asymptotics literature. Based on 2102.01680
Keisuke Izumi	KMI & Dept. of Math., Nagoya U.	Area bound for surfaces in general relativity
On asymptotically-flat maximal spacelike 3-surfaces, the area of minimal 2-surfaces is suppressed by that of Schwarzschild spacetime. Since, on time-symmetric 3-surface, an apparent horizon becomes a minimal 2-surface, this upper bound must show the maximum of entropy. The inequality expressing it is called Riemannian Penrose inequality. In this talk, the inequality is generalized for surfaces in generic gravitational field where the gravity is moderately strong or even weak. It must be helpful to understand the thermodynamics properties of gravitational theory not relied on black holes. Based on 2101.03860
Parallel Slot B
Oem Trivedi	Ahmedabad University	Swampland conjectures and single field inflation in modified cosmological scenarios
Swampland Conjectures have attracted quite some interest in the Cosmological Community. They have been shown to have wide ranging implications , like Constraints on Inflationary Models, Primordial Black Holes, Dark Energy to name a few. Particularly, their implications on Single Field Inflationary Models in General Relativity Based Cosmology has gathered huge attention. Swampland Conjectures in their usual form have been shown to be incompatible with these kind of Single Field Models, or have been shown to induce severe Fine Tuning in these Inflationary Models for them to be consistent with the Conjectures. In this work, we show that a Large Class of Single Field Inflationary Models can in fact bypass the problems faced by Inflationary Paradigms in GR Based Cosmology. We use the Exact Solution Approach to Inflation for the same purpose and show how String Theoretic Motivations of the Swampland Conjectures can be in perfect symphony with various Single Field Inflationary Models in Modified Cosmological Scenarios. Based on 2008.05474
Maurice van Putten	Sejong University	H0-tension: a whisper of unstable de Sitter by T-duality in the Friedmann scale factor?
H0-tension between the Local Distance Ladder and LambdaCDM increasingly suggests that the latter produces a systematic under-estimate of the Hubble parameter by the assumed stable de Sitter state in the future. This assumption may be false, anticipated by the Swampland conjectures. We present a theory of cosmological evolution with unstable de Sitter (UdS) in the future, which otherwise effectively reduces to LambdaCDM in the past. It derives from a non-local correction to the propagator in cosmological spacetime due to the Hubble horizon. It renders de Sitter unstable, identified with a T-duality invariant D(a)+D(kappa)=2 in the Friedmann scale factor a, where D(a)=-q is curvature given by the deceleration parameter q in LambdaCDM and kappa=1/a. In confrontation with observations, it quantitatively explains H0-tension by a turning point in H(z) around redshift zero, consistent with the age of the Universe measured independently by the ages of globular clusters. (Based on van Putten, 2020, MNRAS Lett., 491, L6).

Parallel Slot A
Mitsutoshi Fujita	Sun Yat-Sen University	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.
Ryota Watanabe	Osaka University	Bulk reconstruction of metrics inside black holes by complexity
We provide a formula to reconstruct bulk spacetime metrics inside blackholes by the time dependence of complexity in the dual quantum field theory, based on thecomplexity=volume (CV) conjecture in the holographic duality. Based on 2103.13186
Parallel Slot B
Hayato Kanno	Yukawa Institute for Theroretical Physics, Kyoto University	Anomaly and Superconnection
We study anomalies of fermion with spacetime dependent mass. We calculate anomalies, which associate with the $U(N)\times U(N)$ chiral symmetry for even dimension and $U(N)$ flavor symmetry for odd dimension, using Fujikawa method. We show these anomalies can be written by superconnection. In particular, we focus on vector-like $U(1)$ part of the anomalies in this talk.These results can be applied to some general systems with interfaces and boundaries. They are also useful to some index theorems, such as APS index theorem. In the last part of this talk, the relation between this anomaly and string theory is discussed.This talk is based on [arXiv:2106.01591], work with Shigeki Sugimoto. Based on 2106.01519
Ryo Yokokura	KEK	Global 4-group symmetry of axion electrodynamics in a gapped phase
We study higher-form symmetries in (3+1)-dimensional axion electrodynamics where the axion and photon are massive. In the low-energy limit, we establish a topological field theory which describes topological excitations with an axion-photon coupling. The higher-form symmetries are specified in the topological field theory. By using intersections of symmetry generators, we argue that the worldvolume of an axionic domain wall is topologically ordered, and we discuss the underlying 4-group structure.
Tadashi Okazaki	Durham University	Fermi-gas correlators of ADHM theory and triality symmetry
We analytically study the Fermi-gas formulation of sphere correlation functions of the Coulomb branch operators for 3d $\mathcal{N} = 4$ ADHM theory with a gauge group $U(N)$, an adjoint hypermultiplet and $l$ hypermultiplets which can describe a stack of $N$ M2-branes at $A_{l−1}$ singularities. We find that the leading coefficients of the perturbative grand canonical correlation functions are invariant under a hidden triality symmetry conjectured from the twisted M-theory. The triality symmetry also helps us to fix the next-to-leading corrections analytically.

