次回のセミナー (Next Seminar)
Stokes phenomena and quantum integrability in non-critical string/M theory
| When: | 2012/06/08 (Fri.) 13:30-14:30 |
|---|---|
| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Hirotaka Irie (YITP) |
| Abstract: | We develop a general framework to study Stokes phenomena of the k x k isomonodromy systems with an arbitrary Poincare index r, especially which correspond to various kinds of non-critical string theory. Investigation of this system is important for the purpose of figuring out the non-critical version of M theory which unifies various solvable string theories in two-dimension, and Stokes phenomena of these systems have information of strong string-coupling physics which binds perturbative string-theory vacua together to formulate non-perturbatively complete string theory. In this talk, after a brief introduction to Stokes phenomenon in general ODE systems, we discuss how it plays a role in the framework of matrix models with explicit expressions of the Stokes multipliers in various cases. We also discuss an interesting connection between Stokes phenomena in matrix models and the discrete Hirota dynamics (T-systems) of quantum integrable systems, which would be an integrable structure of strong string-coupling dual side of non-critical string theory. |
| Reference: | arXiv:1109.2598, arXiv:1011.5745, arXiv:1003.1626, arXiv:0909.1197 |
最近のセミナー (Recent Seminars)
On supersymmetric interfaces in string theory
| When: | 2012/06/20 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yuji Satoh (Univ. of Tsukuba) |
| Abstract: | We construct the world-sheet interface which preserves space-time supersymmetry in type II superstring theories in the Green-Schwarz formalism. This is an analog of the conformal interface in two-dimensional conformal field theory. We show that a class of the supersymmetric interfaces generates T-dualities of type II theories, and that these interfaces have a geometrical interpretation in the doubled target space. We compute the partition function with a pair of the supersymmetric interfaces inserted, from which we read off the spectrum of the modes coupled to the interfaces and the Casimir energy between them. We also derive the transformation rules under which a set of D-branes is transformed to another by the interface. |
| Reference: | arXiv:1112.5935 [hep-th] (JHEP 1203 (2012) 072) |
Stokes phenomena and quantum integrability in non-critical string/M theory
| When: | 2012/06/08 (Fri.) 13:30-14:30 |
|---|---|
| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Hirotaka Irie (YITP) |
| Abstract: | We develop a general framework to study Stokes phenomena of the k x k isomonodromy systems with an arbitrary Poincare index r, especially which correspond to various kinds of non-critical string theory. Investigation of this system is important for the purpose of figuring out the non-critical version of M theory which unifies various solvable string theories in two-dimension, and Stokes phenomena of these systems have information of strong string-coupling physics which binds perturbative string-theory vacua together to formulate non-perturbatively complete string theory. In this talk, after a brief introduction to Stokes phenomenon in general ODE systems, we discuss how it plays a role in the framework of matrix models with explicit expressions of the Stokes multipliers in various cases. We also discuss an interesting connection between Stokes phenomena in matrix models and the discrete Hirota dynamics (T-systems) of quantum integrable systems, which would be an integrable structure of strong string-coupling dual side of non-critical string theory. |
| Reference: | arXiv:1109.2598, arXiv:1011.5745, arXiv:1003.1626, arXiv:0909.1197 |
Flux compactifications and static charged black holes in massive type IIA
| When: | 2012/05/16 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Tetsuji Kimura (Rikkyo Univ.) |
| Abstract: | We study static, spherically symmetric black hole solutions in four-dimensional N=2 gauged supergravity with one vector multiplet and one hyper-tensor multiplet. This is derived from massive type IIA theory compactified on the nearly-Kahler coset space G2/SU(3). It is well-known that the Romans' mass parameter yields the Stuckelberg-type deformation of the gauge field strengths in the four-dimensional system. This deformation requires that all the (covariant) derivatives of the scalar fields must vanish and the two-form field is closed. It turns out that charged solutions are forbidden. This implies that only AdS vacua or Schwarzschild-AdS black holes are allowed as the static, spherically symmetric solutions. Before the discussion of the main part, we will briefly exhibit several techniques on flux compactifications. |
