YITP Workshop
Strings and Fields 2019

August 19 (Mon) - August 23 (Fri), 2019

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

Program

Invited talks including overviews are marked with ^*.
Length of talks: 60 mins for invited talk and 20 mins for short talk.
At the beginning of each poster session, there are 1-min talks by the presenters of the posters.
Individual abstracts can be shown by clicking/touching the entry.
You can also .

August 19 (Mon)
Afternoon Session 1 (12:45-13:55)
Koutarou Kyutoku	Kyoto University	Gravitational-wave and multi-messenger astronomy^*
After the first direct detection in 2015, gravitational-wave astronomy with binary-black-hole mergers has become daily science. While multi-messenger (i.e., gravitational and electromagnetic) detection of binary neutron stars has so far been limited to a single event in 2017, the number of gravitational-wave candidates from binary-neutron-star mergers is increasing in the current observing run of the LIGO-Virgo Collaboration. Multi-messenger astronomy may also become a routine in the near future. In this talk, I will review the current status and future prospects of gravitational-wave and multi-messenger astronomy.
Afternoon Session 2 (14:15-15:30)
Miok Park	Korea Institute for Advanced Study	QuasilocalSmarr Relations
A quasilocal Smarr relation is obtained from Euler's theorem for n-dimensional spacetimes and it is checked through several examples by calculating quasilocal variables using the Brown-York quasilocal formalism, along with Mann-Marolf counterterms. To find the entropy in the quasilocal frame, we define a quasilocal free energy from the Euclidean gravity action with a Tolman temperature. In which the entropy obtained through this method agrees with the usual Bekenstein- Hawking entropy.
Yuki Yokokura	RIKEN	Black Hole as a Quantum Field Configuration
We study quantum states of black holes in field theory. First, we consider time evolution of a spherical collapsing matter, including the back reaction of particle creation that occurs in the time-dependent spacetime. As a result, a compact high-density star with no horizon or singularity is formed and eventually evaporates. This is a quantum black hole. In this talk, we investigate the metric $g_{\mu\nu}$ and state $\|\psi \rangle$ expressing this picture and satisfying the semi-classical Einstein equation $G_{\mu\nu}=8\pi G \langle \psi\|T_{\mu\nu}\|\psi \rangle$. We also discuss how the entropy area law appears in this view.
Nobuyoshi Ohta	Kindai University	Asymptotic Safety and the Dimension of the Critical Surface
After brief summary of the asymptotic safety approach to quantum gravity, we study Einstein theory plus cosmological constant, scalar curvature square and Ricci curvature square on general backgrounds, and discuss what is the dimension of critical surface, which is the important clue to the formulation of nonperturbatively renormalizable theory of gravity.
Afternoon Session 3 (15:45-17:00)
Takaaki Ishii	Kyoto University	Black resonators and geons in AdS$_5$
Rotating black holes exhibit superradiant instability in AdS spacetime. Black hole solutions incorporating the backreaction of the instability have been recently found and called black resonators. I will talk about constructing a class of black resonators emerging from the onset of a superradiant instability of the Myers-Perry-AdS black hole with equal angular momenta in 5D AdS spacetime.
Masataka Matsumoto	Chuo University	Non-equilibrium Phase Transitions and Spontaneous Symmetry Breaking in Holography
The holographic probe brane system exhibits the nonlinear conductivity in the presence of an electric field. Associated with this nonlinearity, the system shows the current-driven non-equilibrium phase transition. We study this non-equilibrium phase transition in the case of massless quark. We find that spontaneous symmetry breaking occurs if we apply not only an electric field but a magnetic field. We also analyze the critical phenomena associated with this non-equilibrium phase transition.
Shuichi Yokoyama	Yukawa Institute for Theoretical Physics	Holographic geometry for non-relativistic systems emerging from generalized flow equations
I will speak about the holographic construction of bulk system incorporating a flow equation. In particular I will explain my recent work on the application of this framework to a generic non-relativistic CFT. The resulting geometry is a hybrid geometry of Lifshitz and Schrödinger spacetimes, which reduces to each of them by considering special non-relativistic models.
Afternoon Session 4 (17:15-18:30)
Yoshinori Matuso	Osaka University	Nuclear states and spectra in holographic QCD
A new method to study nuclear physics via holographic QCD is proposed. Multiple baryons in the Sakai-Sugimoto background are described by a matrix model which is a low energy effective theory of D-branes of the baryon vertices. We study the quantum mechanics of the matrix model and calculate the eigenstates of the Hamiltonian. The obtained states are found to coincide with known nuclear and baryonic states, and have appropriate statistics and charges. Calculated spectra of the baryon/nucleus for small baryon numbers show good agreement with experimental data. For hyperons, the Gell-Mann--Okubo formula is approximately derived. Baryon resonances up to spin 5/2 and isospin 5/2 and dibaryon spectra are obtained and compared with experimental data. The model partially explains even the magic numbers of light nuclei, N=2, 8 and 20.
Hiromasa Watanabe	University of Tsukuba	Partial Deconfinement
We argue the existence of “partially deconfined phase” in some SU(N) gauge theories, which is in between the confined and deconfined phases. We characterize this phase in terms of the Polyakov line phases and its distribution. Also, we study examples of theories in which the partially deconfined phase exists and find the relation to the Gross-Witten-Wadia transition. The partially deconfined phase is conjectured to be the counterpart of the small black hole phase in the context of the gauge/string duality. We discuss possible applications in this context.
Ryo Yokokura	KEK	Topological order in the color-flavor locked phase of (3+1)-dimensional U(N) gauge-Higgs system
We study a (3+1)-dimensional U(N) gauge theory with N-flavor fundamental scalar fields, whose color-flavor locked (CFL) phase has topologically stable non-Abelian vortices. The U(1) charge of the scalar fields must be Nk+1 for some integer k in order for them to be in the representation of U(N) gauge group. This theory has a Z$_{Nk+1}$ one-form symmetry, and it is spontaneously broken in the CFL phase, i.e., the CFL phase is topologically ordered if k is not 0. We also find that the world sheet of topologically stable vortices in CFL phase can generate this one-form symmetry.
August 20 (Tue)
Morning Session 1 (9:00-10:10)
Richard Szabo	Heriot-Watt University	The geometry of double field theory ^*
I will review recent progress in understanding the geometric realisations of doubled spacetimes as they occur in double field theory, and how they entail precise descriptions of T-duality and of non-geometric string backgrounds.
Morning Session 2 (10:30-11:45)
Yuta Sekiguchi	University of Bern	$O(d,d)$ transformations preserve classical integrability
In our recent paper [arXiv:1907.03759], we studied the action of global $O(d,d;\mathbb{R})$ deformations on the Lax pairs of WZNW models using the doubled formalism. We explicitly constructed $O(d,d)$-deformed Lax pairs by applying the so-called O(d,d)-map to the undeformed but gauged Lax pairs. The conclusion is that any global $O(d,d;\mathbb{R})$ transformation preserves classical integrability, and the local conserved charges in the undeformed model should be mapped to the non-local ones after the deformation as argued in [arXiv:0711.0707]. In this talk, after showing some motivation of studying the $O(d,d)$ transformations from the angle of integrability, I will give a brief review of Lax pairs and unpackage the doubled formalism to learn the $O(d,d)$ map. Then as a concrete and small example I plan to briefly present how to construct $O(2,2)$-deformed (current-current deformed) Lax pairs starting from the WZNW model on the three-sphere with non-zero $H$-flux.