Poster Session
1: Shoto Aoki	Osaka University	Chiral fermion on curved domain-wall
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 Euclidean space and show how the gravity is detected from the spectrum of the Dirac operator. We also discuss how we can understand gravitational anomaly inflow and index theorem with nontrivial curvature of the domain-wall.
2: Yui Hayashi	Chiba University	Reconstructing propagators of confined particles in the presence of complex singularities
Propagators of confined particles, especially the Landau-gauge gluon propagator, may have complex singularities as suggested by recent numerical works as well as several theoretical models, e.g., motivated by the Gribov problem. In this presentation, we discuss formal aspects of propagators with complex singularities in reconstructing Minkowski propagators starting from Euclidean propagators by the analytic continuation. We rigorously derive properties to be satisfied by the relevant propagators in the presence of complex singularities. As a result, the analytically-continued Wightman function is holomorphic in the tube, and the Lorentz symmetry and locality are kept valid. In contrast, the reconstructed Wightman function violates the temperedness and the positivity condition. Finally, we consider implications on a possible quantum mechanical interpretation and confinement mechanism. Based on 2105.07487
3: Takuya Hirose	Osaka City University	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. Based on 2104.01779
4: Shoichi Kawamoto	National Tsing Hua University	Quantum entanglement of accelerated particles and holographic dual
A pair of entangled particles in strongly coupled gas is analyzed by use of the holographic method. When the particles are in uniform acceleration, I analyze the fluctuations in the gravity side. Based on the analysis, I study the time evolution of the entanglement of these particles from the holographic point of view.
5: Isao Kishimoto	Sanyo-Onoda City University	On numerical universal solutions in a-gauge in open string field theory
We construct numerical solutions in Asano-Kato's $a$-gauge in open string field theory, which correspond to Kudrna-Schnabl's double brane and ghost brane solutions as well as the tachyon vacuum solution in the Siegel gauge. We evaluate gauge invariants (energy and gauge invariant overlap) for obtained solutions up to the truncation level 20. Except for those of the tachyon vacuum, we find that they are relatively unstable for various values of $a$, unlike the case of the Siegel gauge ($a=0$), where we investigated them around Takahashi-Tanimoto's identity-based solution in the previous work [Kishimoto-Takahashi(2020)].
6: Takayasu Kondo	Tokyo Institute of Technology	WKB periods for higher order ODE and TBA equations
We study the WKB periods for the $(r+1)$-th order ordinary differential equation (ODE) which is obtained by the conformal limit of the linear problem associated with the $A^{(1)}_r$ affine Toda field equation. We compute the quantum corrections by using the Picard-Fuchs operators. The ODE/IM correspondence provides a relation between the Wronskians of the solutions and the Y-functions which satisfy the thermodynamic Bethe ansatz (TBA) equation related to the Lie algebra $A_r$. For the quadratic potential, we propose a formula to show the equivalence between the logarithm of the Y-function and the WKB period, which is confirmed by solving the TBA equation numerically. Based on 2104.13680
7: Ken Matsuno	Osaka City University Advanced Mathematical Institute	Hawking radiation from squashed Kaluza-Klein black holes with a generalized uncertainty principle
We consider the Hawking radiation by the tunneling of charged fermions and charged scalar particles from the five-dimensional charged static squashed Kaluza-Klein black hole based on the generalized uncertainty principle with a 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 extra dimension, the charge of the black hole and the quantum effect predicted by the generalized uncertainty principle. It is shown that the quantum correction may slow down the increase of the Hawking temperature, 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. Based on 2104.00891
8: Kaoru Miyamoto	Kitasato University	Three-dimensional generalization of vortex equation.
The Taubes equation is a two-dimensional vortex equation on hyperbolic plane, whose solutions are solved exactly. This equation has a completely geometrical interpretation developed by Baptista and the construction can be generalized to three-dimensional setup. In this work, we propose three-dimensional version of the Taubes equation constructed by analogy of Baptista’s method and explore its solutions. (Joint work with A. Nakamula)
9: Akihiro Miyata	The University of Tokyo, Komaba	Evaporation of black holes in flat space entangled with an auxiliary universe
We study a thermofield double type entangled state on two disjoint universes A and B, where one of the universes is asymptotically flat containing a black hole. As we increase the entanglement temperature, this black hole receives back-reaction from the stress energy tensor of the state. This results in lengthening of the wormhole region in the black hole interior, and decreasing of its horizon area, both of which are key features of an evaporating black hole. We then compute the entanglement entropy on the universe A through the island formula, and argue that it naturally follows the Page curve of an evaporating black hole in flat space. We also study the effects of local operations in the gravitating universe with the black hole. We find that they accelerate the evaporation of the black hole, therefore disrupt the entanglement between two universes. Furthermore, we observe that depending on whether the operation can be regarded as an LOCC or not, the behavior of the entanglement entropy changes. In particular, when the operation is made neither in the entanglement wedge of the radiation system or that of the black hole, the transition between the island phase and the no-island phase can happen multiple times. Based on 2104.00183
10: Takeshi Morita	Shizuoka University	Numerical bootstrap method for quantum physics
We apply numerical bootstrap method to quantum mechanics and matrix models. We show that this method may be very powerful in large-N gauge theories for several quantities. On the other hand, this method has some serious problems in several situations. In this poster, I will introduce these advantages and disadvantages of the bootstrap method.
11: Yuta Nasuda	Tokyo University of Science	Non-exactness of SWKB quantization condition and the higher order corrections
The SWKB quantization condition is an exact quantization condition for the class of conventional shape-invariant potentials.In this poster, we focus on the condition for other classes of solvable quantum-mechanical systems: multi-indexed systems, Krein--Adler systems, and conditionally exactly solvable systems.The condition equation is not exactly but approximately satisfied.We also discuss higher order corrections of the SWKB condition for those cases and the connection with some features of the quantum-mechanical systems. Based on 2004.04927
12: Nitika Sachdeva	Bhagwan Parshuram Institute of Technology, Guru Gobind Singh Indraprastha University	Binomial coefficients and Arithmetic Progression in an Alternating Series with its interpretation in Vector Space
A series is defined using terms of arithmetic sequence taken along with binomial coefficients nCr. By deriving it in all the subsequent sections of Pascal’s hexagon, the series is extended for nCr where n, r belong to R. Further, it is analyzed in a vector space and is found to be a subspace of it. The series is studied as a scalar product of three-dimensional vectors where some of the findings are generalized for n-dimensions.
13: Yoshiki Sato	NCTS	Complexity in a moving mirror model
The moving mirror model is a simple CFT model and mimics a black hole. If the moving mirror model is a holographic CFT, we can apply the AdS/CFT correspondence. In this setup, we study the subregion complexity motivated by the fact that the complexity can detect a late time behaviour of the black hole in contrast to the entanglement entropy.
14: Yotaro Sato	Kavli IPMU	Monodromies and Anomalies in N=2 Heterotic String
The cancellation mechanism of global anomalies in string theories is hardly known in terms of the internal CFT. This is one approach to this problem using N=2 supersymmetry.Heterotic compactifications with N=2 supersymmetry have almost the same story as Seiberg-Witten theory for gauge theories. We showed that the monodromy transformations are realized by lattice isometries of the internal lattice CFT, and the unphysicalness of the monodromy transformations is equivalent to the cancellation of Witten anomaly.
15: Lakhdar Sek	University of biskra	2+1 Dimensional relativistic oscillator under a uniform magnetic field in noncommutative space
In this paper, we study the thermodynamic properties of KG oscillator under the effect of an external magnetic field in noncommutative space, where the exact energy eigenvalues and normalized wave function are obtained analytically.
16: Taichi Shimizu	Tokyo University of Science	Analysis on longevity of Q-balls by dynamical simulations
We study the time evolution of Q-balls in the gravity-mediated SUSY breaking model, in terms of long-term dynamical simulations with the symplectic integrator. We examine whole life of Q-balls such as emergence, formation and decay or collapse of the each ball. As a result, we observe that the Q-balls are metastable and have a finite longevity, though they possess the conserved $U(1)$ charge. We discuss property of an effective interaction concerning growth or decay of the Q-ball formulation and how the longevity is attained with it.
17: Shreya Shukla	University of California, Irvine	Metaplectic flavor symmetries from magnetized tori
We revisit the flavor symmetries arising from compactifications on tori with magnetic background fluxes. Using Euler's Theorem, it is possible derive closed form analytic expressions for the Yukawa couplings that are valid for arbitrary flux parameters. Furthermore, we show that the modular transformations for even and odd units of magnetic flux, M, and show that they give rise to finite metaplectic groups the order of which is determined by the least common multiple of the number of zero-mode flavors involved. Unlike in models in which modular flavor symmetries are postulated, in this approach they derive from an underlying torus. This allows us to retain control over parameters, such as those governing the kinetic terms, that are free in the bottom-up approach, thus leading to an increased predictivity. Based on 2102.11286
18: Mitsuyo Suzuki	Osaka City University	UV-finiteness of supersymmetric gradient flow in N=1 SQCD
I will discuss perturbation theory of supersymmetric gradient flow in 4D N = 1 SQCD. The perturbation theory consists of a perturbative expansion of 4D SQCD and an iterative expansion of the flow equation. In particular, I will discuss the 1-loop calculations of the flowed correlation functions.
19: Maki Takeuchi	Kobe University	Proof of index theorem on $T^2/Z_2$ orbifold with magnetic flux
We obtained a general formula that gives the number of chiral zero modes on $T^2/Z_N$ orbifold with a magnetic flux background. However it is not clear whether this formula is an index theorem or not. In the case of $T^2/Z_2$ orbifold with a magnetic flux background, we will directly check this formula by deriving it from the trace formula.
20: Takanao Tsuyuki	Kogakuin University	Minkowski spacetime and non-Ricci-flat compactification in heterotic supergravity
We compactify the ten-dimensional spacetime in heterotic supergravity leaving four-dimensional Minkowski spacetime. We search for non-supersymmetric, non-Ricci-flat solutions of the equations of motion and the condition for anomaly cancellation. By assuming that the extra-dimensional spaces are products of 2-manifolds, three types of solutions are found. They are $S^2\times T^2 \times H^2/\Gamma$, $S^2\times H^2/\Gamma \times H^2/\Gamma$ and $S^2\times S^2 \times H^2/\Gamma$, where $H^2/\Gamma$ denotes a compact hyperbolic manifold. The metrics can be written explicitly for all of them, and they can be applied for phenomenology. Based on 2106.03625
21: Taizan Watari	Kavli IPMU	W=0 Complex Structure Moduli Stabilization CM-type K3 x K3 Orbifolds
Flux compactification of Type IIB string or F-theory generically leaves vacuum energy of order $M_{Pl}^4$ and gravitino mass of order $M_{Pl}$, where $M_{Pl}$ is the Planck scale. Whether there is a mechanism or condition that yields small value of those in flux compactification (W=0) is an important input on such issues as volume stabilization, inflation, supersymmetric grand unification and supersymmetric dark matter. $\;$ It is known that W=0 flux is available when the target space has complex structure of CM (complex multiplication) type. We discuss construction of Calabi-Yau 4-folds with CM-type complex structure in the form of K3 x K3 orbifilds, and study consequences in the low-energy physics. $\; $ This presentation is based on a joint work with K. Kanno. Based on 2012.01111
22: Shota Yanai	Tokyo University of Science	Multi-layered $Q$-compactons in a nonlinear sigma model
We study compact $Q$-ball, $Q$-shell solutions in a nonlinear sigma model with target space $\mathbb{C}P^N$. The multi-component-type models with V-shaped potentials possess multi-layered compact $Q$-ball and -shell solutions. We have found the $n$-folded $Q$-ball/-shell, or $n$-layered $Q$-ball/-shell (harboring) solutions. The model possesses solutions with wide variety in their spatial structure. In this presentation, we show some examples and discuss the potential physical applications.