| Reference: | arXiv:1203.1544 [hep-th], arXiv:1108.1113 [hep-th] |
Localization and Large N reduction on $S^3$ for the Planar and M-theory limit
| When: | 2012/05/09 (Wed.) 16:00-17:00 |
|---|---|
| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yutaka Yoshida (KEK) |
| Abstract: | We show a large N reduction on $S^3$ in a BPS sector for a broad class of theories : ${\cal N}\geq 2$ supersymmetric Chern-Simons theory with any number of adjoint and bi-fundamental chiral multiplet. We show that the localization method can be applied to the reduced model and the path integral can be written by multi-contour integral. By taking particular localization configuration, we also show that the large N equivalence between the original theory on $S^3$ and the reduced model holds for the free energy and for the expectation value of BPS Wilson loops. It turns out that the large N reduction on $S^3$ holds even for the M-theory limit. |
| Reference: | arXiv:1203.1016 |
Chiral Zeromodes on Vortex-type Intersecting Heterotic five-branes
| When: | 2012/04/27 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Masaya Yata (Sokendai(KEK)) |
| Abstract: | Type II string からbraneを用いて素粒子モデルを導く方法はよく知られているが、Heterotic string で同様なことをする方法はあまり知られていない。本研究では、E8×E8ヘテロティック理論においてドメインウォール（１次元）的なスメアされた交差5-ブレーン背景場における先行研究を一般化して、ボーテックス（２次元）的な背景場におけるゲージーノのディラック方程式を直接解き、ブレーン交差上に局在するカイラルゼロモードのスペクトラムを完全に求めた。その結果、無限タワーのフーリエモードのうち、ただ３つのみが正規化可能であり、その１つは他の２つと逆のカイラリティをもつことが示された。これは、２枚のE8×E8ヘテロティック5-ブレーンの交差に3つのE6の27表現に属するカイラル多重項が局在することを強く示唆するものとなる。 |
| Reference: | Chiral Zeromodes on Vortex-type Intersecting Heterotic five-branes M.Yata arXiv:1111.6015 Chiral Generations on Intersecting 5-branes in Heterotic String Theory T.Kimura, S.Mizoguchi arXiv:0912.1334 |
Numerical studies of the ABJM theory for arbitrary N at arbitrary coupling constant
| When: | 2012/04/20 (Fri.) 13:30-14:30 |
|---|---|
| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Masazumi Honda (Sokendai(KEK)) |
| Abstract: | We show that the ABJM theory, which is an N=6 superconformal U(N)*U(N) Chern-Simons gauge theory, can be studied for arbitrary N at arbitrary coupling constant by applying a simple Monte Carlo method to the matrix model that can be derived from the theory by using the localization technique. This opens up the possibility of robing the quantum aspects of M-theory and testing the AdS_4/CFT_3 duality at the quantum level. Here we calculate the free energy, and confirm the N^{3/2} scaling in the M-theory limit predicted from the gravity side. We also find that our results nicely interpolate the analytical formulae proposed previously in the M-theory and type IIA regimes. Furthermore, we show that some results obtained by the Fermi gas approach can be clearly understood from the constant map contribution obtained by the genus expansion. The method can be easily generalized to the calculations of BPS operators and to other theories that reduce to matrix models. |
| Reference: | arXiv:1202.5300 [hep-th] |
Towards q-deformations of the Mirror TBA
| When: | 2012/03/23 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | G. E. Arutyunov (Utrecht U.) |
| Abstract: | The mirror Thermodynamic Bethe Ansatz (TBA) is a tool to determine the spectrum of the AdS_5 x S^5 superstring. After an extensive introduction, I will discuss work in progress towards constructing a q-deformed version of the mirror TBA. |
| Reference: |
Gauge Fixing of Open Superstring Field Theory
| When: | 2012/02/22 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Shingo Torii (Univ. of Tokyo, Komaba) |
| Abstract: | We consider gauge fixing of the Wess-Zumino-Witten-type open superstring field theory. Analyzing the free theory, we find that there appear infinitely many ghost string fields and antighost string fields carrying various world-sheet ghost numbers and picture numbers. We propose a variety of gauge-fixing conditions, one of which manifests the relation to Witten's original superstring field theory, and calculate the corresponding propagators. We also determine the field-antifield content and the free master action in the Batalin-Vilkovisky formalism. Unlike in the bosonic string field theory, the master action does not take the same form as the original gauge-invariant action. |
| Reference: | arXiv:1201.1761, arXiv:1201.1762 |