Hiroaki Matsunaga	Czech Academy of Sciences	Light-cone string field theory from covariant string field theory
We extract a light-cone string field theory from Witten’s covariant string field theory on the basis of the homological perturbation. The covariant string field splits into the light-cone string field and trivial excitations of BRST quartets: The latter generates the gauge symmetry and covariance. A new light-cone theory is obtained by path-integrating it out from the covariant theory. We show that the process of path-integrating-out fields is described by the homological perturbation lemma (for A-infinity) and thus our new light-cone theory has the same tree-level amplitudes as the Witten theory.
Yuji Okawa	The University of Tokyo	Nonperturbative definition of closed string theory with holes in the world-sheet via open string field theory
In typical examples of the AdS/CFT correspondence, closed string theory with holes in the world-sheet is assumed to be equivalent in a low energy limit to closed string theory without holes in the world- sheet on a curved background such as $AdS_5 \times S^5$. In the case of the bosonic string, we claim that open string field theory on $N$ coincident D-branes can be used to provide a nonperturbative definition of such closed string theory with holes in the world-sheet based on the fact that the $1/N$ expansion of correlation functions of gauge-invariant operators reproduces the closed string perturbation theory with the moduli space of Riemann surfaces being precisely covered.
Morning Session 3 (12:00-13:15)
Matsuo Sato	Hirosaki University	Topological String Geometry
Perturbative string amplitudes are correctly derived from the string geometry theory, which is one of the candidates of a non-perturbative formulation of string theory. In order to derive non-perturbative effects rather easily from the theory, we formulate topological string geometry theory by restricting the string geometry theory to its topological sector. We derive the perturbative partition function of the topological string theory from fluctuations around a classical solution in the topological string geometry theory. Thanks to the twisting, the action of the topological string geometry theory can be written in a Q-exact form. Thus, we can utilize the localization method to obtain non-perturbative corrections to the topological string partition function.
Hikaru Ohta	SOKENDAI	Effective potential for revolving D-branes in superstring theory
We study the short distance behavior of the effective potential of open strings compute the one-loop partition function for the D-branes revolving around each other. I will explain how to compute the one-loop partition function of the open strings stretched between the revolving D-branes, from which we can extract the short-distance behavior of the effective potential.
Sota Hanazawa	Ibaraki University	Non-abelian extension of Supersymmetric DBI Equations in Pure Spinor Formulation
We have examined the BRS invariance of the open pure spinor superstring to derive the supersymmetric Dirac-Born-Infeld (DBI) equations of motion for a D$p$-brane. These equations are consistent with the supersymmetric DBI equations for a D9-brane obtained by Berkovits and Pershin. They also analyzed non-abelian backgrounds up to quadratic order in $\eta$, so-called boundary fermion, which is a world-volume fermion in the representation of the $SU(N)$ gauge subgroup. In this talk, we extend previous results to non-abelian DBI equations of motion for coincident D$p$-branes including all $\eta$'s.
Afernoon Session 1 (14:30-15:45)
Sheng-Hong Lai	National Chiao Tung University	The SL(K+3,C) Symmetry of the Bosonic String Scattering Amplitudes
We discover that the exact string scattering amplitudes (SSA) of three tachyons and one arbitrary string state, or the Lauricella SSA (LSSA), in the $26D$ open bosonic string theory can be expressed in terms of the basis functions in the infinite dimensional representation space of the $SL(K+3,% %TCIMACRO{\U{2102} }% %BeginExpansion \mathbb{C} %EndExpansion )$ group. In addition, we find that the $K+2$ recurrence relations among the LSSA discovered by the present authors previously can be used to reproduce the Cartan subalgebra and simple root system of the $SL(K+3,% %TCIMACRO{\U{2102} }% %BeginExpansion \mathbb{C} %EndExpansion )$ group with rank $K+2$. As a result, the $SL(K+3,% %TCIMACRO{\U{2102} }% %BeginExpansion \mathbb{C} %EndExpansion )$ group can be used to solve all the LSSA and express them in terms of one amplitude. As an application in the hard scattering limit, the $SL(K+3,% %TCIMACRO{\U{2102} }% %BeginExpansion \mathbb{C} %EndExpansion )$ group can be used to directly prove Gross conjecture, which was previously corrected and proved by the method of decoupling of zero norm states.
Ryota Kojima	SOKENDAI	Sign flip triangulation of the amplituhedron
In this talk, I will talk about the triangulation of the amplituhedron. To obtain higher point amplitude from the general amplituhedron, we need to triangulate it into a simple one. There is some way to triangulate the amplituhedron and some of this gives new representations of the amplitude. I will briefly explain the amplituhedron and its property, then I will talk about the new representation of the amplitude from the sign flip triangulation.
Sanefumi Moriyama	Osaka City University	Symmetry Breaking in Quantum Curves and Super Chern-Simons Matrix Models
M2-brane is one of the central topics in understanding non-perturbative effects in string theory. Recently it was proposed that multiple M2-branes on various backgrounds are described by various superconformal Chern-Simons theories, whose partition function reduces to a matrix model after applying the localization technique. These super Chern-Simons matrix models are known to correspond to quantum version of algebraic curves. From the viewpoint of symmetry, the algebraic curve of genus one, called the del Pezzo curve, enjoys symmetry of the exceptional algebra, while the super Chern-Simons matrix model is described by the free energy of topological strings on the del Pezzo background with the symmetry broken. In this talk, I introduce the quantum version of algebraic curves for our purpose of studying M2-branes and explain how studies of the symmetry aspects help in understanding M2-branes.
Poster Session 1 (16:00-18:30)
Yugo Abe	NIT, Miyakonojo College	S-matrix Unitarity in Higher Derivative gravity with matter
We investigate the ultraviolet (UV) behavior of two-scalar elastic scattering with graviton exchanges in higher curvature gravity theory. In the Einstein gravity, matter scattering is shown not to satisfy the unitarity bound in tree level at high energy. Among a few possible directions to the UV completion of Einstein gravity, string theory, modiﬁed gravity, inclusion of high-mass/high-spin states, we take $R_{\mu\nu}^2$ gravity coupled to matter. We show that the matter scattering with graviton interactions satisﬁes the unitarity bound at high energy, even with the negative norm states due to the higher order derivatives of metric components. The difference in this unitarity property of the two gravity theories is probably connected to that in another UV property, namely renormalizability property of the two.
Tomohiro Furukawa	Osaka City University	ABJM matrix model and two-dimensional Toda Lattice hierarchy
In the ABJM matrix model, the one point functions (one point functions of the half BPS Wilson loop in the ABJM theory) satisfy the Jacobi-Trudi identity.This fact suggest the existence of the integrable structure in the ABJM matrix model. We made it clear. In particular, the one point functions in the ABJM matrix model has the structure corresponding to the mKP hierarchy and the two point functions has the structure corresponding to the two- dimensional Toda lattice hierarchy.
Takuya Hirose	Osaka City University	Cancellation of One-loop Corrections to Scalar Masses in Yang-Mills Theory with Flux Compactification
We calculate one-loop corrections to the mass for the zero mode of scalar field in a six-dimensional Yang-Mills theory compactified on a torus with magnetic flux. It is shown that these corrections are exactly cancelled thanks to a shift symmetry under the translation in extra spaces. This result is expected from the fact that the zero mode of scalar field is a Nambu-Goldstone boson of the translational invariance in extra spaces.
