YITP Workshop
Strings and Fields 2016

August 8 (Mon) - 12 (Fri), 2016

Panasonic Hall and Rooms Y206 & Y306, Yukawa Memorial Building,
Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, Japan


August 8 (Mon)

Afternoon Session 1 (13:00-14:10)
Masahiro Ibe* Institute for Cosmic Ray Research Status of Beyond the Standard-Model at the LHC*
The LHC is now taking a lot of physics data at center-of-mass energy of 13TeV, which will provide new insights for physics beyond the Standard Model. In this talk, I review the current status of searches for new physics beyond the Standard Model at the end of Run I (7TeV and 8TeV) and the early stage of Run II (13TeV) by the ATLAS and CMS experiments. I also discuss some implications of the tentative hint on the 750GeV diphoton resonance if the excess remains.
Afternoon Session 2 (14:40-15:55)
Toshifumi Noumi Hong Kong University of Science and Technology Unitarity constraints on single-field inflation
We provide a class of consistency conditions constraining the EFT of single-field inflation based on the unitarity of inflationary perturbations. By analogy with the partial wave unitarity of scattering amplitudes, we introduce a two-parameter family of positivity conditions on inflationary four-point functions in the collapsed limit. In particular our unitarity constraints require the subluminality of inflationary perturbations in addition to a certain positivity conditions on EFT parameters, one of which was derived by Baumann et al. from analyticity of non-relativistic scatterings. We demonstrate that angular dependence of inflationary correlation functions plays a crucial role to reproduce the subluminality conditions. Observational prospects of our unitarity constrains are also discussed.
Kouhei Hasegawa Kobe University Toward a solution to fermion generation problem from 6D space-time with a suitable boundary condition
Relying on action principle, we classify the class of boundary conditions (B.C.) at 6D fermion theory, and obtain the mass spectra on each class. When we choose a suitable B.C., it is shown that there appears two chiral zero modes, which can be identified as the first and second generation of the chiral fermions at standard model. In such a way, the mechanism demonstrated at this 6D model can provide the origin of the fermion generation structure. In addition, it is also shown that the mode functions of the two chiral zero modes are localized at most far places each other on the extra dimension plane. Then we show that such a localization profile can induce the fermion mass hierarchy at 4D effective theory in a natural way.
Hajime Otsuka Waseda University Axion decay constants at special points in type II superstring theory
We propose the mechanism to disentangle the decay constant of closed string axion from the string scale in the framework of type II string theory on Calabi-Yau manifold with single and multiple axions. The quantum corrections in the prepotential that arise at some special points in the moduli space widen the window of axion decay constant. We also discuss the moduli stabilization leading to the phenomenologically attractive low-scale and high-scale axion decay constants.
Afternoon Session 3 (16:10-17:50)
Tomoki Nosaka Korea Institute for Advanced Study Orientifold ABJM Matrix Model: Chiral Projections and Worldsheet Instantons
We study the partition function of the N=5 superconformal Chern-Simons theory with O(2M)xUSp(2N) gauge group (OSp model) on three sphere. This theory is realized from the type IIB brane system for the ABJM theory by adding an O3 plane parallel to the D3-branes. Recently, from the exact computation for small k, M and N an interesting relation was observed between the partition functions of these two theories: in the Fermi gas formalism for the partition function, the orientifold planes act as chirality projections on the one dimensional quantum statistical system of Fermi gas. We give a direct proof of the relation for arbitrary Chern-Simons level k and the ranks of the gauge groups (M,N). We also discover a formula to generate the worldsheet instanton effects in OSp models directly from those in the ABJM theory. The talk is based on the collaborative work arXiv:1603.00615 with Sanefumi Moriyama in Osaka City University.
Sanefumi Moriyama Osaka City University Giambelli Identity in Super Chern-Simons Matrix Model
A classical identity due to Giambelli in representation theory states that the character in any representation is expressed as a determinant whose components are characters in the hook representation constructed from all the combinations of the arm and leg lengths of the original representation. Previously it was shown that the identity persists in taking, for each character, the matrix integration in the super Chern-Simons matrix model in the grand canonical ensemble. We prove here that this Giambelli compatibility still holds in the deformation of the fractional-brane background.
Takao Suyama Osaka City University Notes on Planar Resolvents of Chern-Simons-matter Matrix Models
We revisit planar resolvents of matrix models corresponding to ${\cal N}\ge3$ Chern-Simons-matter theories with the gauge groups of the form ${\rm U}(N_1)\times{\rm U}(N_2)$ coupled to any number of bi-fundamental hypermultiplets. We find that the derivative of a suitably defined planar resolvent can be written explicitly. From this resolvent, we derive the explicit formula for (a linear combination of) the vevs of BPS Wilson loops.
Toshiaki Fujimori Keio University Complex saddle points and non-perturbative effects in $CP^N$ model
When we apply the saddle point method to path integrals, it is important to take into account complex saddle points obtained by complexifying the path integral. We discuss complex saddle points corresponding to instanton-antiinstanton (bion) configurations in the $CP^N$ quantum mechanics. Such complex s solutions play an important role when we show the cancelation of non-perturbative corrections to the supersymmetric ground state energy. To compute non-perturbative corrections to the (non-)supersymmetric ground state energy, we consider the integral along the Lefschetz thimbles attached to the saddle points corresponding to the saddle points. This method can be viewed as a rigorous version of the Bogonolnyi- Zinn-Justin calculation of the instanton-antiinstanton contributions. In the end, we obtain the non-perturbative contributions from the real and complex solutions in the $CP^N$ quantum mechanics, which should be of importance in the resurgent trans-series.