Holographic three point functions for GKP strings from integrability
| When: | 2012/02/01 (Wed.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Shota Komatsu (Univ. of Tokyo, Komaba) |
| Abstract: | I will describe a holographic computation of a three point function of twist 2 operators with large spin in N=4 super Yang-Mills at strong coupling. In AdS/CFT correspondence, three point functions of non-BPS operators in the gauge theory correspond to three point functions of a worldsheet sigma model of string theory on AdS. When the gauge theory is strongly coupled and operators have large quantum numbers, the worldsheet sigma model becomes classical. In this limit, there are two different contributions to the three point functions: One is from the action of the sigma model and the other is from vertex operators. I will show that the contribution from the action can be computed by adapting integrability-based techniques invented previously for the gluon scattering problem. If time permits, I would also like to sketch how to calculate the contribution from vertex operators and show, if possible, a tentative result. |
| Reference: | arXiv:1110.3949 |
Line operators on $S^1 \times \mathbb{R}^3$ and AGT correspondence
| When: | 2012/01/25 (Wed.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H284A |
| Speaker: | Yuto Ito (Univ. of Tokyo, Komaba) |
| Abstract: | We perform an exact localization calculation for the expectation values of Wilson-'t Hooft line operators in $\mathcal{N} = 2$ supersymmetric gauge theories on $S^1 \times \mathbb{R}^3$. We twist the periodic boundary condition around $S^1$ and check the correspondence between the 't Hooft line operators with the twisted boundary condition and the Verlinde loop operators in Liouville field theory with a general value of the parameter appearing in the action. We also observe that the values of the line operators on $S^1 \times \mathbb{R}^3$ coincide with holonomies of flat connections on Riemann surfaces whose space is quantized Hitchin moduli space. |
| Reference: | arXiv:1111.4221 |
A Note on Kahler Potential of Charged Matter in F-theory
| When: | 2012/01/18 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Teruhiko Kawano (Univ. of Tokyo, Hongo) |
| Abstract: | We study the Kahler potential of charged matter fields, whose profiles have a peak on their matter curve --- on an "intersection" of 7-branes, in an F-theory compactification. It is shown that the Kahler potential is exactly given by the integral over the matter curve, but not by the integral over the whole GUT surface of 7-branes. |
| Reference: |
Atomic nucleus from string theory
| When: | 2012/01/11 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Koji Hashimoto (RIKEN) |
| Abstract: | In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass number (A) dependence r A1/3 for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multi-baryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1)×A1/3 [fm], which is consistent with experiments. |
| Reference: | arXiv:1103.5688 |
博士論文発表会
| When: | 2012/01/05 (Thu.) 13:30-18:00 |
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| Where: | Honkan (Main Bldg.) H284A |
| Speaker: | Takuya Saka, Koh Iwasaki (Tokyo Tech) |
| Abstract: | 13:30-15:30 Takuya Saka, "Instanton Caluculus in $\Omega$-deformed $\mathcal{N}=4$ Super Yang-Mills Theory." 16:00-18:00 Koh Iwasaki, "BPS States in World-volume Theories of M-branes and D-branes." |
| Reference: |
Chern-Simons Theories with a Vector Fermion
| When: | 2011/12/21 (Wed.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H284A |
| Speaker: | Shuichi Yokoyama (TIFR) |
| Abstract: | We investigate Chern-Simons theories coupling to vector matter. These kinds of model are quite interesting in the following sense. First, they provide us with infinitely many interacting conformal field theories (CFT) with Lagrangian description, which enables us to study CFT in a direct calculation. Second, these kinds of model are likely to be dual to higher spin theories in AdS4, which would have potential or possibility to reveal rich structure in high energy physics. After belief introduction of these backgrounds, I will talk about U(N) Chern-Simons theories coupling to a vector-like (fundamental/anti-fundamental) fermion. It turns out that this model can be handled exactly in 't Hooft limit. I will explain how to deal with it by means of large N technique. |
| Reference: | arXiv:1110.4386 |
Selberg Integral and SU(N) AGT Conjecture