Kenji Hotta	Hokkaido University	Creation of D9-brane--anti-D9-brane Pairs in Time Dependent Background
Recently, we have investitated Unruh effect for closed strings and for open strings on D9-brane--anti-D9-brane pairs, and discuss the creation of D9-brane--anti-D9-brane pairs for highly accelerated observers. In this talk, we consider a simple time dependent background, in which the spacetime becomes Minkowski spacetime in the far past and future, and investigate the Hawking-Unruh effect of open strings on D9-brane--anti-D9-brane pairs. We show that D9-brane--anti-D9-brane pairs are created in the far future. Then we propose that if there is an accelerated object or if the metric is time dependent, not only closed strings but also D9-brane--anti-D9-brane pairs are created around them. We also discuss the creation of D9-brane--anti-D9-brane pairs in the case of the black hole formation.
Shuta Ishigaki	Chuo University	Analysis of bound states in holographic conductors
The AdS/CFT correspondence is a powerful tool to analyze non-equilibrium systems. By using this correspondence, one can calculate the non-linear conductivity of a charged many-body system interacting with a heat bath. In some cases, the system shows a negative differential conductivity (NDC) in some parameter regions. NDC is often seen in strongly-correlated electron systems and it is a non-equilibrium phenomenon far from equilibrium. However, the mechanism of the NDC is not still understood completely. We analyze the bound states consisting of a charged particle and an anti-particle to explore the mechanism of the NDC. We find that the lifetime of the bound states grows as increasing the electric field in the NDC regions. This implies the bound states play an important role in the realization of the NDC. In our presentation we will explain the result and the interpretation.
Nahomi Kan	NIT, Gifu College	Accelerating cosmologies in an integrable model with　 noncommutative minisuperspace variables
We study classical and quantum noncommutative cosmology with a Liouville-type scalar degree of freedom. The noncommutativity is imposed on the minisuperspace variables through a deformation of the Poisson algebra. In this paper, we investigate the effects of noncommutativity of minisuperspace variables on the accelerating behavior of the cosmic scale factor. The probability distribution in noncommutative quantum cosmology is also studied and we propose a novel candidate for interpretation of the probability distribution in terms of noncommutative arguments.
Man Hea Kim	Kyungpook National University	The Operator Product Expansions in the N=4 Orthogonal Wolf Space Coset Model
Some of the operator product expansions (OPEs) between the lowest $SO(4)$ singlet higher spin-$2$ multiplet of spins $(2, \frac{5}{2}, \frac{5}{2}, \frac{5}{2}, \frac{5}{2}, 3, 3, 3, 3, 3, 3, \frac{7}{2}, \frac{7}{2}, \frac{7}{2}, \frac{7}{2}, 4)$ in an extension of the large ${\cal N}=4$ (non)linear superconformal algebra were constructed in the ${\cal N}=4$ superconformal coset $\frac{SO(N+4)}{SO(N) \times SO(4)}$ theory with $N=4$ previously. In this paper, by rewriting the above OPEs with $N=5$, the remaining undetermined OPEs are completely determined. There exist additional $SO(4)$ singlet higher spin-$2$ multiplet, six $SO(4)$ adjoint higher spin-$3$ multiplets, four $SO(4)$ vector higher spin-$\frac{7}{2}$ multiplets, $SO(4)$ singlet higher spin-$4$ multiplet and four $SO(4)$ vector higher spin-$\frac{9}{2}$ multiplets in the right hand side of these OPEs. Furthermore, by introducing the arbitrary coefficients in front of the composite fields in the right hand sides of the above complete 136 OPEs, the complete structures of the above OPEs are obtained by using various Jacobi identities for generic $N$. Finally, we describe them as one single ${\cal N}=4$ super OPE between the above lowest $SO(4)$ singlet higher spin-$2$ multiplet in the ${\cal N}=4$ superspace.
Smain Kouadik	Université de Médéa	Construction of Translation-invariant U(N) non commutative gauge model
We build a non commutative unitary gauge group model preserving translational invariance. It describes the interaction of Dirac eld with the Gauge eld. The interaction term is expanded as a power series resulting from the introduction of the inverse covariant derivative. The consistancy of the model is sustained by the fact that the Ward identity at the tree level holds
Yasunari Kurita	Kanagawa Institute of Technology	Thermodynamics of AdS$_3$ pure gravity : extremal CFTs vs. semiclassical gravity
The set of extremal CFTs is a candidate for AdS$_3$ pure quantum gravity, as suggested by Witten. We investigate thermodynamic properties of extremal CFTs in comparison with semiclassical gravity and find new phase transitions between BTZ and something unknown. It might indicate that they are not suitable for AdS$_3$ pure quantum gravity.
Ping Kwan Man	Waseda University	BI model - An Extension of Starobinsky model induced by SUGRA
Cosmological inflation is a powerful solution to the flatness and horizon problems at the beginning of the standard Big Bang scenario. So far, being motivated by modified gravity, Starobinsky model has been the most promising prediction of inflation that it satisfies all the observation data. On the other hand, supergravity (SUGRA) is the best model to unify gravity with particle physics beyond the Standard Model of elementary particles and beyond the Standard (ΛCDM) Model of cosmology. In this talk/ poster session, the integration between SUGRA and Starobinsky model will be shown, and the parameter scales in the SUGRA model required to integrate with Starobinsky model will also be discussed.
Tatsuya Mori	Tokyo Institute of Technology	Finite N corrections to the superconformal index of orbifold quiver gauge theories
We study the finite $N$ AdS/CFT correspondence between the Type IIB string theories on AdS$_5 \times S^5/\Gamma$ and quiver gauge theories. We assume that D3-branes wrapping on the three-cycles in the internal space give the finite $N$ corrections to the index. We calculate the index of wrapped D3-branes for each sector of wrapping numbers and get the non-trivial coincidence for leading finite $N$ corrections in comparison with the localization results from the gauge theory. For the comparison, we need to establish the relation between the wrapping numbers of D3-branes and the baryonic charges of operators in quiver gauge theories. In this poster, we explain the relation in detail.
Sota Nakajima	Osaka City University	Exponentially suppressed cosmological constant with enhanced gauge symmetry in heterotic interpolating models
A few nine-dimensional interpolating models with two parameters are constructed and the massless spectra are studied by considering compactification of heterotic strings on a twisted circle with Wilson line. It is found that there are some conditions between radius R and Wilson line A under which the gauge symmetry is enhanced. In particular, when the gauge symmetry is enhanced to $SO(18) \times SO(14)$, the cosmological constant is exponentially suppressed. We also construct a non- supersymmetric string model which is tachyon-free in all regions of moduli space and whose gauge symmetry involves $E_8$.
Yuta Nasuda	Tokyo University of Science	SUSY QM with Conditional Shape Invariance and the Solvability
Exactly solvable quantum mechanics (or SUSY QM) has extensively been studied for many years. It is known that the idea of shape invariance is the sufficient condition for exact solvability and is crucial for finding solutions. Recently, a powerful way of constructing solutions has proposed where the modified concept of shape invariance is applied. We present the prescription and thoroughly discuss the mathematical implications.