August 9 (Tue)

Morning Session 1 (9:00-10:10)
Ashoke Sen* Harish-Chandra Research Institute Applications of superstring field theory*
Superstring perturbation theory is free from ultraviolet divergences but suffers from the usual infrared problems of quantum field theory that arise when we do not take into account the effect of quantum corrections to the vacuum or to the asymptotic states. Examples of such divergences include tadpole and mass renormalization effects. In superstring perturbation theory these divergences arise from the boundary of the moduli space of Riemann surface where the surface degenerates. However unlike in quantum field theories, the usual superstring perturbation theory does not have a mechanism to cure these divergences. In this talk I shall describe how superstring field theory can be used to address these issues.
Morning Session 2 (10:40-11:30)
Toru Masuda Nara Women's University Topological defects in open string field theory
We show how conformal field theory topological defects can relate solutions of open string field theory for different boundary conditions. To this end we generalize the results of Graham and Watts to include the action of defects on bcc operators. We find the fusion algebra of defects is realized on open string fields only up to a star algebra isomorphism. In the previous report (based on the work with T. Kojita, C. Maccaferri and M. Schnabl, to appear), we took a bootstrap approach to identify the action of topological defects on bcc operators for the diagonal minimal models. This time, we also present direct calculation for simple theories such as the free boson CFT.
Kenji Hotta Hokkaido University Unruh Effect in Closed String Theory
Previously, Unruh effect in open bosonic string field theory was discussed by Hata, Oda and Yahikozawa. However, it is natural to argue this effect for the closed strings which can propagate bulk spacetime. We investigate Unruh effect in the case of closed strings on the basis of light-cone gauge string field theory proposed by Kaku and Kikkawa. By superposing the solutions of the Klein-Gordon equation in Minkowski spacetime, we construct the string fields which satisfy the Klein-Gordon equation in Rindler spacetime. Using these string fields, we show that the Minkowski vacuum is a thermal state for closed strings in the Rindler wedge.
Morning Session 3 (11:45-13:00)
Yuho Sakatani Kyoto Prefectural University of Medicine Branes in extended spacetime
We propose worldvolume theories for various branes in string/M-theory based on the geometry of the double field theory or the exceptional field theory. We show that our action can correctly reproduce the conventional string/membrane action. Worldvolume theories for an M5-brane and an exotic brane are also discussed. This talk is based on arXiv:1607.04265 in collaboration with Shozo Uehara.
Masaya Yata National University of Singapore Exotic Five-branes in Heterotic Supergravity
In string theory, there are many kinds of extended objects ''brane'' and the brane, which has non-trivial monodromy, is known as the exotic-brane. For example, type IIB seven branes are the most famous exotic-brane. In particular, the five dimensional objects are called as exotic-five brane and the well-known one is ''522-brane'' which is a type II supergravity solution. In this work, we construct the exotic five-brane in Heterotic supergravity. The exotic brane is obtained by Heterotic T-duality, which includes non-zero gauge fields and alpha'-corrections, with Heterotic NS5-brane solution and we show that the exotic brane agrees with the solution found by the standard embedding of the type II 522-brane. The monodromy structure of the Heterotic exotic brane is confirmed by the extended generalized metric including non-zero gauge fields. We also show that the structure is same as the monodromy of type II 522 due to the standard embedding.
Tetsuji Kimura Keio University Exotic Brane Junctions from F-theory
Applying string dualities to F-theory, we obtain various [p,q]-branes whose constituents are standard branes of codimension two and exotic branes. We construct junctions of the exotic five-branes and their Hanany-Witten transitions associated with those in F-theory. In this procedure, we understand the monodromy of the single $5^2_2$-brane. We also find the objects which are sensitive to the branch cut of the $5^2_2$-brane. Considering the web of branes in the presence of multiple exotic five-branes analogous to the web of five-branes with multiple seven-branes, we obtain novel brane constructions for $SU(2)$ gauge theories with $n$ flavors and their superconformal limit with enhanced $E_{n+1}$ symmetry in five, four, and three dimensions. Hence, adapting the techniques of the seven-branes to the exotic branes, we will be able to construct F-theories in diverse dimensions.
Afternoon Session 1 (14:30-15:20)
Marc Andre Heller Tohoku University Higher gauge theories and their off-shell covariatization
We construct higher gauge theories containing 2- and 3-form curvatures in various dimensions making use of the supergeometric QP-manifold method, which induces a BRST-BV formalism. Structurally equivalent higher gauge theories are identified on the gauge algebra level. A method of off- shell covariantization is proposed that achieves to covariantize the gauge transformation of the 3-form curvature while circumventing the so-called fake curvature condition by constraining the auxiliary gauge fields. We explicitly derive such a gauge algebra in 5 dimensions as a nontrivial extension of a differential crossed module within a symplectic Lie 4-algebra and show its off-shell closure.
Yoshinori Honma National Tsing-Hua University Open Mirror Symmetry for Higher Dimensional Calabi-Yau Hypersurfaces
Compactifications with fluxes and branes motivate us to study various enumerative invariants of Calabi-Yau manifolds. In this talk, we will discuss about non- perturbative corrections depending on both open and closed string moduli for a class of compact Calabi-Yau manifolds in general dimensions. Our analysis is based on the methods using relative cohomology and generalized hypergeometric system. For the simplest example of compact Calabi-Yau fivefold, we explicitly derive the associated Picard-Fuchs differential equations and compute the quantum corrections in terms of the open and closed flat coordinates. Implications for a kind of open-closed duality are also discussed.
Afternoon Session 2 (15:30-18:00)