Day 2
Invited
Davide Gaiotto	Perimeter Institute	The giant graviton expansion
I will present a peculiar localization-like formula valid for the superconformal index of many QFTs with holographic duals. It expresses the index as a sum over fixed point contributions associated to giant graviton configurations. Based on 2106.14859

Plenary
Satoshi Yamaguchi	Osaka University	Supersymmetric quantum field theory with exotic symmetry in 3+1 dimensions and fermionic fracton phases
Fracton phases show exotic properties, such as sub-extensive entropy,local particle-like excitation with restricted mobility, and so on.In order to find natural fermionic fracton phases, we exploresupersymmetric quantum field theory with exotic symmetry. We usesuperfield formalism and write down the action of a supersymmetricversion of one of the simplest models with exotic symmetry, the $\varphi$theory in 3+1 dimensions. It contains a large number of ground statesdue to the fermionic higher pole subsystem symmetry. Its residualentropy is proportional to the area instead of the volume. This theoryhas a self-duality similar to that of the $\varphi$ theory. We also write downthe action of a supersymmetric version of a tensor gauge theory, anddiscuss BPS fractons. Based on 2102.04768
Hirotaka Hayashi	Tokai University	6d/5d exceptional gauge theories from web diagrams
We construct novel web diagrams with a trivalent or quadrivalent gluing for various 6d/5d theories from certain Higgsings of 6d conformal matter theories on a circle. The theories realized on the web diagrams include 5d Kaluza-Klein theories from circle compactifications of 6d theories with exceptional gauge groups. The Higgsings also give rise to 5d Kaluza-Klein theories from twisted compactifications of 6d theories. We also compute the Nekrasov partition functions of the theories by applying the topological vertex formalism to the newly obtained web diagrams. Based on 2103.02799

Parallel Slot A
Dongwook Ghim	Korea Institute for Advanced Study	5d BPS quivers and KK towers
This talk will present recent progress in computing (refined) Witten index of BPS quiver for 5d gauge theories, compactified on a circle. With stringy BPS objects in 5d theory being wrapped on the circle, the wall-crossing problem of 4d KK theory can be addressed by N=4 quiver quantum mechanics. However, the fine-tuned superpotential of the latter makes many of the known machinery fail to capture its Witten indices. I will show how the subtlety can be bypassed for a restricted class of BPS quivers. Specifically, the $L^2$ cohomology counting and D0 brane picture will construct neutral KK sectors. Then I will show how to apply Coulomb branch formula to purely electric BPS sectors. Based on 2011.04661
Dmitrii Galakhov	Kavli IPMU	Shifted Quiver Yangians and Representations from BPS Crystals
We introduce a class of new algebras, the shifted quiver Yangians, as the BPS algebras for type IIA string theory on general toric Calabi-Yau three-folds. We construct representations of the shifted quiver Yangian from general subcrystals of the canonical crystal. We derive our results via equivariant localization for supersymmetric quiver quantum mechanics for various framed quivers, where the framings are determined by the shape of the subcrystals. Our results unify many known BPS state counting problems, including open BPS counting, non-compact D4-branes, and wall crossing phenomena, simply as different representations of the shifted quiver Yangians. Furthermore, most of our representations seem to be new, and this suggests the existence of a zoo of BPS state counting problems yet to be studied in detail. Based on 2106.01230
Parallel Slot B
Adrita Chakraborty	Indian Institute of Technology Kharagpur	Study of probe $(m,n)$-string in $AdS_{3}\times S^{3}$ background with mixed flux by using Neumann-Rosochatius integrable model
Being one of the earliest integrable mathematical models , Neumann-Rosochatius (NR) system has occurred to be a valid platform for the study of various string backgrounds having integrable features. In the near horizon limit, an $SL(2,Z)$ transformed bound state solution of Q5 NS5-branes and Q1 fundamental strings, gives rise to $AdS_3 X S^3$ background with mixed three form fluxes having integer charges. $SL(2,Z)$ covariant action for probe $(m,n)$ string in $AdS_3X S^3X T^4$ with mixed three-form fluxes can be described by an integrable deformation of an one-dimensional NR system. We reproduce the rotating and pulsating string profiles in terms of some standard Weierstrass elliptic functions by solving the integrable equations of motion of the deformed NR model. The energy-angular momentum scaling relations obtained with such solutions are observed to be credibly supported by those which are dual to some of the anomalous dimensions in the field theory side of the holography. Based on 2008.05139
Priyadarshini Pandit	Indian Institute of Technology Kharagpur	N Spike D-string in AdS space with mixed flux
We use Dirac-Born-Infeld action to study the spinning D-string in AdS3 background in the presence of both NS-NS and RR fluxes. We compute the scaling relation between the energy (E) and spin (S) in the `long string limit'. The energy of these spiky string is found to be a function of spin with the leading logarithmic behaviour and the scaling relation appears to be independent of the amount of flux present. We further discuss folded D-string solutions in $AdS3$ background with pure NS-NS and R-R fluxes. Based on 2003.08604