Kenta Shiozawa	Kitasato University	Doubled Aspects of Vaisman Algebroid and Gauge Symmetry in Double Field Theory
The metric algebroid proposed by Vaisman (the Vaisman algebroid) governs the gauge symmetry algebra generated by the C-bracket in double field theory (DFT). We show that the Vaisman algebroid is obtained by an analogue of the Drinfel’d double of Lie algebroids. Based on a geometric realization of doubled space-time as a para-Hermitian manifold, we examine exterior algebras and a para-Dolbeault cohomology on DFT and discuss the structure of the Drinfel’d double behind the DFT gauge symmetry. Similar to the Courant algebroid in the generalized geometry, Lagrangian subbundles $(L,\tilde{L})$ in a para-Hermitian manifold play Dirac-like structures in the Vaisman algebroid. We find that an algebraic origin of the strong constraint in DFT is traced back to the compatibility condition needed for $(L,\tilde{L})$ be a Lie bialgebroid. The analysis provides a foundation toward the “coquecigrue problem” for the gauge symmetry in DFT.
Tatsuya Sugimoto	Yukawa Institute for Theoretical Physics	Closed string field theory with cyclic L-infinity structure
We construct the gauge-invariant action for heterotic and type II string field theories. We give a construction of string products that realizes the cyclic L-infinity structure.
Inori Ueba	Kobe University	Extended supersymmetric quantum mechanics from symmetries in higher dimensional Dirac action
In this talk, we discuss the structure of N-extended supersymmetric quantum mechanics with central charges hidden in the 4D mass spectrum of the higher dimensional Dirac action. This supersymmetric quantum mechanics results from symmetries in curved extra dimensions, and the supercharges tell us a relationship among the Kaluza-Klein mode functions with degenerate 4D mass eigenvalues due to the degrees of freedom of the higher dimensional spinor. We also show that the mode functions correspond to the BPS states in this supersymmetry algebra.
Kazushi Yamashiro	Shizuoka University	Relationship between information geometry for renormalization group and bulk geometry in gravity dual
In this poster, we study relationship between information geometry for renormalization group and bulk geometry in gravity dual. On the QFT side, the information metric in a theory perturbated from a conformal field theory is calculated along the RG flow. On the other hand, by following the GKP-Witten relation, we find the corresponding classical solution on the gravity side that asymptotically reduce to the AdS solution. Finally, we find relationship between this information metric and the geometry described by the classical solution.
August 21 (Wed)
Morning Session 1 (9:00-10:10)
Guilherme L. Pimentel	University of Amsterdam	Bootstrapping Inflationary Fluctuations^*
In flat space, four point scattering amplitudes at weak coupling can be fully determined from Lorentz symmetry, unitarity and causality. The resulting scattering amplitude depends on model details only through coupling constants and the particle content of the theory. I will show how the analogous story works in the case of inflationary fluctuations. I will present explicit expressions for weakly coupled inflationary three and four-point functions, whose shapes depend on the field content of the theory, and do not depend on the specific inflationary model, as long as the fluctuations minimally break de Sitter symmetry. This ``cosmological bootstrap” is a first step towards classifying all possible shapes of primordial non-gaussianity, which can be searched for in experimental data. If time permits, I will also present results for cosmological correlation functions of spinning fields.
Morning Session 2 (10:30-11:45)
Suro Kim	Kobe University	Heavy spinning particles from signs of primordial non-Gaussianities
Within the so-called cosmological collider program, the non-analytic behavior of primordial non-Gaussianities has been studied as a probe of particles near the Hubble scale, analogously to the resonance signal in particle colliders. On the other hand, it has not been explored well how to probe particles heavier than the Hubble scale. In this talk, to enlarge the scope of the cosmological collider, we demonstrate that the signs of Wilson-coefficients of the inflaton effective couplings can be used to read off spins of such heavy particles. Then, we discuss how to determine the signs of the Wilson-coefficients using cosmological observations, focusing on the analytic part of the primordial non-Gaussianities.
Yermek Aldabergenov	Chulalongkorn University	Unified models of inflation, dark energy, and high-scale SUSY breaking
I review recent developments in N=1 supergravity-based models of Starobinsky-like inflation, dark energy (in the form of the cosmological constant), and high-scale SUSY breaking. The models utilize SU(1,1)/U(1) Kahler manifolds with Polonyi-type superpotentials, and alternative FI terms -- that do not require gauging of R-symmetry -- for de Sitter uplift. In some cases the models contain superheavy dark matter candidates as well.
Siyi Zhou	The Hong Kong University of Science and Technology	String Regge trajectory on de Sitter space and implications to inflation
We study the spectrum of semiclassical rotating strings on de Sitter space and its consistency, generalizing the Gubser-Klebanov-Polyakov (GKP) string on anti-de Sitter space. Even though a naive extrapolation of the linear Regge trajectory on flat space implies a violation of the Higuchi bound (a unitarity bound on the mass of higher-spin particles in de Sitter space), the curved space effects turn out to modify the trajectory to respect the bound. Interestingly, we find that there exists a maximum spin for each Regge trajectory as a consequence of accelerated expansion, which is helpful to make the spectrum consistent with the Higuchi bound, but at the same time it could be an obstruction to stringy UV completion based on an infinite higher-spin tower. By pushing further this observation, we demonstrate that the vacuum energy $V$ inflating the universe has to be bounded by the string scale $M_s$ as $V\lesssim M_s^4$, if UV completion is achieved by the leading Regge trajectory. Its application to inflation at the early universe implies an upper bound on the tensor-to- scalar ratio, $r\lesssim 0.01\times(M_s/10^{16} \text{GeV})^{4}$, which is within the scope of the near future CMB experiments.
Morning Session 3 (12:00-12:50)
Nobuyuki Matsumoto	Kyoto University	Stochastic processes of matrix models and the emergence of quantum spacetime
Towards formulating quantum gravity, we discuss how spacetime emerges from randomness. In [Fukuma, NM, Umeda [arXiv:1705.06097]], we defined for a given stochastic process 'the distance between configurations', which enumerates the difficulty of transition and introduces a geometry to the stochastic system. In this talk, we discuss the geometry described by stochastic processes of matrix models by identifying the eigenvalues as spacetime coordinates. We show that the large N limit gives a stochastic system of one eigenvalue moving in the background where other eigenvalues condensate. We investigate the geometry of this one-eigenvalue stochastic system, and argue that this corresponds to the classical geometry probed by a D-instanton in noncritical string theory. This talk is based on ongoing work with M. Fukuma (Kyoto University).
Kento Sugiyama	Shizuoka University	Hermitian matrix model with cusp potential
In this talk, we investigate zero and one dimensional Hermitian matrix models with cusp potentials at large N. We show that large N phase transitions in these models are quite different from the third order phase transitions in the ordinary polynomial potential cases. Particularly the zero dimensional matrix models exhibit unexpected behaviors.
Afternoon Session 1 (14:05-15:15)
Pablo Soler	Heidelberg University	Swampland Conjectures ^*
An very large number of four dimensional effective field theories can be obtained from compactifications of string theory, forming a set known as the landscape of string theory. It has been suggested that, beyond this landscape, there exist consistent-looking effective field theories that cannot be consistently embedded into UV complete theories of quantum gravity, in particular into string theory. They are said to belong to the swampland. In this talk, I will describe some of the conjectures that define the swampland (weak gravity, distance, de-Sitter and anti-de-Sitter conjectures) and some of their phenomenological implications.