Poster Session 1

List of Posters
Yuki Amari Tokyo University of Science Quantum mechanical aspects of $CP^2$ baby Skyrme model
The $CP^N$ extended Skyrme-Faddeev model possesses planar soliton solutions. We consider quantum aspects of the solutions applying collective coordinate quantization in regime of rigid body approximation. In order to discuss statistical properties of the solutions we include the Hopf term in the Lagrangian. Since $\Pi_3(CP^1) = \mathbb{Z}$ then for $N = 1$ the term becomes integer. On the other hand for $N > 1$ it becomes perturbative because $\Pi_3(CP^N)=0$. The prefactor of the Hopf term (anyon angle) $\Theta$ is not quantized and its value depends on the physical system. If $\Theta = n\pi$, $n\in \mathbb{Z}$,the soliton with $N = 1$ is not an anyon type. For $N > 1$, however, its statistics is always anyonic.(arXiv:1604.06125)
Hiroto Hosoda Nagoya University On three-dimensional trace anomaly from holographic local RG
Odd-dimensional quantum field theories (QFTs) can have nonzero trace anomalies if external fields are introduced and some ingredients needed to make Lorentz scalars with appropriate mass dimensions (or weights) are supplied. We have studied a three-dimensional QFT and explicitly computed the trace of the stress tensor using the holographic local renormalization group (RG). We have checked some properties of vector beta functions and the Wess-Zumino consistency condition, however, found the anomalies vanish on fixed points. We clarify what is responsible for the vanishing trace anomalies.
Shoichi Ichinose University of Shizuoka Geometrical Approach to Dissipative Systems and Discrete Morse Flow Method
A geometrical approach to the friction phenomena is presented. It is based on the holographic view (AdS/CFT). The heat-producing phenomena are most widely treated by using the non-equilibrium statistical physics. As the system development, we take the discrete Morse flow method. The step number is used instead of time. Various advantages of this method is examined. 1. It is formulated by the minimal energy principle. 2. The energy function (at the n-th step) is taken as the (energy)line-eliment. This defines the geometry of the system. 3. The difficulty of the hysteresis quantity (non-Markovian effect) evaluation is avoided. References: Tribology International (Elsevier)93PA,446(2016) arXiv:1404.6627; arXiv:1303.6616
Yukio Kaneko Tohoku University Higher gauge theories based on QP-manifold
We study higher gauge theories using a QP-manifold which is a differential graded symplectic manifold. A QP-manifold characterizes a gauge symmetry of a higher gauge theory, in addition, gauge transformations and field strengths can be derived systematically. We analyze canonical transformations on QP-manifolds and investigate the structure of gauge theories based on canonical transformed system. We also find that in five-dimensional spacetime there is nontrivial extensions of the standard higher gauge algebra. In this case, a restriction of the gauge symmetry by imposing constraints on the auxiliary fields leads to a covariantized theory.
Hirotaka Kato Tokyo Institute of Technorogy Supersymmetry Enhancement and Junctions in S-folds
Recently N=3 supersymmetric theories have been constructed as $Z_k$ orbifolds (S-folds). Aharony and Tachikawa proposed that the N=3 supersymmetry is enhanced to N=4 in some brane configurations in S-folds. We studied string junctions in the brane configurations, and checked the consistency to those of N=4 supersymmetric Yang-Mills theories.
Shoichi Kawamoto Chung-Yuan Christian University Entropic uncertainty relation based on generalized uncertainty principle
We explore the modification of the entropic formulation of uncertainty principle in quantum mechanics which measures the incompatibility of measurements in terms of Shannon entropy. The deformation in question is the type so called generalized uncertainty principle that is motivated by thought experiments in quantum gravity and string theory and is characterized by a parameter of Planck scale. The corrections are evaluated for small deformation parameters by use of the Gaussian wave function and numerical calculation. As the generalized uncertainty principle has proven to be useful in the study of the quantum nature of black holes, this study would be a step toward introducing an information theory viewpoint to black hole physics.
Takaki Matsumoto University of Tsukuba Kahler structure of perturbed fuzzy sphere
In matrix models, the matrix geometry appears naturally in describing the fundamental objects in the string/M-theories and plays an important role in formulating these theories. We consider the commutative limit of the matrix geometry described by a large-N sequence of some Hermitian matrices. We find that the geometry which appears in the commutative limit possesses a Kahler structure under some assumptions. In addition, we propose an expression of the Kahler structure in terms of given matrices. As a concrete example of this result, we consider the fuzzy sphere and the perturbation around it. We analyze the Kahler structure on the commutative geometry of the perturbed fuzzy sphere. We also discuss how the nonlocality of the fuzzy sphere affects the result of our analysis. (arXiv:1603.09146)
Satsuki Matsuno Osaka City University Giambelli identity in super Chiern-Simons matrix model
A classical identity due to Giambelli in representation theory states that the character in any representation is expressed as a determinant whose components are characters in the hook representation constructed from all the combinations of the arm and leg lengths of the original representation. Previously it was shown that the identity persists in taking, for each character, the matrix integration in the super Chern-Simons matrix model in the grand canonical ensemble. We prove here that this Giambelli compatibility still holds in the deformation of the fractional- brane background.
Akane Oikawa Waseda University New potentials for string axion inflation
We propose a new type of axion inflation with complex structure moduli in the framework of type IIB superstring theory compactified on the Calabi-Yau manifold. The inflaton is identified as the axion for the complex structure moduli whose potential is originating from instantonic corrections appearing through the period vector of the mirror Calabi-Yau manifold. The axionic shift symmetry is broken down to the discrete one by the inclusion of the instantonic correction and certain three-form fluxes. Our proposed inflation scenario is compatible with Kahler moduli stabilization. We also study a typical reheating temperature in the case of complex structure moduli inflation.
Hongfei Shu Tokyo Institute of Technology ODE/IM correspondence for modified $B_2^{(1)}$ affine Toda field equation
We study the massive ODE/IM correspondence for modified $B_2^{(1)}$ affine Toda field equation.Based on the $\psi$-system for the solutions of the associated linear problem, we obtain the Bethe ansatz equations. We also discuss the T-Q relations, the T-system and the Y-system, which are shown to be related to those of the $A_3/{\bf Z}_2$ integrable system. We consider the case that the solution of the linear problem has a monodromy around the origin, which imposes nontrivial boundary conditions for the T-/Y- system. The high-temperature limit of the T- and Y-system and their monodromy dependence are studied numerically.
Yuji Sugimoto Osaka University The non-perturbative effect of Geometric transition in Topological string theory
We consider the geometric transition in the topological string theory including non-perturbative effects. We calculate the free energy including non-perturbative effects in topological string theory on toric Calabi-Yau manifold known as Local $\mathcal{B}_3$. Then we show that when we consider the geometric transition which changes the background geometry, we observe the non-perturbative effects in the special values of the Kahler parameters.
Kazuhiro Sugita Nihon University Multiple Exotic Solutions in Superstring Field Theory
In bosonic open string field theory, "multiple"-brane solutions which have energy of $n$ D-branes are constructed by performing singular gauge transformations $n$ times. In cubic superstring field theory, an exotic solution is known. The energy of the solution is half the tension of a D-brane. In this talk we study "multiple"-exotic-brane solutions using the technique of the bosonic theory.
Tomoyuki Takezaki University of Tokyo Complete Action for Open Superstring Field Theory with Cyclic $A_\infty$ Structure
String field theory is an approach to nonperturbative formulations of string theory. When we quantize open string field theory, the structure called $A_\infty$ plays a crucial role. We construct a gauge invariant action for the Neveu-Schwarz and Ramond sectors of open superstring field theory realizing a cyclic $A_\infty$ structure, providing the first complete and fully explicit solution to the classical Batalin-Vilkovisky master equation in superstring field theory. We also demonstrate the equivalence of our action to the Wess-Zumino-Witten-based construction of Kunitomo and Okawa. This is based on arXiv:1602.02582 with Erler and Okawa.
Kentaro Tatsumi Kobe University Hidden quantum mechanical supersymmetry in 6D fermion system with boundary
We reveal that quantum mechanical supersymmetry is hidden in a system of six dimensional fermions with two extra dimensions. Based on it, we succeed in classifying 4d Lorentz invariant boundary conditions completely and obtaining 4d mass spectrum of the model. It is shown that, despite the existence of 6d bulk mass, there appear two 4d massless chiral modes because of boundary conditions.
Xi Wu Osaka University Generic boundary conditions in topological phases
We study most generic boundary conditions for 1+2-dimensional relativistic fermion system. Topological insulators of class A is one of such systems, and we find the dispersion relations of the edge-localized states. We found the edge states depend only on a single real parameter appearing in the boundary condition, and the dispersion changes from a linear to a flat band as we change the parameter. The edge state dispersion always touch the bulk dispersion.