Parallel Slot A
Panupong Cheewaphutthisakun	Graduate School of Mathematics, Nagoya University	MacMahon KZ equation for Ding-Iohara-Miki algebra
We derive a generalized Knizhnik-Zamolodchikov equation for the correlation function of the intertwiners of the vector and the MacMahon representations of Ding- Iohara-Miki algebra. These intertwiners are cousins of the refined topological vertex which is regarded as the intertwining operator of the Fock representation. The shift of the spectral parameter of the intertwiners is generated by the operator which is constructed from the universal R matrix. The solutions to the generalized KZ equation are factorized into the ratio of two point functions which are identified with generalizations of the Nekrasov factor for supersymmetric quiver gauge theories. Based on 2101.01420
Marcus Sperling	Tsinghua University, Yau Mathematical Sciences Center	Quantum curves for 6d N=(1,0) theories
The quantisation of the Seiberg-Witten curves of 6d theories compactified on a two-torus leads to difference operators in the class of elliptic quantum curves. In this talk, I will illustrate two examples: firstly, 6d N=(1,0) SU(n) theory with 2n fundamental flavours and, secondly, the 6d E-string theory. For both cases, the quantum curves can be rephrased as eigenvalue equations. The eigenfunctions correspond to codimension 2 defect operators and the eigenvalues are codimension 4 Wilson surfaces wrapping the elliptic curve, respectively.Among others, I will comment on a path-integral derivation of the quantum curve and the relation to integrable models, such as the van Diejen model for the E-string. Based on 2103.16996, 2008.05155
Parallel Slot B
Sunjin Choi	Korea Institute for Advanced Study	Small AdS black holes from Yang-Mills matrix model
We study the large $N$ matrix model for the index of 4d $\mathcal{N}=4$ Yang-Mills theory and its truncations to understand the dual AdS$_5$ black holes. Numerical studies of the truncated models provide insights on the black hole physics, some of which we investigate analytically with the full Yang-Mills matrix model. In particular, we find many branches of saddle points which describe the known black hole solutions. We analytically construct the saddle points dual to the small black holes whose sizes are much smaller than the AdS radius. They include the asymptotically flat BMPV black holes embedded in large AdS with novel thermodynamic instabilities. Based on 2103.01401
Yuki Yokokura	RIKEN, iTHEMS	Universality of Interior Metric of Typical Black Holes
We study the interior metric of a spherical black hole formed adiabatically in a heat bath. As a necessary condition, it must satisfy the trace part of the semi-classical Einstein equation, $G^\mu{}_\mu=8\pi G \langle \psi\| T^\mu{}_\mu\|\psi \rangle$, whose right-hand side for conformal matter fields is given by the 4-dimensional Weyl anomaly. By the consistency with Hawking radiation, the interior solution is uniquely determined except for one parameter as a warped product of $AdS_2$ and $S^2$, with almost Planckian curvature. As a result, a black hole is a dense object with a surface (not a horizon) slightly outside the Schwarzschild radius. Based on 2108.02242

Parallel Slot A
Masataka Koide	Osaka university	Non-invertible duality defects in 4-dimensional pure Z2 gauge theory
In recent years, the extension of the notion of symmetry using the picture of topological defects and its applications have been actively studied. One direction is the so-called category symmetry in 2dimensional spacetime, in which non-invertible topological defects are treated as “symmetry”. For example, Aasen, Fendley, and Mong have constructed topological defects, including noninvertible ones, from duality in a two-dimensional lattice model.We have specifically constructed non-invertible topological defects from duality in 4D lattice pure Z2 gauge theory. In this talk, we will show that such a topological defect exists, and explain that the defect is non-invertible.This work is in collaboration with Y.Nagoya and S.Yamaguchi.
Yuta Nagoya	Osaka university	Topological defect junctions in 4-dimensional pure Z2 gauge theory
Recently, there are active studies on extended concepts of symmetries and its applications. One of the directions is to regard non-invertible topological defects as "symmetry". We explicitly constructed non-invertible duality defects and 1-form center symmetry defects in 4D lattice pure Z2 gauge theory.In this talk, we will describe the junction that occurs where the two defects contact. The duality defect is non-invertible, Unlike the usual symmetry operators, it is not necessary to be invariant under deformations that change the topology. The topological relations are closed for such deformations including 1-form center symmetry defect and junctions. This work is in collaboration with M.koide and S.Yamaguchi.
Parallel Slot B
Chiara Toldo	Amsterdam University	Updates on the search for multicenter AdS black holes from M-theory
We study the properties of the effective potential for various kind of probe branes in background of AdS_4 black holes arising in the homogeneous Sasaki-Einstein_7 truncation of M-theory on Q^{111} and M^{111}. This includes in particular internally wrapped "particle-like" M2 and, upon reduction to type IIA, D6 branes corresponding to baryon operators in the dual Chern Simons theory. We find negative and positive minima of the potential outside the horizon, which respectively signal the possible existence of stable and metastable black hole bound states (multi-center black holes) at fixed temperature and charges in global and four-dimensional asymptotically Anti-de Sitter space. We comment on the relevance of these systems for the holographic description of glassy phases. For the planar case, we also find an instability towards nucleation of spacetime-filling M2 branes. We finally comment on various other aspects of this instability, for instance its relation to the Weak Gravity Conjecture.[to appear, in collaboration with R. Monten]
Antonio Gallerati	Polytechnic of Turin	Instability of supersymmetric black holes via quantum phase transitions
We discuss the instability of special four-dimensional supersymmetric hyperbolic black holes in the canonical ensemble. To this end, we consider an infinite class of N=2 supergravity theories, interpolating between all the single dilaton truncations of the SO(8) gauged N=8 supergravity. Within these models, we study electrically charged solutions of two different kinds: supersymmetric hairy and extremal non-supersymmetric Reissner-Nordström black holes. For suitable choices of the parameters, the non-supersymmetric solution features a lower free-energy than the supersymmetric one in the canonical ensemble.In the absence of additional selection rules, this would imply an instability of the supersymmetric configuration, hinting towards a possible supersymmetry breaking mechanism. Based on 2105.08771

Invited
Kantaro Ohmori	U. Tokyo	Symmetries and Strings of Adjoint QCD2
In this talk, I first introduce the notion of non-invertible symmetries and then describe them in the 1+1-dimensional QCD with adjoint fermions. In particular, we can explain the deconfinement of the theory at the zero temperature when fermions are massless by such symmetries. I will discuss the possible future direction regarding non-invertible symmetries in the last part of the talk. This talk is based on a work co-authored with Z. Komargodski, K. Roumpedakis, and S. Seifnashri. Based on 2008.07567

Day 3
Invited
Leonard Susskind	Stanford	Does the Holographic Principle Apply to de Sitter space, and if so, How?
The question I will explore is whether the Holographic Principle applies to de Sitter space, and if so what do we know about the holographic degrees of freedom and their dynamics?