| When: | 2011/12/14 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Hong Zhang (Univ. of Tokyo, Hongo) |
| Abstract: | An intriguing coincidence between the partition function of super Yang-Mills theory and correlation functions of 2d Toda system has been heavily studied recently. While the partition function of gauge theory was explored by Nekrasov, the correlation functions of Toda equation has not been completely understood. In this paper, we study the latter in the form of Dotsenko-Fateev integral and reduce it in the form of Selberg integral of several Jack polynomials. We conjecture a formula for such Selberg average which satisfies some consistency conditions and show that it reproduces the SU(N) version of AGT conjecture. |
| Reference: | arXiv:1110.5255, arXiv:1012.3137 |
Worldsheet formulation for the refined topological string theory
| When: | 2011/11/16 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yu Nakayama (Caltech/IPMU) |
| Abstract: | Nekrasov's partition function is defined on a flat bundle of R^4 over S^1 called the Omega background. When the fibration is self-dual, the partition function is known to be equal to the topological string partition function, which computes scattering amplitudes of self-dual gravitons and graviphotons in type II superstring compactified on a Calabi-Yau manifold. We propose a generalization of this correspondence when the fibration is not necessarily self-dual. |
| Reference: | arXiv:1106.5503 |
On S-duality of 5d super Yang-Mills on $S^1$
| When: | 2011/11/09 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yuji Tachikawa (IPMU) |
| Abstract: | After reviewing the basics of the S-duality of 4d N=4 super Yang-Mills with general gauge groups, its extension to 5d maximally supersymmetric Yang-Mills on $S^1$ will be discussed. It will be shown to be closely related to the reversal of arrows of Dynkin diagrams of affine Lie algebras. If we have time, the most subtle case involving the SU(odd) gauge theory with $Z_2$ twist and the USp theory with nontrivial 5d theta angle will also be discussed. |
| Reference: | arXiv:1110.0531 |
3d/3d 関係について
| When: | 2011/11/04 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yuji Terashima (Tokyo Tech) |
| Abstract: | 3d/3d 関係は3次元のゲージ理論と3次元の Chern-Simons 理論の等価性を主張する．この講演では，この主張の量的な証拠として，3次元のゲージ理論の分配関数から3次元双曲多様体の体積をどのように導けるか，について述べる． |
| Reference: | arXiv:1103.5748, arXiv:1106.3066 |
Solutions from boundary condition changing operators in open superstring field theory
| When: | 2011/10/26 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Toshifumi Noumi (Univ. of Tokyo, Komaba) |
| Abstract: | Since Schnable's construction of an analytic solution for tachyon condensation, a lot of classical solutions in open string field theory have been analytically constructed. In this talk, I will introduce an approach using boundary condition changing (bcc) operators. After reviewing previous solutions in the bosonic string using bcc operators, I will discuss their relation to boundary conformal field theories by considering the gauge-invariant observables corresponding to closed string one-point functions on the disk. And then, I will talk about our construction of solutions in the superstring. |
| Reference: | arXiv:1108.5317 |
${\cal W}_{1+\infty}$ algebra as a symmetry behind AGT relation
| When: | 2011/10/19 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Shotaro Shiba (KEK) |
| Abstract: | AGT(-W) relation claims that the partition functions of 4-dim ${\cal N}=2$ supersymmetric quiver gauge theories correspond to the correlation functions of Liouville (Toda) field theory times so-called "$U(1)$ factor". We take notice of this factor, and then find some evidences which imply that ${\cal W}_{1+\infty}$ algebra describes the symmetry behind AGT(-W) relation. In this seminar, I want to start from the concrete form of AGT(-W) relation, and to explain clearly why this $U(1)$ factor is related to ${\cal W}_{1+\infty}$ algebra. |
| Reference: | arXiv:1105.1667 |
Classical integrability of Schrodinger sigma models and q-deformed Poincare symmetry
| When: | 2011/10/12 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Io Kawaguchi (Kyoto U.) |
| Abstract: | 近年、AdS/CFT対応を拡張して、非相対論的共形場理論に適用しようという試みがなされてきた。Schrodinger時空はその際に現れる背景時空の一つである。ここでは、3次元Schrodinger時空を考え、その上の非線形シグマ模型の古典的な可積分構造について議論する。この模型の運動方程式は2通りのLax対を用いて記述できることを示した。それぞれの記述の背後にある対称性を同定し、古典r行列も求めた。両者は異なる対称性に基づく記述であるが、互いに等価で、非局所写像により関係している。また、この可積分構造は、3次元warped AdS空間上の非線形シグマ模型の持つ可積分構造と関係しており、両者の関係についても議論する。 |
| Reference: | arXiv:1109.0872 |