August 10 (Wed)

Morning Session 1 (9:00-10:10)
Yu-tin Huang* National Taiwan University Lessons from perturbative unitarity in graviton scattering amplitudes*
In this talk I will discuss the constraint on perturbative completion of massless spinning particles. For theories involving three-point interactions, such as Yang-Mills and Gravity, I will show that under simple assumptions we immediately arrive on a completion that is universal in all perturbative string theories. We will present a measure of such uniqueness by showing that a general class of possible deformations cannot be unitary without such universal piece. This study will present an interesting "twist" for which one can remove all massive states from the string spectrum while retaining the worldsheet interpretation. This turns out directly leads to the Hohm-Siegel-Zwiebach theory and the recent "scattering equations" by Cachazo, He and Yuan.
Morning Session 2 (10:40-11:30)
Masafumi Ishihara Advanced Institute for Material Research, Tohoku University Holographic Schwinger Effect and Chiral condensate in SYM Theory
By using the holographic duality, we study the Schwinger pair production rate from the imaginary part of the on-shell D7-brane action embedded in the 10-dimensional gravity background which is dual to the confinement field theory with broken chiral symmetry. By comparing the production rate in this background with the one obtained in $AdS_5\times S^5$, we calculate the relation between the dynamical quark mass and VEV of chiral condensate, and compare the result with the dynamical quark mass given by the Nambu-Jona-Lasinio model.
Koji Hashimoto Osaka University Chaos of chiral condensate
Assigning a chaos index for vacua of generic quantum field theories is a challenging problem. We find chaotic behavior of chiral condensates of a quantum gauge theory at strong coupling limit, by using the AdS/CFT correspondence. At an equivalent classical gravity picture, a Lyapunov exponent is readily defined. We first study a linear sigma model of low energy QCD as a toy example and find a chaos at 140 MeV energy scale. Then we study $SU(N_c)$ $N = 2$ supersymmetric QCD at large Nc and at large t Hooft coupling lambda, and evaluate the time evolution of homogeneous chiral condensates, which exhibit chaotic behavior for energy density $E > (6\cdot 10^2) (m_q)^4(N_c/\lambda^2)$ where $m_q$ is the quark mass. The vacuum of the $N = 2$ supersymmetric QCD is more chaotic for larger  lambda or for smaller $N_c$. The work is in collaboration with Keiju Murata and Kentaroh Yoshida.
Morning Session 3 (11:45-13:00)
Masamichi Miyaji Yukawa Institute for Theoretical Physics Butterflies from Quantum Fidelity
We point out that, rapid growth of information metric of Thermofield double state corresponds to growth of commutators of local operators, which implies scrambling. Following holographic proposal for information metric, we compute information metric of thermofield double states for marginal deformation, by evaluating volume of maximal volume codimension 1 surface. We confirm that information metric increases exponentially with time. Our result implies orbits of thermofield double states in chaotic system are sensitive to change of outer environment.
Kento Watanabe Yukawa Institute for Theoretical Physics EPR Pairs, Local Projections and Quantum Teleportation in Holography
Operation is an important concept in quantum systems. In this talk, we discuss 3 quantum operations in QFTs, especially in 2d CFTs : local projection measurements, creations of partial entanglement between two CFTs and swapping of subsystems between two CFTs. We also discuss their holographic duals and the time evolutions of the entanglement entropy. By combining these operations, we present an analogue of quantum teleportation between two CFTs and give its holographic realization. Furthermore, we introduce a new quantity to probe multi- partite entanglement by using local projection measurements. This talk is based on a work with Tokiro Numasawa, Noburo Shiba and Tadashi Takayanagi.
Kanato Goto University of Tokyo Causal Evolutions of Bulk Local Excitations from CFT
Bulk localized excited states in an AdS spacetime can be constructed from Ishibashi states with respect to the global conformal symmetry in the dual CFT. We study boundary two point functions of primary operators in the presence of bulk localized excitations in two dimensional CFTs. From two point functions in holographic CFTs, we observe causal propagations of radiations when the mass of dual bulk scalar field is close to the BF bound. This behavior for holographic CFTs is consistent with the locality and causality in classical gravity duals. We also show that this cannot be seen in free fermion CFTs. Moreover, we find that the short distance behavior of two point functions is universal and obeys the relation which generalizes the first law of entanglement entropy.
Afternoon Session 1 (14:30-14:55)
Tsukasa Tada RIKEN Dipolar Quantization of conformal field theories
Conformal symmetry is isomorphic to SO(D+1,1), the symmetry of the Lorentz transformation. Thus, all the possible spacetime foliations are subject to this transformation. Among these foliations, those which correspond to a light cone under the transformation stand out. Dipolar quantization adopts these idiosyncratic spacetime foliations. In contrast to radial quantization, dipolar quantization yields continuous spectra for conformal field theories as expected on the ground of the association with a light cone and the consequential masslessness. We discuss the implications of dipolar quantization to, in particular, two-dimensional conformal field theories.
Afternoon Session 2 (15:05-17:35)