Plenary
Ugajin Tomonori	Yukawa Institute for Theoretical Physics	Entanglement between two gravitating universes
We study two disjoint universes in an entangled pure state. When only one universe contains gravity, the path integral for the $n^{\text{th}}$ R\'enyi entropy includes a wormhole between the $n$ copies of the gravitating universe, leading to a standard ``island formula'' for entanglement entropy consistent with unitarity of quantum information.When both universes contain gravity, gravitational corrections to this configuration lead to a violation of unitarity. However, the path integral is now dominated by a novel wormhole with $2n$ boundaries connecting replica copies of both universes.The analytic continuation of this contribution involves a quotient by $\mathbb{Z}_n$ replica symmetry, giving a cylinder connecting the two universes.When entanglement is large, this configuration has an effective description as a ``swap wormhole'', a geometry in which the boundaries of the two universes are glued together by a ``swaperator''. This description allows precise computation of a generalized entropy-like formula for entanglement entropy.The quantum extremal surface computing the entropy lives on the Lorentzian continuation of the cylinder/swap wormhole, which has a connected Cauchy slice stretching between the universes -- a realization of the ER=EPR idea. The new wormhole restores unitarity of quantum information. Based on 2104.13383
Jaydeep Kumar Basak	Indian Institute of Technology, Kanpur, India	Islands for Entanglement Negativity
We advance two alternative proposals for the island contributions to the entanglement negativity of various pure and mixed state configurations in quantum field theories coupled to semiclassical gravity. The first construction involves the extremization of an algebraic sum of the generalized Renyi entropies of order half. The second proposal involves the extremization of the sum of the effective entanglement negativity of quantum matter fields and the backreacted area of a cosmic brane spanning the entanglement wedge cross section which also extremizes the generalized Renyi reflected entropy of order half. These proposals are utilized to obtain the island contributions to the entanglement negativity of various pure and mixed state configurations involving the bath systems coupled to extremal and non-extremal black holes in JT gravity demonstrating an exact match with each other. Furthermore, the results from both the proposals match precisely with the island contribution to half the Renyi reflected entropy of order half providing a strong consistency check. We then allude to a possible doubly holographic picture of our island proposals and provide a derivation of the first proposal by determining the corresponding replica wormhole contributions. Based on 2012.03983

Plenary
Masamichi Miyaji	UC Berkeley	Entanglement of Initial State and Pseudo Entanglement Wedge
We consider spacetime initiated by a finite-sized boundary and study late time quantum entanglement. We find that the entanglement entropy of a large region is governed either by the initial state entropy or by the entanglement island when the naive initial state entropy appears to violate the area bound. Due to the absence of the moment of time reflection symmetry in the island and the projection introduced by the initial state, we find that the entanglement wedge reconstruction needs to be generalized. We propose {\it{pseudo entanglement wedge reconstruction}}, and show how this can be used to understand entanglement wedge reconstruction in gravity with an initial state. We also discuss the exponential hardness of such reconstruction task using Python's lunch conjecture.
Sotaro Sugishita	Nagoya University	Target space entanglement in quantum mechanics of fermions and matrices
We consider entanglement of first-quantized identical particles by adopting an algebraic approach. In particular, we investigate fermions whose wave functions are given by the Slater determinants, as for singlet sectors of one-matrix models. We show that the upper bounds of the general Renyi entropies are $N \log 2$ for $N$ particles or an $N\times N$ matrix. We compute the target space entanglement entropy and the mutual information in a free one-matrix model. We confirm the area law: the single-interval entropy for the ground state scales as $\frac{1}{3}\log N$ in the large $N$ model. We obtain an analytical $\mathcal{O}(N^0)$ expression of the mutual information for two intervals in the large $N$ expansion. Based on 2105.13726

Parallel Slot A
Sungjoon Kim	POSTECH	Non-unitary TQFTs from 3D N=4 rank 0 SCFTs
We propose a novel procedure of assigning a pair of non-unitary topological quantum field theories (TQFTs), TFT$_\pm [\mathcal{T}_{\rm rank \;0}]$, to a (2+1)D interacting $\mathcal{N}=4$ superconformal field theory (SCFT) $\mathcal{T}_{\rm rank \;0}$ of rank 0, i.e. having no Coulomb and Higgs branches. The topological theories arise from particular degenerate limits of the SCFT. Modular data of the non-unitary TQFTs are extracted from the supersymmetric partition functions in the degenerate limits. As a non-trivial dictionary, we propose that $F = \max_\alpha \left(- \log \|S^{(+)}_{0\alpha}\| \right) = \max_\alpha \left(- \log \|S^{(-)}_{0\alpha}\|\right)$, where $F$ is the round three-sphere free energy of $\mathcal{T}_{\rm rank \;0 }$ and $S^{(\pm)}_{0\alpha}$ is the first column in the modular S-matrix of TFT$_\pm$. From the dictionary, we derive the lower bound on $F$, $F \geq -\log \left(\sqrt{\frac{5-\sqrt{5}}{10}} \right) \simeq 0.642965$, which holds for any rank 0 SCFT. The bound is saturated by the minimal $\mathcal{N}=4$ SCFT proposed by Gang-Yamazaki, whose associated topological theories are both the Lee-Yang TQFT. We explicitly work out the (rank 0 SCFT)/(non-unitary TQFTs) correspondence for infinitely many examples. Based on 2103.09283
Ioannis Lavdas	LMU Munich	Boundaries and Topological Twists of 3d N=4 SCFTs
The significance of holomorphic boundaries of topologically twisted 3d $\mathcal{N}=4$ SCFTs relies on the understanding of the emergence of special vertex operator algebras in this framework and of their properties. In this talk I will discuss about certain aspects of such configurations using string theoretical and field theoretical approaches.
Parallel Slot B
Katsuta Sakai	KEK	Entanglement entropy in interacting field theories
Entanglement entropy (EE) in field theory has been discussed as a nice 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. Based on 2103.05303, 2105.02598, 2105.14834
Aranya Bhattacharya	Indian Institute of Science, Bangalore	Sub-region complexity of entanglement islands in AdS braneworld model
We study the entanglement islands and subsystem volume complexity corresponding to the left/ right entanglement of a conformal defect in d-dimensions in Randall-Sundrum (RS) braneworld model with subcritical tension brane. The left and right modes of the defect mimic the eternal black hole and radiation system respectively. Hence the entanglement entropy between the two follows an eternal black hole Page curve which is unitarity compatible. We compute the volumes corresponding to the left and right branes with preferred Ryu-Takanayagi (RT) surfaces at different times, which provide a probe of the subregion complexity of the black hole and the radiation states respectively. Based on 2103.15852

Parallel Slot A
Shuichi Yokoyama	Yukawa Institute for Theoretical Physics	Topologically protected phase factor, spin Chern-Simons theory and duality on lens space
Topologically protected phase factor has recently been recoginzed to produce important physics in theoretical physics.In this talk I will speak about its importance in 3d duality, or more concretely, in level-rank duality on 3d lens space.The level rank duality is strongly believed to hold for an arbitrary level and rank, though the explicit confirmation by using partition function was not achieved for spin case.In this situation we discover the correct partition function for non-abelian Chern-Simons theory on lens space in the sense to exhibit the expected well-known level rank duality for any rank and level including the total phase. This implies that the proposed partition function has the correct dependence on the background spin as well as the correct framing factor on lens space. Employing this we also provide strong evidence on level rank duality newly proposed by Hsin-Seiberg in arXiv:1607.07457. If time permits, I will comment on this perfect match of the lens space partition function including the total phase for a couple of Seiberg duality pairs including the matter contribution. This talk will be based on joint-work with Naotaka Kubo in YITP.
Zhenghao Zhong	Imperial College London	3d Mirrors of U & SU Quivers
In 3d N=4 gauge theories, mirror symmetry relates pairs of theories with identical vacuum structures. Such dualities give us the option to study the vacuum structure of the mirror dual if the original theory is too complicated. 3d mirror of linear quivers with only unitary gauge groups are well known. On the other hand, mirrors of quivers with special unitary groups remain elusive. Using recently developed tools of magnetic quivers, we are able to use brane webs to obtain the 3d mirror duals of all linear quivers containing a mixture of any number of unitary and special unitary gauge groups.
Parallel Slot B
Satoshi Kanno	University of Tsukuba	Various generalizations of the matrix regularization
We proposed various generalizations of the so-called matrix regularization, which plays important roles in the matrix-model formulations of superstring theory or M-theory. While the conventional matrix regularization is defined only for globally defined scalar fields,we generalized this in such a way that the regularization can also be applied to various other kinds of fields, such as tensor fields or scalar fields coupling tonontrivial gauge fields, which appear naturally in low energy physics of closed/open strings. Based on this generalization, we also proposed a general construction of the fuzzy Laplacian on any closed Riemann surface. This talk is based on a collaboration with H. Adachi, G. Ishiki and T. Matsumoto (hep-th/2103.09967). Based on 2103.09967
Mihailo Cubrovic	Institute of Physics Belgrade	Chaos and replica wormholes in the IIB matrix model
We study the dynamics and statistics of the Ishibashi-Kawai-Kitazawa-Tsuchiya (IKKT) IIB matrix model. We first consider the spectrum and detect signs of level repulsion and quantum chaos. Then we expand perturbatively the partition function of the quenched model and find that, with an appropriately chosen quenching, the expansion contains wormhole terms akin to those in the time-frozen SYK model. We conjecture that such terms are crucial in describing the chaotic aspects of the IIB model.