Afternoon Session 2 (15:35-16:50)
Yun-Long Zhang	Yukawa Institute for Theoretical Physics	Hyperbolic field space and swampland conjecture for DBI scalar
We study a model of two scalar fields with a hyperbolic field space and show that it reduces to a single-field Dirac-Born-Infeld (DBI) model in the limit where the field space becomes infinitely curved. We apply the de Sitter swampland conjecture to the two-field model and take the same limit. It is shown that in the limit, all quantities appearing in the swampland conjecture remain well-defined within the single-field DBI model. Based on a consistency argument, we then speculate that the condition derived in this way can be considered as the de Sitter swampland conjecture for a DBI scalar field by its own. The condition differs from those proposed in the literature and only the one in the present paper passes the consistency argument.
Yoshinori Honma	Meiji Gakuin University	Distributions of non-supersymmetric flux vacua in Type IIB/F-theory compactifications
We examine vacuum structures of effective theories of moduli fields in the frameworks of Type IIB and F-theory ﬂux compactiﬁcations. Imposing the no-scale structure for the volume modulus, for two explicit examples we numerically investigate distributions of a huge number of local minima of effective potential in the complex structure and dilaton directions in moduli fields. Our results for distributions of non-supersymmetric minima exhibit an interesting behavior about string coupling dependence of the vacuum energy. This talk is based on a collaboration with H. Otsuka (KEK).
Hajime Otsuka	KEK	Landscape of four-dimensional F-theory flux vacua
We search for the supersymmetric and non-supersymmetric vacua in F-theory flux compactifications. By checking the distributions of both vacua against the Ashok-Douglas formula, we count the number of vacua and the size of supersymmetry breaking in the global F-theory context. This work is based on a collaboration with Y. Honma (Meiji Gakuin university).
Afternoon Session 3 (17:05-18:20)
Nakwoo Kim	Kyung Hee University	Solving Mass-deformed Holography Perturbatively
We study supergravity BPS equations which correspond to mass- deformation of some representative AdS/CFT examples. The field theory of interest are N=4, D=4 super Yang-Mills, the ABJM model in D=3, and the Brandhuber-Oz fixed point in D=5. For these gauge theories the free energy with mass terms for matter multiplets is calculable in large-N limit using supersymmetric localization technique. We suggest a perturbative method to solve the supergravity equations. For the dual of mass-deformed ABJM model we reproduce the known exact solutions. For the mass-deformed Brandhuber-Oz theory our method gives the holographic free energy in analytic form. For N=2* theory our result is in good agreement with the localization result.
Hidenori Fukaya	Osaka University	Mathematical proof for "physicist-friendly" reformulation of Atiyah- Patodi-Singer index
The Atiyah-Patodi-Singer index theorem describes the bulk-edge correspondence of symmetry protected topological insulators. The mathematical set-up for this theorem is, however, not directly related to the physical fermion system, as it imposes on the fermion fields a non-local boundary condition known as the "APS boundary condition" by hand, which is unlikely to be realized in the materials. In 2017, we showed that the same integer as the APS index can be obtained from the eta-invariant of the domain-wall Dirac operator. In this work, we invite three mathematicians to our group and prove that this correspondence is not a coincidence but generally true. This work is in collaboration with M.Furuta, S.Matsuo, T.Onogi, Yamaguchi and Yamashita.
Naoki Kawai	Osaka University	Atiyah-Patodi-Singer index theorem on a lattice
Atiyah-Singer index theorem on a lattice without boundary is well understood owing to the seminal work by Hasenfratz. But its extension to the system with boundary ( the so-called Atiyah-Patodi-Singer index theorem), which surprisingly plays a crucial role in T-anomaly cancellation between bulk- and edge- modes in 3+1 dimensional topological matters, is known only in the continuum theory and no lattice realization has been made so far. In this work, we try to non-perturbatively define an alternative index from the lattice domain-wall fermion in 3+1 dimensions. We will show that this new index in the continuum limit, converges to the Atiyah- Patodi-Singer index defined on a manifold with boundary, which coincides with the surface of the domain-wall. This work is collaboration with Fukaya, Matsuki, Mori, Onogi, and Yamaguchi.
August 22 (Thu)
Morning Session 1 (9:00-10:10)
Kentaroh Yoshida	Kyoto University	TTbar deformation and holography ^*
In recent years, inspired by Sasha Zamolodchikov's pioneering work, TTbar deformation (more specifically, deformation with the determinant of the energy-momentum tensor) had been nergetically studied. In particular, for the TTbar deformation of 2D quantum field theory, interesting properties have been understood beyond conformal symmetry or integrability. In this talk, I will start with an elementary explanation of the TTbar deformation and outline some results for the TTbar deformation in the context of AdS/CFT.
Morning Session 2 (10:30-11:45)
Mitsuhiro Nishida	Gwangju Institute of Science and Technology	Entanglement and Renyi Entropy of Multiple Intervals in $T\overline{T}$-Deformed CFT and Holography
We study the entanglement entropy (EE) and the Renyi entropy (RE) of multiple intervals in two-dimensional $T\overline{T}$-deformed conformal field theory (CFT) at finite temperature by field theoretic and holographic methods. First, by the replica method with the twist operators, we construct the general formula of the RE and EE up to the first order of a deformation parameter. By using our general formula, we show that the EE of multiple intervals for a holographic CFT is just a summation of the single interval case even with the small deformation. This is a non-trivial consequence from the field theory perspective, though it may be expected by the Ryu-Takayanagi formula in holography. However, the deformed RE of the two intervals is a summation of the single interval case only if the separations between the intervals are big enough. It can be understood by the tension of the cosmic branes dual to the RE. We also study the holographic EE for single and two intervals with an arbitrary cut-off radius (dual to the $T\overline{T}$ deformation) at any temperature. We confirm our holographic results agree with the field theory results with a small deformation and high temperature limit, as expected. For two intervals, there are two configurations for EE: disconnected ($s$-channel) and connected ($t$-channel) ones. We investigate the phase transition between them as we change parameters: as the deformation or temperature increases the phase transition is suppressed and the disconnected phase is more favored.
Suguru Okumura	Kyoto University	Gravitational perturbations as $T\bar{T}$-deformations in 2D dilaton gravity systems
We consider gravitational perturbations of 2D dilaton gravity systems and show that these can be recast into $T\bar{T}$- deformations (at least) under certain conditions, where T means the energy-momentum tensor of the matter field coupled to a dilaton gravity. In particular, the class of theories under this condition includes a Jackiw-Teitelboim (JT) theory with a negative cosmological constant including conformal matter fields. This is a generalization of the preceding work on the flat-space JT gravity by S. Dubovsky, V. Gorbenko and M. Mirbabayi [arXiv:1706.06604].
Tomoki Nosaka	Korea Institute for Advanced Study	Quantum chaos transition in a two-site SYK model dual to an eternal traversable wormhole
Some quantum chaotic system has variant chaoticity depending on the temperature or the coupling constants, and enjoys a sharp chaos/integrable transition. To identify the gravitational phenomena corresponding to this transition, when the system has a gravity dual, we studied the chaos of a deformation of the SYK model proposed by [arXiv:1804.00491] which is dual to global AdS$_2$ geometry. As a result, we obtain an evidence indicating that the chaos/integrable transition is dual to the Hawking-Page transition.
Morning Session 3 (12:00-13:15)
Lento Nagano	The University of Tokyo	Interface entropy in 4d N=2 SCFTs
We construct a codimension-one defect (i.e., interface, or domain wall) in a 4d N=2 SCFT. We then define its entropy as an entanglement entropy and compute it via SUSY localization. We show that the interface entropy can be expressed in terms of a particular linear combination of analytically continued Kahler potentials called Calabi's diastasis, as conjectured in arXiv:1805.09981 by Goto and Okuda. The ambiguity in each Kahler potential due to Kahler transformations (equivalently the ambiguity due to finite counterterms in the partition functions that we use to express the interface entropy) cancels out in this combination.