Poster Session 2

List of Posters
Filip Blaschke Yamagata University BPS Boojums in N=2 supersymmetric gauge theories
We study 1/4 Bogomol'nyi-Prasad-Sommerfield (BPS) composite solitons of vortex strings, domain walls and boojums in ${\cal N}=2$ supersymmetric Abelian gauge theories in four dimensions. We obtain both numerical and analytical solutions to the 1/4 BPS equations with the finite gauge coupling constant. We examine various configurations and clarify how the shape of the boojum depends on the coupling constants and moduli parameters. We introduce a `magnetic' scalar potential which offers an intuitive understanding that the end point of vortex string is a source of magnetic field, but also it gives a physical meaning to the scalar function appearing in the Taubes' equation for BPS Abrikosov-Nilsen-Olesen vortex. Dyonic solutions are also obtained. When the configuration is extended to the dyonic case, the domain wall becomes an electric capacitor storing electric charge on its skin and the boojum charge density becomes proportional to $\vec E \cdot \vec B$. We also find analytic solutions to the 1/4 BPS equations for specific values of the coupling constants.
Hiroshi Isono Chulalongkorn University Holographic Non-Gaussianity in Single-field Inflations
Holographic approach to inflationary cosmology is discussed. We compute the power spectrum and bispectrum of single-field slow-roll inflation and K-inflation using three-dimensional conformal field theory (CFT) with nearly marginal deformations, and compare them with results on the inflation side. In particular, we find appropriate sets of parameters to characterise the undeformed CFT and renormalisation group flows induced by the deformations, and show that they can reproduce nontrivial features of the inflation models of our interest, such as red spectrum, nontrivial sound speed, non-Gaussianity.
Yuto Ito Korea Institute for Advanced Study Superconformal index with surface defects for class $\mathcal{S}_k$
We study surface defects in 4d $\mathcal{N}=1$ $SU(N)$ superconformal gauge theories of class $\mathcal{S}_k$ obtained from the 6d (1,0) theories of type $A_{N-1}$, which are worldvolume theories on $N$ M5-branes at $C^2/Z_k$ singularities, compactified on Riemann surfaces with punctures. First we apply a method based on Riemann surface description and obtain the superconformal index of the theories in the presence of surface defects labelled by symmetric representations of $su(N)$. Then we propose another description for the same surface defects, which involves 4d-2d coupled systems and reproduce the results obtained from the first method. Finally we study the 2d TQFT structure of the index for class $\mathcal{S}_{k}$ theories by obtaining several eigenfunctions and eigenvalues of the difference operators that capture the surface defects and checking their relation.
Naoki Kiryu University of Tokyo Integrable Bootstrap for Open String Correlators
We study the three-point functions of the operators inserted on top of the 1/2 BPS Wilson loop in N= 4 super Yang-Mills. We propose that they can be decomposed into two kinds of fundamental objects: The one is the hexagon, which appears also in the study of the three-point functions of the single-trace operators. The other is a new object, the square with a boundary corresponding to the Wilson loop. We shall conjecture that the three-point functions can be obtained by gluing together one hexagon and three squares. To test the conjecture, we compute the tree-level three-point functions. In addition, we compute the three-point function of the “boundary changing operators” which change the scalar coupled to the Wilson loop. We conjecture that the contribution is corresponding to the non-trivial effect so called the wrapping correction in the context of integrability-based approach. Then we focus on the special scaling limit called the ladders limit. In this limit, we determine the structure constants at all-order in the rescaled coupling using the Schwinger-Dyson equation. The work is in collaboration with Minkyoo Kim, Shota Komatsu and Takuya Nishimura.
Hiroaki Matsunaga ASCR Alternative WZW-like actions for string field theories
By recursively adding infinitely many regulators to Witten’s cubic (but singular) theory, one can obtain gauge invariant actions for NS and NS-NS superstring field theories, which are so-called $A_{\infty}/L_{\infty}$ actions. We show there exist natural duals of these $A_{\infty }/L_{\infty }$ gauge structures: In this dual description, the role of constraint equations and on-shell conditions is switched. Utilizing these dual $A_{\infty }/L_{\infty}$, we give ''alternative'' WZW-like actions, which are rather suitable and useful to include the Ramond sector than known WZW-like actions. We also show the equivalence between alternative WZW-like actions and known $A_{\infty }/L_{\infty }$ actions, and discuss the relation to known WZW-like actions.
Hironori Mori Osaka University Surface Operators and M-strings