Invited
Sven Krippendorf	LMU München	Theoretical Particle Physics and Machine Learning
Many recent successes in machine learning (ML) resemble the success story in theoretical particle physics of utilising symmetries as organising principle. I discuss an introductory example where this procedure applied in ML leads to new insights in mathematical physics, more precisely for the study of Calabi-Yau metrics. Then I present methods on how to identify symmetries of a system without requiring knowledge about such symmetries, including also how to find a Lax pair/connection associated with integrable systems. If time permits, I discuss how latent representations in neural networks can offer a close resemblance of variables used in dual descriptions established analytically in physical systems.

Day 4
Invited
Teppei Kitahara	Nagoya	'Anomaly' in current low-energy data
Continuous development of experiments in recent years has revealed a large number of experimental anomalies that the Standard Model cannot explain. It is statistically obvious that as the number of experiments increases, so one encounters a new anomaly as the statistical fluctuation. But interestingly, some of these anomalies have been cross-checked by different experiments. Struggling to explain the anomalies by introducing new physics is a task of particle phenomenology, and the Standard Model also has such a history. In this talk, I will review the verified anomalies: the flavor anomalies, also known as lepton flavor universality violation, and the muon g-2 anomaly. I will also discuss these implications for the new physics.

Plenary
Hajime Otsuka	KEK	Hidden structures in the landscape of heterotic line bundle models
We show that neural networks can detect hidden structures in the string landscape, in particular, heterotic string theory on Calabi-Yau threefolds with line bundles. It turns out that three-generation models cluster in particular islands specified by deep autoencoder networks and k-means++ clustering.Especially, we explore mutual relations between model parameters and the cluster with densest three-generation models (called ``3-generation island"). We find that the 3-generation island has a strong correlation with the topological data of Calabi-Yau threefolds, namely, second Chern class of the tangent bundle of the Calabi-Yau threefolds. Based on 2003.11880
Naotaka Kubo	YITP	Non-perturbative Tests of Duality Cascades in Three Dimensional Supersymmetric Gauge Theories
We study the RG flow of three-dimensional N=3 supersymmetric Yang-Mills-Chern-Simons theories described by circular quiver diagrams. When the gauge group is U(N)×U(N+M) and M is larger than the Chern-Simons level, a duality cascade, which is a sequence of the Seiberg-like dualities, was expected to occur. It was also predicted that sometimes the supersymmetry would be dynamically broken. These properties can be fully captured by the braneology: the Hanany-Witten transitions and the s-rule. Based on this fact, we conjecture that the theories described by the general circular quiver diagrams also have similar properties. We test this prediction by using the partition function on S^3. The results are in agreement with our prediction. Based on 2010.15656

Plenary
Hitoshi Murayama	UC Berkeley, Kavli IPMU	Can we "solve" gauge theories?
I outline how dynamics of gauge theories can be studied using their supersymmetric versions perturbed by anomaly-mediated supersymmetry breaking (AMSB). For QCD-like theories, supersymmetric versions exhibit a wide array of phases, from run-away behavior, quantum modified moduli space, confinement without chiral symmetry breaking, free magnetic theories and IR fixed points. Once AMSB is introduced, they collapse to only two phases, one with chiral symmetry breaking and the other with IR fixed point. For $SO(N)$ gauge theory with $N-2$ flavors, I can demonstrate monopole condensation and chiral symmetry breaking simultaneously. I further extend the same methodology to chiral gauge theories, revealing very different phases from what had been conjectured in the past. I also present an argument why these results may connect continuously to the non-SUSY limits. Based on 2104.01179
Hiroaki Matsunaga	YITP, Kyoto Univ.	Path-integral as a homological perturbation
We give a physicist-friendly review of the following topics. The perturbative path-integral can be performed as a homological perturbation. Homotopy algebraic structure can be extracted from a given field theory, which is preserved under the perturbative path-integral. If there is time, we present several applications.

Parallel Slot A
Jinzhao Wang	ETH	The refined quantum extremal surface prescription from the asymptotic equipartition property
Information theoretic ideas have provided numerous insights in the progress of fundamental physics, especially in our pursuit of quantum gravity. In particular, the holographic entanglement entropy is a very useful tool in studying AdS/CFT, and its efficacy is manifested in the recent black hole page curve calculation. On the other hand, the one-shot information theoretic entropies, such as the smooth min/max-entropies, are less discussed in AdS/CFT. They are however more fundamental entropy measures from the quantum information perspective and should also play pivotal roles in holography. We combine the technical methods from both quantum information and quantum gravity to put this idea on firm grounds. In particular, we study the quantum extremal surface (QES) prescription that was recently revised to highlight the significance of one-shot entropies in characterizing the QES phase transition. Motivated by the asymptotic equipartition property (AEP), we derive the refined quantum extremal surface prescription for fixed-area states via a novel AEP replica trick, demonstrating the synergy between quantum information and quantum gravity. Based on 2105.05892
Yuji Igarashi	Faculty of Education, Niigata University	QED in the Exact Renormalization Group
The functional flow equation and the Quantum Master equation are consistently solved in perturbation for the chiral symmetric QED with and without four-fermi interactions. Due to the presence of momentum cutoff, unconventional features related to gauge symmetry are observed even in our perturbative results.In the absence of the four-fermi couplings, one-loop calculation gives us the Ward identity, Z1 = Z2, and the standard results of anomalous dimensions and the beta function for the gauge coupling. It is aconsequence of regularization scheme independence in one-loop computation. We also find a photon mass term.When included, four-fermi couplings contribute to the beta function and the Ward identity is also modified, Z1= Z2, due to a term proportional to the photon mass multiplied by the four-fermi couplings.
Parallel Slot B
Hiroyuki Kitamoto	Yukawa Institute for Theoretical Physics, Kyoto University	Semiclassical analysis of axion-assisted and axion-driven pair production
In JHEP 05 (2021) 001, it was reported that in the presence of a time dependent axion background field, the Schwinger pair production rate is enhanced by the axion velocity, and shows an oscillatory behavior. This phenomenon is called ``axion-assisted Schwinger effect''. In our study, we construct the semiclassical picture of pair production by interpolating the axion velocity dependence into the adiabatic mode functions. Our semiclassical analysis gives a simple description of the axion-assisted Schwinger effect, and also shows that there exists ``purely axion-driven pair production'' if the axion velocity changes with time.
Sravan K. Kumar	Tokyo Institute of Technology	String inspired non-local gravity, R^2-like inflation
The emergence of R^2 inflation which is the best fit framework for CMB observations to date comes from the attempts to attack the problem of quantization of gravity which in turn have resulted in the trace anomaly discovery. Further developments in trace anomaly and different frameworks aiming to construct quantum gravity indicate an inevitability of non-locality in fundamental physics at small time and length scales. A natural question would be to employ the R^2 inflation as a probe for signatures of non-locality in the early Universe physics. Recently R^2 inflation has been embedded in a string theory-inspired non-local gravity modification. We discuss the promising theoretical predictions of non-local R^2-like inflation with respect to the key observables such as tensor-to-scalar ratio, tensor tilt which tell us about the spectrum of primordial gravitational waves, and scalar Non-Gaussianities which tell us about the three-point correlations in the CMB fluctuations. Based on 1711.08864, 2003.00629