Yuya Kusuki	Yukawa Institute for Theoretical Physics	Light cone bootstrap in 2D CFTs
We utilize the light-cone bootstrap technique to probe two- dimensional conformal field theories (CFTs) dual to quantum gravity theories in AdS${}_3$ (i.e., holographic CFTs). We show that the twist spectrum at large spin can be realized by the fusion rules of the {\it Liouville CFT}, which is the two- dimensional counterpart of the statement that the twist spectrum in any higher-dimensional CFTs can be approximated by that of a generalized free field theory in that limit. A key tool is the fusion matrix. We want to emphasize that besides solving the bootstrap equation, there is a number of other applications of our fusion matrix approaches. We show some simple examples to apply our method, such as evaluating entanglement entropy and out of time ordered correlator.
Hiroshi Isono	Chulalongkorn University	Momentum space approach to crossing symmetric conformal correlators
The crossing-symmetric basis of conformal four-point functions, introduced by Polyakov in 1974, enjoys explicit crossing symmetry while the consistency with operator product expansion is obscured, offering an alternative approach to conformal bootstrap. Polyakov originally defined this basis by requiring consistent factorisation, inspired by the similar property of scattering amplitudes. In this talk, we revisit Polyakov's original approach and complete the explicit construction of the crossing-symmetric basis in momentum space, along with our recent findings about analytic expressions of conformal three-point functions with spinning operators in momentum space.
Afternoon Session 1 (14:30-15:45)
Zhan-Feng Mai	Center for Quantum Joint Studies, School of Science Tianjin University	Holographic OPE Coefficients from AdS Black Holes with Matters
We study the OPE coefficients $c_{\Delta, J}$ for heavy-light scalar four-point functions, which can be obtained holographically from the two-point function of a light scalar of some non-integer conformal dimension $\Delta_L$ in an AdS black hole. For a pure gravity black hole, we find an inconsistency, namely $c_{d,0}\neq 0$ in $d>4$. This motivates us to consider black holes involving matter fields as well. We first consider general charged AdS black holes and we give some explicit low-lying examples of the OPE coefficients. We also obtain the recursion formula for the lowest-twist OPE coefficients with at most two current operators. For integer $\Delta_L$, although the OPE coefficients are not fully determined, we set up a framework to read off the coefficients $\gamma_{\Delta,J}$ of the $\log(z\bar{z})$ terms that are associated with the anomalous dimensions of the exchange operators and obtain a general formula for $\gamma_{\Delta,J}$. We then consider charged black holes in gauged supergravity STU models in $D=5$ and $D=7$, and their higher-dimensional generalizations. The scalar fields in the STU models are conformally massless, dual to light operators with $\Delta_L=d- 2$. We obtain the linear perturbation of such a scalar in the STU charged AdS black holes and obtain the explicit OPE coefficient $c_{d-2,0}$. The inconsistency of $c_{d,0}\ne 0$ however persists in all above examples for $d>4$. Finally, we analyse the asymptotic properties of scalar hairy AdS black holes and show how this inconsistency can be resolved in these backgrounds.
Takahiro Uetoko	Ritsumeikan University	Rectangular W-algebras of types so(M) and sp(2M) and dual coset CFTs
We examine rectangular W-algebras with $so(M)$ or $sp(2M)$ symmetry, which can be realized as the asymptotic symmetry of higher spin gravities with restricted matrix extensions. We compute the central charges of the algebras and the levels of $so(M)$ or $sp(2M)$ affine subalgebras by applying the Hamiltonian reductions of $so$ or $sp$ type Lie algebras. For simple cases with generators of spin up to two, we obtain their operator product expansions by requiring the associativity. We further claim that the W-algebras can be realized as the symmetry algebras of dual coset CFTs and provide several strong supports.
Takahiro Nishinaka	Ritsumeikan University	Peculiar Index Relations, 2D TQFT, and Universality of SUSY Enhancement
We study a class of 4D N=2 superconformal field theories obtained by exactly marginal gaugings involving Argyres-Douglas (AD) theories, and show that these theories are closely related to certain Lagrangian theories of class S. From this relation, we read off the precise action of S-duality on the flavor symmetry, and also find expressions for the Schur indices of two infinite series of exotic AD theories. We then show that, when reduced to 3D, these exotic AD theories can generically flow to interacting theories with 32 supercharges.
Poster Session 2 (16:00-18:30)
Reona Arai	Tokyo Institute of Technology	Superconformal index and supersymmetry enhancement of S-fold theories
Recently concrete models of 4d $\mathcal{N}=3$ superconformal field theories called S-fold theories are constructed by Garcia-Etxebarria and Regalado. Although it is difficult to study these theories due to the lack of the Lagrangian description and the strong coupling, it is expected that there is a non-trivial supersymmetry enhancement for rank one and two theories by Aharony and Tachikawa. In this poster, we evaluate the first non-trivial finite rank corrections to the superconformal index of these theories by using AdS/CFT correspondence and check the supersymmetry enhancement. To evaluate the index in finite rank, we mainly focus on the D3-branes wrapping a non-trivial three cycle on AdS side interpreted as Pfaffian-like operators on CFT side. We see that our results agree with the results expected from the supersymmetry enhancement.
Kohta Hatakeyama	Shizuoka University	Space-time structure and the Dirac zero modes from classical solutions in the Lorentzian type IIB matrix model
The type IIB matrix model is a conjectured non-perturbative formulation of superstring theory, and as such it is expected to explain the origin of space-time and matter at the same time. This has been partly demonstrated by the previous Monte Carlo studies on the Lorentzian version of the model, which suggested the emergence of (3+1)-dimensional expanding universe. Here, we investigate the same model by solving numerically the classical equation of motion, which is expected to be valid at late times since the action becomes large due to the expansion of space. Many solutions are obtained by the gradient decent method starting from random matrix configurations assuming a quasi-direct-product structure for the (3+1) dimensions and the six extra dimensions. We find that these solutions generally represent expanding space-time with smooth structure. Assuming further some block diagonal structure in the extra dimensions, we observe emergence of zero modes of the Dirac operator in (3+1) dimensions as the matrix size is increased.
Tomonori Inoue	Kobe University	5d Dirac fermion on quantum graph
The Standard Model still contains several problems. We introduce extra dimensions and try to solve the three problems, the generation problem, the fermion mass hierarchy problem and the origin of the CP violating phase in the Cabbibo–Kobayashi–Maskawa matrix. We investigate a 5d Dirac action on a quantum graph, which consists of bonds and vertices. We take a rose graph, as a quantum graph, which consists of one vertex and $N$ bonds, where each bond forms a loop that begins and ends at the vertex. The reason why we consider the rose graph is that it possesses most general geometry with $N$ bonds in a single extra dimension. In this talk we show that allowed boundary conditions (BCs) on the rose graph can be classified into $(2N+1)$ distinct types of BCs and clarify how many massless chiral fermions appear in the 4d mass spectrum for each type of BCs. The number of massless chiral fermions is shown to be a topological one and to be related to a Witten index. This model possesses the desired properties to solve the above problems.