We study surface operators in 4d supersymmetric gauge theories. In the context of AGT correspondence it was shown that the surface operators are mapped to degenerate operators of 2d CFTs on a Riemann surface. AGT relation can be encoded into string theory through the correspondence between brane webs and toric Calabi-Yau’s, which allows us to be able to compute a partition function of the 4d gauge theory by the refined topological vertex. Further, the surface operator in this duality can emerge from the geometric engineering of the brane web, and its contribution in the partition function can be calculated again by the topological string. Recently, an application of the topological string to M-theory was proposed as M-strings. We find a M-theoretic configuration compatible with M-strings which geometrically engineers the surface operators in 4d $\mathcal{N}=2$ gauge theories.
Kazuhisa Nishi Toyohashi University of Technology A new root to quantum gravity enlightened by the reformulation of AdS/CFT correspondence in Hausdorff space
In spite of much study about the quantization of gravity, it remains an unsolved problem. Many approaches including superstring theory have concentrated on the unification of general relativity and quantum field theory. However, if there exists a final theory of quantum gravity, it would be related with the various roots to the conventional and standard physical theories. Here a new type of the quantum gravity theory is investigated by reformulating special relativity into Hausdorff space which is one of the general topological spaces. It is found that the reformulation of AdS/CFT correspondence in Hausdorff space could enlighten a new root from special relativity to the quantum gravity theory.
Yuichi Ohara Nagoya University Self-interacting massive spin two particles
We constructed a model of self-interacting charged massive spin two particles by using the interaction proposed by Hinterbichler. Then, we investigate the some basic properties of this theory and compare the result with the model of neutral massive spin two particles.
Kazuma Shimizu Yukawa Institute for Theoretical Physics Mass Deformed ABJM Theory in Large N
We study mass deformed ABJM theory in the large N limit. This theory has the aspect as M2-M5 brane systems. The exact partition function on S^3 is described by the matrix model by using localization method. The matrix model can be evaluated with saddle point approximation in the large N limit. We have improved the previous our results (arXiv:1512.00249). We find new solutions of saddle point equation in the mass parameter region where we could not solve the saddle point equation. We discuss various phases of this theory depending on the mass parameter. This presentation is based on the collaboration with Tomoki Nosaka, Seiji Terashima.(arXiv:1606.xxxxx)
Kiyoshi Shiraishi Yamaguchi University GR-GSG Hybrid Gravity
We propose a model of gravity in which the mixing of a metric tensor of General Relativity and an effective metric generated from a single scalar as formulated in Geometric Scalar Gravity. We show that the model admits the exact Schwarzschild solution and an accelerating behavior of scale factors in cosmological solutions.
Hiroki Sukeno University of Tokyo Fermion scattering amplitudes from gauge invariant actions for open superstring field theory
Recently, complete actions for open superstring field theory were constructed. In the perturbation theory of 1st quantized strings, covering of the moduli space of Riemann surface is crucial for ensuring the decoupling of unphysical degree of freedom. On the other hand, in string field theory, the scattering amplitude is obtained from summation over various Feynman diagrams. In this poster, we explicitly calculate tree-level scattering amplitudes from Wess- Zumino-Witten like formulation of complete open superstring field theory, and show that they reproduce correct tree-level amplitudes of 1st quantized open superstring theory. We discuss the roll of higher order vertices in Wess- Zumino-Witten like action for covering the supermoduli space of super- Riemann surfaces.
Koki Takesue Kitasato University Holographic Skyrme model in seven dimensions.
It is well known that the Atiyah-Manton construction can be produced Skyrmions (which are solutions of the Skyrme model in three dimensions) from four-dimensional instantons. In higher dimensions, we can consider a higher dimensional ''instanton'' by generalize the self-duality relation in four dimensions. Can we use the Atiyah-Manton construction in higher dimensions to produce the higher dimensional ''Skyrmions'' ? In this poster, we introduce a seven-dimensional Skyrme model from a holography of the eight-dimensional (Quartic) Yang-Mills model, and we consider a seven-dimensional Skyrmion which are produced from the eight-dimensional instanton by using the Atiyah-Manton construction in seven dimensions.
Wen-Yu Wen Chung Yuan Christian University Extremal noncommutative black holes as dark matter furnaces
We consider dark matter annihilation in the gravitational field of noncommutative black holes. At final stage of evaporation, we hypothesize the existence of a thermal equilibrium state composed of a burning black hole relics fueled by dark matter accretion. We discuss its possible connection to primordial black holes and early universe.
Futoshi Yagi Korea Institute for Advanced Study 5d supersymmetric gauge theories with 6d UV fixed points
We discuss a class of five dimensional $\mathcal{N}=1$ supersymmetric gauge theories which has six dimensional $\mathcal{N}=(1,0)$ superconformal field theories as ultraviolet fixed points. We find various non trivial properties of these theories by using type IIB brane web diagram including orientifold planes. Especiailly, we see that various different 5d theories have identical UV fixed point.