Parallel Slot A
Junggi Yoon	KIAS	TTbar deformation of N=(1,1) SUSY model and 3D N=2 Green-Schawrz action
In the talk, I will discuss the relation between $T\bar{T}$ deformation of $2d$ $\mathcal{N}=(1,1)$ SUSY model and $3D$ $\mathcal{N}=2$ Green-Schwarz action. First, I will present the Hamiltonian analysis of $T\bar{T}$ deformation of free $\mathcal{N}=(1,1)$ SUSY model, and I will show the non-SUSY $T\bar{T}$s deformation preserves $\mathcal{N}=(1,1)$ SUSY by calculating supercharge and its SUSY algebra. Then, I will describe how the $T\bar{T}$ deformed Hamiltonian can be obtained from $\mathcal{N}=2$ Green-Schwarz action for $3D$ target space. Finally, I will demonstrate the $3D$ $\mathcal{N}=2$ SUSY is equivalent to the $T\bar{T}$ deformed $\mathcal{N}=(1,1)$ SUSY together with global fermionic symmetry. Based on 2104.09529
Kushiro Shodai	Kyoto University	Chaotic string dynamics in deformed T^{1,1}
Recently, Arutyunov, Bassi and Lacroix have shown that 2D non-linear sigma model with a deformed $T^{1,1}$ background is classically integrable [arXiv:2010.05573 [hep-th]]. 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. We confirm this conjecure by explicitly presenting classical chaos. 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, which indicates non-integrability, by numerically computing Poincaré sections and Lyapunov spectra for some initial conditions. Based on 2103.12416
Parallel Slot B
Alberto Castellano Mora	IFT UAM-CSIC	The Gravitino Distance Conjecture
We conjecture that in a consistent supergravity theory with non-vanishing gravitino mass, the limit $m_{3/2}\rightarrow 0$ is at infinite distance. In particular one can write $m_\text{tower} \sim m_{3/2}^\delta$ so that as the gravitino mass goes to zero, a tower of KK states as well as emergent strings becomes tensionless. This conjecture may be motivated from the Weak Gravity Conjecture as applied to strings and membranes and implies in turn the AdS Distance Conjecture. Some evidence in type IIA vacua and F-theory settings will be presented. Moreover, we obtain general lower bounds $\delta\, \geq \, \frac{1}{3}, \, \frac{1}{4}$ for Calabi--Yau threefolds and fourfolds, respectively. The conjecture has important phenomenological implications, both for particle physics and cosmology. Based on 2104.10181

Invited
João Penedones	EPF Lausanne	Where is String Theory?
I will review the (numerical) S-matrix Bootstrap approach to scattering amplitudes. In particular, I will explain how this approach can be used to bound the space of Wilson coefficients in Effective Field Theories (EFT). I will focus on the application to supergravity in 10 spacetime dimensions. Remarkably, strongly coupled string theory seems to saturate the bounds imposed by Lorentz invariance, unitarity and causality Based on 2102.02847

Day 5
Invited
Alexander Maloney	McGill	Gravity from Averaging
I will explore the idea that certain theories of gravity in Anti-de Sitter space are dual to an average over an ensemble of quantum theories, rather than to a specific quantum theory. For example, the average over compact free boson CFTs in two dimensions takes the form of a sum over geometries in an exotic (but more-or-less exactly solvable) three dimensional theory of gravity. This theory includes a sum over wormholes which encodes the detailed spectral statistics of the ensemble of free boson CFTs. I will speculate on how this picture might need to be altered when one considers more complicated irrational CFTs.

Plenary
Yoshinori Matsuo	Kyoto University	Islands and vacuum states
Islands are located inside the horizon of evaporating black holes while they extend outside the horizon in the eternal black hole geometries. The difference comes from different vacuum states. In this talk, I will show that the location of the island in the Schwarzschild black hole depends on the vacuum states as an example. It also depends on the region of the Hawking radiation. The island in the Unruh vacuum is usually located inside the horizon but extends outside the horizon if the region of the Hawking radiation extends near the horizon. I will also comment on a possible relation to the stretched horizon. Based on 2011.08814
Kotaro Tamaoka	Nihon University	Product of Random States and Spatial (Half-)Wormholes
Recently, the connection between Euclidean wormholes and the ensemble average of theories has been widely discussed in the context of holography. In this talk, we will discuss the connection between the usual spatial wormhole and the ensemble average of states. This average over states can be interpreted as coarse graining. In particular, we will discuss a version of the factorization puzzle in this setup and its resolution, a Lorentzian analog of the half-wormhole. We will also comment on an operational interpretation of this wormhole. Based on joint work with Kanato Goto, Yuya Kusuki and Tomonori Ugajin.

Plenary
Sinya Aoki	Yukawa Institute for Theoretical Physics, Kyoto University	Conserved charges in general relativity and gauge theories
We discuss energy conservation in general relativity for 3 cases. (1) The corresponding Killing vector exists. (2) The energy is conserved even in the absence of the Killing vector. (3) The energy is not conserved but its generalization is conserved. As applications, we consider black holes and the compact star in the case (1), while the gravitational collapses and the gravitational waves in the case (2). We interpret the conserved charge in the case (3) as an entropy, by showing the 1st law of thermodynamics for a few cases including the expanding universe. We also discuss a similarity for conserved charges between general relativity and (classical) non-abelian gauge theories, by pointing out that the conserved energy we propose is different from those derived by the Noether's second theorem such as quasi-local energies. Based on 2005.13233, 2010.07660
Evgeny Sobko	PDMI&EIMI St.Petersburg	SU(N) Principal Chiral Model at Large N and the glimpse of a new String Theory
I will present a systematic, non-perturbative analysis of the two-dimensional SU(N) Principal Chiral Model (PCM) in the large-$N$ limit. Starting with the known infinite-N solution for the ground state at fixed chemical potential, we devise an iterative procedure to solve the Bethe ansatz equations order by order in $1/N$. The first few orders, which are explicitly computed, reveal a systematic enhancement pattern at strong coupling calling for the near-threshold resummation of the large-$N$ expansion. The resulting double-scaling limit bears striking similarities to the $c=1$ non-critical string theory and suggests that the double-scaled PCM is dual to a non-critical string with a $2+1$-dimensional target space where an additional dimension emerges from the $SU(N)$ Dynkin diagram. The talk is based on the joint work with V.Kazakov & K.Zarembo 1911.12860 and work in progress. Based on 1911.12860