Shoichi Kawamoto	Chung Yuan Christian University	Exploring multipartite steering effect using Bell operators
Einstein-Podolsky-Rosen (EPR) steering represents quantum correlation intermediate between entanglement and Bell nonlocality. We evaluate the steering ability of the superposition of two non-commuting Bell operators and explore the strong connection between the EPR steering and joint measurability based on the nonlinear steering inequalities. The necessary and sufficient criteria of unsteerability are investigated and demonstrated in the qutrit case.
Tomomi Kitade	Nara Women's University	Sine-square-deformation as gauge-fixing
Open string field theories expanded around identity-based tachyon vacuum solutions possess a gauge symmetry of closed string theories. This mechanism is realized by sine-square-deformation which has been developed in condensed matter physics. We show that sine-square-deformation can be understood as gauge-fixing.
Kazuki Kiyoshige	Osaka City University	Selection Rules for Schur Multiplets in 4D N=2 Superconformal Field Theories
In this study, we calculated the three-point correlation functions of the three Schur operators in 4d $\mathcal{N} = 2$ SCFT, and determined the operator product expansion (OPE). This is a general result of 4d $\mathcal{N} = 2$ SCFT because it is performed using only the symmetry of 4d $\mathcal{N} = 2$ superconformal algebra. Our computation leads to more general OPE selection rules which the currently known. By performing this calculation, it is expected that the relationship between 4d SCFT / 2d Chiral algebras can be understood more deeply.
Issei Koga	Kyushu University	Catalysis of higher dimensional static black hole in metastable vacuum decay
Recent studies suggest that our universe exists in the metastable vacuum and may decay. Previous study showed a black hole induces the catalysis for the decay of the metastable vacuum. We want to reveal the catalysis in the superstring theory. As the first step, this work extends the number of dimensions and shows the catalysis of static black holes in 5~10 dimensions.
Pompey Leung	Waseda University	Metric Deformations and Zero-Mode Wavefunctions on Blow-Ups of $\mathbb{C}^n/\mathbb{Z}_n$ Orbifolds
We explicitly analyse $O(\alpha')$ corrections to heterotic supergravity on resolutions of toroidal orbifold singularities. Using a conformal factor ansatz that is valid only for four dimensional geometries, we numerically investigate the behaviour around orbifold fixed points by considering the metric correction on the resolution of a $\mathbb{C}^2/\mathbb{Z}_2$ singularity. In contrast to the orbifold limit where the non-standard embedding scenario requires the inclusion of five-branes, a non-trivial conformal factor can be obtained on the resolution even without the presence of five-branes. In the same manner, we generalise our analysis to study metric corrections on $T^6/\mathbb{Z}_3$ and its resolution described by a complex line bundle over $\mathbb{CP}^2$. As a first step towards studying the effect of such $O(\alpha')$ corrections on phenomenology, we also studied the wavefunctions of internal zero-modes on the uncorrected $\mathbb{C}^n/\mathbb{Z}_n$ resolution. Such zero-mode wavefunctions are important in the generating of four dimensional effective Yukawa couplings in a realistic or semi-realistic Standard Model. Further prospects of including $O(\alpha')$ corrected metrics in the analysis of internal zero-modes as a novel approach in obtaining Yukawa couplings are discussed.
Myungbo Shim	Kyung Hee University	Analysis of Wrapped branes in 6-dimensional Romans gauged supergravity.
We explore the spectrum of lower-dimensional anti-de Sitter solutions in $F(4)$ gauged supergravity in six dimensions. The ansatz employed corresponds to D4-branes partially wrapped on various supersymmetric cycles in special holonomy manifolds. Re- visiting and extending the previouis results by M. Naka, in this article we consider the cases of two, three, and four-dimensional supersymmetric cycles within Calabi-Yau threefold, fourfold, $G_2$ and $Spin(7)$ holonomy manifolds. We also report on non- supersymmetric vacua, and check their stability using the Breitenlohner-Freedman bound.
Haruya Suzuki	Ibaraki University	Cubic interaction vertices of bosonic higher spin fields in BRST-BV formalism
Higher spin (HS) gauge theory may be regarded as a　 generalization of the electromagnetic theory of a spin-1 photon and the linearized gravity of a spin-2 graviton. String theory which has infinitely many massive modes may be seen as the broken phase of the HS gauge symmetry. Recently Vasiliev’s HS theory, which is composed of infinitely many symmetric tensors in AdS4 space, has shed new light on the AdS/CFT duality. To gain more insight into the duality, quantization of the theory must be achieved, however the action for it is not known yet. In this presentation, we consider cubic interaction vertices of bosonic HS fields with spin s1, s2 and s3, in flat and AdS spaces. These vertices are classified as non-trivial elements of the BRST-BV cohomology.
Mitsuyo Suzuki	Osaka City University	On perturbation theory of supersymmetric gradient flow in N = 1 SQCD
In this poster, 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. A d+1-dimensional theory which reproduces the same perturbation series is presented.
Keito Takeuchi	Kobe University	Kaluza-Klein graviton from primordial non-Gaussianities
Primordial non-Gaussianities can be thought of as a high energy particle collider at the inflation scale, which is typically as high as $10^{14}$GeV. In this presentation, we explore how to probe KK graviton through the inflaton effective interaction and the primordial non-Gaussianities.
Toshiaki Takeuchi	Kobe University	Conformal three-point functions in momentum space
We construct three-point functions with spinning operators in momentum space by explicitly solving the conformal Ward-Takahashi identities. In particular we demonstrate that they can be obtained by acting some differential operators on scalar three-point functions. We expect that our results are useful, e.g., for the Polyakov type bootstrap approach and study of cosmological correlation functions. This work is in collaboration with Hiroshi Isono and Toshifumi Noumi.
Pedro Hugo Tanaka	Kobe University	Dynamical generation of quark and lepton family structure in an extra dimension
We will talk about our recent work (arXiv:1905.11597) showing that the observed quark/lepton mass hierarchy can be realized dynamically on an interval extra dimension with point interactions, which are point-like deficits in the bulk space and provide us extra boundary conditions for five-dimensional fields. We determined the parameter configuration which describes the value of quark/lepton mass hierarchy by the minimization of the potential of our model. We explain how the minimization of the potential determines the positions of the point interactions, which are ones of the parameters to decide the value of quark/lepton masses. An additional gauge-singlet scalar (in our scenario) is shown to be important, whose vacuum expectation value possesses extra-dimensional coordinate-dependence, and it contributes to the quark/lepton mass hierarchy crucially.
Taizan Watari	Kavli IPMU	Modular forms for arithmetic elliptic curves with complex multiplication seen in string theory perspectives
It is said, in the field of arithmetic geometry, that a modular form is assigned to a certain class of elliptic curves defined over an algebraic number field. It is natural to wonder if such modular forms have something to do with modular forms that we can define on genus-one world-sheet in string theory, and if so, how. We focus on "elliptic curves of Shimura type", and clarify the relation between the "modular parametrization" in arithmetic geometry and "g=1 chiral correlation functions" in string theory. This presentation is based on a joint work with Satoshi Kondo.
Shota Yanai	Tokyo University of Science	Compact boson stars and charged black holes in the $CP^{2n+1}$ model
Q-balls are nontopological solitons which appear in certain nonlinear complex scalar field models. When they couple with gravity, boson stars arise. We study compact Q-balls(-shells) and compact boson stars(shells) in nonlinear sigma model with $CP^{2n+1}$ target space. We find the new $U(1)$ gauged Q- balls(-shells) and their gravitating solutions. We will show our new solutions and discuss basic properties of our solutions of charged black holes.