August 11 (Thu)

Morning Session 1 (9:00-10:10)
Yu Nakayama* Rikkyo University Applied conformal bootstrap*
I will review some physical applications of numerical conformal bootstrap. In particular, I will focus on various controversies in theoretical physics such as the order of chiral phase transition in QCD or VBS-Neel phase transition in quantum spin systems. In many situations, our numerical results dash the hopes of emergent symmetries proposed in the literature.
Morning Session 2 (10:40-11:55)
Hirotaka Hayashi Tokai University 5-brane webs and 6d SCFTs
5-brane webs in type IIB string theory is a very useful tool to study various properties of 6d SCFTs. In particular, 5-brane webs realize new 5d supersymmetric gauge theories whose UV completion is given by 6d SCFTs. One important example is a 5d SU(3) gauge theory with 10 flavors whose UV completion is a 6d $D_5$-type minimal conformal matter theory. Moreover, the 5-brane web also reveals that the 5d SU(3) gauge theory with 10 flavors is dual to a 5d Sp(2) gauge theory with 10 flavors. In this talk, we give a quantitative evidence for the 5d-6d correspondence as well as the 5d UV duality by explicitly comparing their 5d partition functions and the elliptic genus of the 6d SCFT. We find that the 5-brane web encodes the information of the partition function of the 5d SU(3) gauge theory with 10 flavors and also the duality map. The precise agreement among the partition functions and the elliptic genus has been checked until certain order.
Hidehiko Shimada Okayama Institute for Quantum Physics Tensionless string field theory and N=(2,0) theory in six-dimensions
We consider a second quantised formulation of supersymmetric tensionless strings in six dimensions. We discuss its interpretation as a candidate for the formulation of the six-dimensional $\mathcal{N}=(2,0)$ superconformal theory. The talk will be based on a work done in collaboration with Sudarshan Ananth(IISER Pune), Stefano Kovacs(Dublin IAS), Yuki Sato(Chulalongkorn University).
Masayuki Fukuda University of Tokyo Coherent states in spherical DAHA and qq-character for 5D Super Yang-Mills
We study some properties of coherent states (Gaiotto state and intertwiner between two modules) in the quantum $\mathcal{W}_{1+\infty}$ algebra, which is also known under various names, Ding-Iohara, Miki and quantum toroidal $\widehat{\mathfrak{gl}} (1)$ algebra. With its properties, we derive the qq-character for 5d quiver gauge theories which defines the quantum Seiberg-Witten curve.
Afternoon Session 1 (13:25-14:40)
Kazunobu Maruyoshi Seikei University A 'Lagrangian' for the Argyres-Douglas theory and superconformal index
We find a four-dimensional N=1 gauge theory which flows to the N=2 Argyres-Douglas theory $H_0$ in the infrared up to extra free chiral multiplets. From this description we compute the full superconformal index of the $H_0$ theory and find agreements with the known results in special limits. The gauge theory description is obtained from certain N=1 deformation of the N=2 SU(2) gauge theory with 4 fundamental hypermultiplets. Indeed this deformation procedure can be applied to any N=2 SCFT with non-Abelian flavor symmetry. In general, we observe that the deformation of a particular class of N=2 SCFTs causes the flow where the supersymmetry is enhanced to N=2 in the infrared.
Matthew Buican Queen Mary University of London Conformal Manifolds in Four Dimensions and Chiral Algebras
Any $\mathcal{N}=2$ superconformal field theory (SCFT) in four dimensions has a sector of operators related to a two-dimensional chiral algebra containing a Virasoro sub-algebra. Moreover, there are well-known examples of isolated SCFTs whose chiral algebra is a Virasoro algebra. In this note, we consider the chiral algebras associated with interacting $\mathcal{N}=2$ SCFTs possessing an exactly marginal deformation that can be interpreted as a gauge coupling (i.e., at special points on the resulting conformal manifolds, free gauge fields appear that decouple from isolated SCFT building blocks). At any point on these conformal manifolds, we argue that the associated chiral algebras possess at least three generators. In addition, we show that there are examples of SCFTs realizing such a minimal chiral algebra: they are certain points on the conformal manifold obtained by considering the low-energy limit of type IIB string theory on the three complex-dimensional hypersurface singularity $x_1^3+x_2^3+x_3^3+\alpha x_1x_2x_3+w^2=0$. The associated chiral algebra is the $\mathcal{A}(6)$ theory of Feigin, Feigin, and Tipunin. As byproducts of our work, we argue that (i) a collection of isolated theories can be conformally gauged only if there is a SUSY moduli space associated with the corresponding symmetry current moment maps in each sector, and (ii) $\mathcal{N}=2$ SCFTs with $a\ge c$ have hidden fermionic symmetries (in the sense of fermionic chiral algebra generators).
Takahiro Nishinaka Yukawa Institute for Theoretical Physics On 4d rank-one N=3 superconformal field theories
We study the properties of 4d N=3 superconformal field theories whose rank is one, i.e. those that reduce to a single vector multiplet on their moduli space of vacua. We find that the moduli space can only be of the form $C^3/Z_k$ for k=1,2,3,4,6, and that the supersymmetry automatically enhances to N=4 for k=1,2. In addition, we determine the central charges a and c in terms of k, and construct the associated 2d chiral algebras, which turn out to be exotic N=2 supersymmetric W-algebras. This talk is based on arXiv:1602.01503 in collaboration with Yuji Tachikawa.
Afternoon Session 2 (14:55-16:10)
Hisayoshi Muraki KEK Kahler structures in Matrix Geometry
Recently, a method of defining classical spaces with a use of information of matrices has been proposed in arXiv:1503.01230. The method utilizes the coherent states for N by N hermitian matrices and identifies those states with points on the classical space under the large N limit. In arXiv:1603.09146, the Kahler structure is obtained by the quantum states in the large N limit. When we discuss geometric structures in the finite N regime, the Dirac operators plays a role. I will give you an overview of the method and discuss how the Dirac operator works. This talk is based on works in collaboration with Goro Ishiki and Takaki Matsumoto (Univ. of Tsukuba).
Naoya Umeda Kyoto University Critical behavior of triangle-hinge models
Triangle-hinge models [arXiv:1503.08812] are introduced to describe worldvolume dynamics of membranes. The Feynman diagrams consist of triangles glued together along hinges and can be restricted to tetrahedral decompositions in a large N limit. We find that there are integration contours for which the integrations of dynamical variables are finite. We further find that the models have critical points by numerical simulations. It is highly expected that the models have well-defined continuum limits.
Tsunehide Kuroki National Institute of Technology, Kagawa College Correlation functions at arbitrary genus in noncritical superstring theory
In the previous study, we found that a supersymmetric double-well matrix model reproduces several kinds of, and infinitely many two-point functions at tree level in noncritical superstring theory in two dimensions. This strongly suggests that the former gives nonperturbative formulation of the latter. Thus assuming this, we studied nonperturbative aspects of the superstring theory such as spontaneous breaking of supersymmetry. In this talk, in order to present further evidence of our claim, we present explicit form of several correlation functions at arbitrary genus in the matrix model side. We point out that the Nicolai mapping and exact results in the random matrix theory play important roles in the derivation. We also discuss how resurgence works in our higher genus results.
Afternoon Session 3 (16:25-17:40)
Ryo Yokokura Keio University Component versus Superspace Approaches to D=4, N=1 Conformal Supergravity
We show the equivalence between the superspace formulation and the conventional component field approach based on the superconformal tensor calculus of N=1 conformal supergravity in four dimensions, and that superspace formulation does not have the restriction previously discussed by Kugo and Uehara. We present also the correspondences of the conformal multiplets.
Yuki Yokokura RIKEN Quantum mechanical construction of energy-momentum tensor and the interior structure of black holes
We introduce a notion of local vacuum state and construct energy-momentum tensor operator in a covariant way. Evaluating its expectation value in the self-consistent metric of evaporating black holes, we investigate the interior structure and discuss the information problem.
Nobuyoshi Ohta Kindai University Renormalization Group Equation for $f(R)$ gravity on a hyperbolic space
As one of the promising approaches to the quantum gravity, we discuss the asymptotic safety program. In particular we derive the functional renormalization group equation for the gravitational effective average action in an $f(R)$ truncation on hyperbolic space using exponential parametrization of the metric and study their properties. We find various exact solutions in the theory and compare the results with those on the positive-curvature space.