Parallel Slot A
Daichi Takeda	Kyoto University	Interior Product, Lie Derivative and Wilson line in the KBc subsector of Open String Field Theory
It is known that there is a correspondence between Witten’s open string field theory and Chern-Simons theory in terms of their algebraic structure.In this talk, we introduce interior product and Lie derivative in open string field theory by restricting the theory to KBc sector.We find out a structure of manifold in KBc sector and construct Wilson line on the manifold by using these.In addition, we discuss the role of the Wilson line in open string field theory. Based on 2103.10597
Dorin Weissman	Okinawa Institute of Science and Technology	Cubic vertices for supersymmetric higher spin fields
We describe the BRST approach to construct interacting Lagrangians for higher spin fields, at the cubic level. Such an approach allows formulation of the equations for cubic vertices including bosonic and fermionic higher spin fields, and the problem of finding the vertices is reduced to finding the consistent solutions to these equations. As a concrete application of the generic scheme, we consider supersymmetric Yang-Mills-like systems in four, six and ten dimensions where the higher spin fields transform under some internal symmetry group, as well as supergravity-like systems in the same dimensions. Based on 2103.08231
Parallel Slot B
Yuki Sato	Nagoya U	Coleman's mechanism in 2d CDT
Causal dynamical triangulations (CDT) is a lattice model of quantum gravity. We show that in two-dimensional CDT the summation over all possible wormhole configurations leads to a kind of Coleman mechanism where the cosmological constant plays no role for large universes. Observers who are unable to observe the change in topology will naturally interpret the measurements of the size of the universe as being caused by a fluctuating cosmological constant, rather than fluctuating topology of spacetime. This talk will be based on a collaboration with Jan Ambjorn and Yoshiyuki Watabiki. Based on 2101.00478
Zixia Wei	Yukawa Institute for Theoretical Physics	Causal Structures and Nonlocality in Double Holography
Double holography plays a crucial role in recent studies of Hawking radiation and information paradox by relating an intermediate picture, in which a dynamical gravity living on an end-of-the-world brane is coupled to a non-gravitational heat bath, to a much better-understood BCFT picture and bulk picture. We discuss causal structures in generic double holographic setups in this talk. On the one hand, the causal structure in the bulk picture is compatible with causality in the BCFT picture, thanks to a generalization of the GaoWald theorem. On the other hand, the eﬀective theory in the intermediate picture should contain a special type of superluminal and nonlocal eﬀect to be compatible with the bulk picture. This is conﬁrmed by both geometrical analysis and commutators of microscopic ﬁelds. The subregion correspondences in double holography based on this nonlocality and possible fundamental origins of this nonlocality will also be discussed.

Parallel Slot A
Subramanya Hegde	Harish-Chandra Research Institute	N = 3 Conformal Supergravity in Four Dimensions
We derive the action for N = 3 conformal supergravity in four space-time dimensions. We construct a density formula for N = 3 conformal supergravity based on the superform action principle. Finally, we embed the N = 3 Weyl multiplet in the density formula to obtain the invariant action for N = 3 conformal supergravity. We will show that there are two inequivalent embeddings by changing a particular coefficient from real to imaginary. They lead to invariant actions, which will either be the supersymmetrization of the Weyl square term or the Pontryagin density in the eventuality of gauge fixing to Poincaré supergravity. We also discuss consistent truncation of N = 4 Weyl multiplet to N = 3 Weyl multiplet and use it for a robust check of our results using the earlier known results in N = 4 conformal supergravity. Based on 2104.07453
Tetsutaro Higaki	Keio University	4D effective action from 10D non-Abelian DBI action with magnetic flux background
We dimensionally reduce 10D non-Abelian Dirac-Born-Infeld action with magnetic flux on the extra dimension to obtain 4D N=1 supersymmetric effective action of gauge theories. We can obtain 4D chiral fermions via index theorem, and find a matter Kahler metric which depends on closed string moduli and the fluxes. The metric will be always positive if the system includes only positive (induced) RR charge of D-branes. We have derived such metric for the first time while the gauge couplings and the superpotential are already discussed in many literature. We will discuss also phenomenological applications.
Parallel Slot B
Sayantan Choudhury	NISER, Bhubaneswar	Wormhole calculus without averaging from $O(N)^{q-1} $ tensor model
The SYK model has a wormhole-like solution after averaging over the fermionic coupling in the nearly $AdS_2$ space. Even when the coupling is fixed the contribution of these wormholes continues to exist and new saddle points appear which are interpreted as "half-wormholes". In this paper, we will study the fate of these wormholes in a model without quenched disorder namely a tensor model with $O(N)^{q-1}$ gauge symmetry whose correlation function and thermodynamics in the large $n$ limit are the same as that of SYK model. We will restate the factorization problem linked with the wormhole threaded Wilson operator, in terms of global charges or non-trivial cobordism classes associated with disconnected wormholes. Therefore in order for the partition function to factorize especially at short distances, there must exist certain topological defects which break the global symmetry associated with wormholes and makes the theory devoid of global symmetries. We will interpret these wormholes with added topological defects as our "half-wormholes".
Mitsuhiro Nishida	Gwangju Institute of Science and Technology	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. Based on 2105.07778

Parallel Slot A
Akhila Mohan	BITS-PIlani Goa campus	Uniqueness of Galilean conformal electrodynamics and its dynamical structure
The Galilean field theories are developed to understand the low energy physics, where the velocity is very smallcompared to that of light. In this talk, We will look into the existence of action for the Galilean Electrodynamics using Helmholtz conditions. We further develop a consistent algorithm to construct the action. Using this algorithm we construct the unique action in magnetic limit of Galilean conformal electrodynamics. The check also implies the non existence of action in the electric sector of Galileanelectrodynamics. Further we will move on to the study of dynamical structure of the theory based on the action constructed. Based on 1909.11993
Parallel Slot B
Masahiro Nozaki	iTHEMS, Riken	Black-hole like excitation in conformal field theories.
We have studied the time evolution of entanglement entropy of the thermal state after an inhomogeneous quench. We have found that the all degrees of freedom gather together in a certain region, so that the entanglement entropy for the subsystem, including that region, is given by the thermal entropy, while the entanglement entropy for the subsystem, not including the region, exhibits volume-area phase transition. Thus, a local excitation excitation, having the thermal entropy, is created. In this talk, we will explain the detail of this non-equilibrium phenomena, and some of applications.
Ayan Kumar Patra	Saha Institute Of Nuclear Physics	Page Curves and Bath Deformations
We study the black hole information problem within a semiclassically gravitating AdS$_d$ black hole coupled to and in equilibrium with a $d$-dimensional thermal conformal bath. We deform the bath state by a relevant scalar deformation, triggering a holographic RG flow whose "trans-IR" region deforms from a Schwarzschild geometry to a Kasner universe. The setup manifests two independent scales which control both the extent of coarse-graining and the entanglement dynamics when counting Hawking degrees of freedom in the bath. In tuning either, we find nontrivial changes to the Page time and Page curve. We consequently view the Page curve as a probe of the holographic RG flow, with a higher Page time manifesting as a result of increased coarse-graining of the bath degrees of freedom.

YITP WorkshopStrings and Fields 2021

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YITP Workshop
Strings and Fields 2021