Katsuya Yano	Osaka City University	Progress in the matrix model formulation of N = 2 SUSY gauge theories & Painleve
We study the $\mathcal{N}=2$ $SU(2)$ supersymmetric gauge theories by using the matrix model. In our previous work, we have computed the partition function of the unitary matrix model which corresponds to the prepotential of the $N_f = 2$ theory. In the double scaling limit, we have found that the partition function of the matrix model obeys the Painleve II equation. We study the generalization of our previous work by considering the more general potential and take the double scaling limit for this model.
Mian Zhu	The Hong Kong University of Science and Technology	Constructing a Toy Alternative to Inflation Model Using Horava-Lifshitz Theory and Euclidean Quantum Gravity
We work out the scalar perturbation of an toy alternative to inflation model, proposed firstly by $arXiv:1709.07084$ using Horava-Lifshitz theory and Euclidean Quantum Gravity approach to solve the flatness problem. We recover the scale-invariant power spectrum with certain Lifshitz field. This result may motivate an alternative to inflation model for very early universe.
August 23 (Fri)
Morning Session 1 (9:00-10:10)
Seyed Morteza Hosseini	Kavli IPMU	Supersymmetric localization and black holes microstates^*
I will review recent progresses on deriving the entropy of AdS black holes using supersymmetric localization.
Morning Session 2 (10:30-11:45)
Hyojoong Kim	Kyung Hee University	Black holes with baryonic charge and I-extremization
Recently it was discovered that twisted superconformal index ${\mathcal{I}}$ can be used to understand the Bekenstein-Hawking entropy of magnetically charged black holes in AdS spacetime. We apply the so-called $\mathcal{I}$-extremization procedure to three-dimensional gauge field theories and their geometric dual, focusing in particular on the seven-dimensional Sasaki-Einstein manifold $M^{1,1,1}$. We generalize recent studies on relations among toric geometry, variational principles, and black hole entropy to the case of AdS$_2 \times Y_9$, where $Y_9$ is a fibration of toric Sasaki-Einstein manifold $M^{1,1,1}$ over a two- dimensional Riemann surface $\Sigma_g$. The nine-dimensional variational problem is given in terms of an entropy functional. In order to illustrate the computations as explicitly as possible, we consider cases where either only mesonic or baryonic fluxes are turned on. By employing the operator counting method, we calculate the $S^3$ free energy and the topologically twisted index $\mathcal{I}$ at large-$N$. The result for $\mathcal{I}$, it turns out, can be also obtained from the variational principle of the entropy functional with mesonic fluxes. We also study asymptotically AdS${}_4$ black holes which are magnetically charged with respect to the vector field in the Betti multiplet. By extremizing the entropy functional with baryonic flux, we compute the entropy and find that it agrees with the entropy of an explicit solution in a four-dimensional gauged supergravity which is a consistent truncation of eleven-dimensional supergravity in AdS${}_4\times M^{1,1,1}$.
Shota Fujiwara	Tokyo Institute of Technology	D3-brane analysis for the superconformal index in AdS$_5$/CFT$_4$
We study the AdS$_5$/CFT$_4$ correspondence for ﬁnite $N$ by using the superconformal index. Especially, we calculate the ﬁnite $N$ corrections to the superconformal index from the dual gravity theory. Our method is based on the assumption that D3-branes wrapped around three-cycles in the internal space reproduce the ﬁnite $N$ corrections. A recent work by Arai and Imamura showed that this method gives non-trivial predictions for S-fold theories. We further find this approach actually gives the known superconformal index (localization result) for leading corrections for orbifold quiver gauge theories.
Yiwen Pan	Sun Yat-sen University	Localizing Schur correlation functions
Schur operators in a 4d $\mathcal{N}$=2 theory form a chiral algebra under OPE, and they are counted by the Schur index which can be identified with the vacuum character of the associated chiral algebra. We derive such identification via localization on $S^3 \times S^1$. Further more, by generalizing the well-known localization argument, we show that all Schur operators, though being non-BPS, can be localized. The matrix integral computing the exact Schur correlation function is given. By introducing surface defects, characters of non-vacuum module can also be accessed via localization.
Morning Session 3 (12:00-13:40)
Naotaka Kubo	Yukawa Institute for Theoretical Physics	Hanany-Witten Transition in Quantum Curves
It was known that the $\mathrm{U}(N)^4$ super Chern-Simons matrix model describing the worldvolume theory of D3-branes with two NS5-branes and two $(1,k)$5-branes in IIB brane configuration (dual to M2-branes after taking the T-duality and the M-theory lift) corresponds to the quantum curve which has $D_5$ symmetry. We study the correspondence in detail and, by matching the two sides, we find a relation between the $D_5$ symmetry and the symmetries of branes such as Hanany-Witten transition. This provides a new viewpoint for brane symmetries.
Yuji Sugimoto	University of Science and Technology of China	Quantum Mirror Map for Del Pezzo Geometries
It was known that algebraic curves of genus one (called Del Pezzo geometries), which control M2-brane physics or five-dimensional gauge theories, are classified by the Weyl group of exceptional algebras. From this viewpoint, it is expected that the large Weyl group would be helpful for clarifying the structure of physical quantities. In this talk, we study the quantum mirror map of the D5 Del Pezzo geometry from the period integrals. We reproduce correctly the group-theoretical structure and the multi-covering structure with the following two interesting observations: (1) The representations appearing in the quantum mirror map are almost the same as those appear in the BPS indices. (2) Unlike the BPS indices, the decomposition into representations does not enjoy exact positivity, though the exceptions are only a few.
Hirotaka Hayashi	Tokai University	Wall-crossing and operator ordering for 't Hooft operators in N=2 gauge theories
We study half-BPS 't Hooft line operators in 4d N=2 $U(N)$ gauge theories on $S^1 \times \mathbb{R}^3$ with an $\Omega$-deformation. The recently proposed brane construction of 't Hooft operators shows that non- perturbative contributions to their correlator are identified with the Witten indices of quiver supersymmetric quantum mechanics. For the products of minimal 't Hooft operators, a chamber in the space of Fayet-Iliopoulos parameters in the quantum mechanics corresponds to an ordering of the operators inserted along a line. These considerations lead us to conjecture that the Witten indices can be read off from the Moyal products of the expectation values of the minimal 't Hooft operators, and also that wall-crossing occurs in the quantum mechanics only when the ordering of the operators changes. We provide evidence for the conjectures by explicitly computing the Witten indices for the products of two and three minimal 't Hooft operators in all possible chambers.
Naoki Yamatsu	Kyoto University	Is Symmetry Breaking into Special Subgroup Special?
Recently, I have proposed new-type grand unified theories (GUTs) ``Special GUTs.'' In this framework, the GUT gauge groups must be broken to their special subgroups. Many people seem to believe that symmetry groups are broken to regular subgroups, not to special subgroups. In this talk, I will show that the symmetry breaking into special subgroups is not special, by using dynamical symmetry breaking pattern in 4D SU(N) Nambu--Jona-Lasino type models. This talk is based on arXiv:1904.06857 with T. Kugo.

YITP WorkshopStrings and Fields 2019

Program

August 19 (Mon)

August 20 (Tue)

August 21 (Wed)

August 22 (Thu)

August 23 (Fri)

YITP Workshop
Strings and Fields 2019