August 12 (Fri)

Morning Session 1 (9:00-10:10)
Sungjay Lee* Korea Institute for Advanced Study Bootstrapping Pure Quantum Gravity in AdS3*
It is an interesting problem to understand whether the three-dimensional pure gravity can exist as a quantum theory. The extremal conformal field theories of central charge c=24k have been conjectured to be dual to the three-dimensional pure quantum gravity with negative cosmological constant. The extremal CFTs should have a large gap in the spectrum proportional to the central charge. Although the extremal CFT is known to exist for k=1, it is not entirely clear whether one can actually construct the extremal CFTs for k>1. We use the numerical bootstrap to investigate the existence of the extremal CFTs having a sparse spectrum of states at low energies.
Morning Session 2 (10:40-11:55)
Heng-Yu Chen National Taiwan University Quantum Integrable Systems from Conformal Blocks
In this talk, we extend the striking connections between quantum integrable systems and conformal blocks recently found in several directions. First, we explicitly demonstrate that the action of quartic conformal Casimir operator on general d-dimensional scalar conformal blocks, can be expressed in terms of certain combinations of commuting integrals of motions of the two particle hyperbolic BC2 Calogero-Sutherland system. The permutation and reflection properties of the underlying Dunkl operators play crucial roles in establishing such a connection. Next, we show that the scalar superconformal blocks in SCFTs with four and eight supercharges and suitable chirality constraints can also be identified with the eigenfunctions of the same Calogero-Sutherland system, this demonstrates the universality of such a connection. Finally, we observe that the so-called "seed" conformal blocks for constructing four point functions for operators with arbitrary space-time spins in four dimensional CFTs can also be linearly expanded in terms of Calogero-Sutherland eigenfunctions.
Ryo Suzuki ICTP-SAIFR Average anomalous dimensions in N=4 SYM
We investigate an interplay between conformal bootstrap and large $N_c$ limit, by asking how to extract non-planar data from the planar four-point functions. By taking a short-distance limit of the four-point functions of ${\cal N}=4$ super Yang-Mills at large $N_c$, we obtain a sum of anomalous dimensions averaged over the operators with the same quantum numbers. By counting all possible operators to be averaged, we isolate the non-planar information of the spectrum. This is a joint work with Yusuke Kimura (Okayama Institute for Quantum Physics).
Hideki Kyono Kyoto University Supercoset construction of Yang-Baxter deformed AdS5xS5 backgrounds
Yang-Baxter deformation is a systematic way to study integrable deformations of non-linear sigma models in two dimensions. One of the most interesting examples is deformations of type IIB superstring theory on the AdS5 × S5 background. So far, some well-known string backgrounds concerned with the AdS/CFT correspondence were obtained as Yang-Baxter deformations of AdS5 × S5. The metric and the B-field can be derived directly from the deformed action. Furthermore, the remaining fields including the Ramond-Ramond (R-R) fields and the dilaton were recently derived by performing the supercoset construction for some r-matrices. Some examples of the deformed backgrounds satisfy the equations of motion of type IIB supergravity. In general, however, they are not the solutions of the supergravity in the usual sense, but it is conjectured that they would satisfy “generalized’’ equations of motion, which are modified to keep only the scale invariance on the string world-sheet theory rather than conformal invariance. This conjecture indicates that the classical r-matrices satisfying the CYBE correspond to the gravity solutions in the weaker sense, and the relation may be called the gravity/CYBE correspondence.