2015年度セミナー (Seminar Schedule 2015)
Ramond-Ramond couplings of D-branes
| When: | 2015/04/15 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Sotaro Sugishita (Kyoto Univ.) |
| Abstract: | We find the Ramond-Ramond coupling formula including open string massive modes on D9-branes in the context of the boundary string field theory (BSFT). For superstring theory, the BSFT action of open string is given by a disk partiton function with boundary interactions corresponding to open string excitations. Applying the supersymmetric localization technique to superstring worldsheet theory with arbitrary worldsheet-supersymmetric boundary interactions of open superstring bosonic excitations, we find that a finite number of massive modes can contriute to Ramond-Ramond coupling formula and that the formula is written in terms of Quillen's superconnection including higher form fields. |
| Reference: | arXiv:1501.00995 |
Compactification on Riemann surfaces with a boundary and 2d CFT
| When: | 2015/04/22 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Koichi Nagasaki (KEK) |
| Abstract: | |
| Reference: |
6d N=(1,0) theories on T² and class S theories
| When: | 2015/05/13 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Kantaro Omori (Univ. of Tokyo, Hongo) |
| Abstract: | We have shown in the reference that the N=(1,0) superconformal theory on a single M5 brane on the ALE space of type G=An,Dn,En, when compactified on T2, becomes a class S theory of type G on a sphere with two full punctures and a simple puncture. In this talk, I will explain the basic properties of the N=(1,0) SCFT and how torus compactifications of those can be related to the class S theory of type G. I will also briefly touch the generalization to multiple M5 branes on the ALE space. |
| Reference: | arXiv:1503.06217 |
有限温度有限密度系における自発的対称性の破れと南部ゴールドストーンモード
| When: | 2015/05/22 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yoshimasa Hidaka (RIKEN) |
| Abstract: | 固体や空気(古典流体)中，超流動(量子流体)中の音波，強磁性体中のスピン波など自然界に現れる多くの古典的，量子的なギャップレスモードは対称性の破れに起因する．本講演では，ローレンツ不変な真空だけではなく，有限温度有限密度のような一般的な系で，対称性の破れとそれに伴いどの様なギャップレスモードが現れ，どのような分散関係を持っているか議論する． |
| Reference: | arXiv:1406.6271 |
On skein relations in class S theories
| When: | 2015/06/03 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Noriaki Watanabe (Kavli IPMU) |
| Abstract: | Recently, it is conjectured that half BPS loops in some 4D N=2 supersymmetric gauge theories arising out of the compactications of 6d (2,0) SCFTs by punctured Riemann surfaces are geometrically described by networks on the 2D compactified geometry. First, I briefly review some necessary backgrouds and recent developments about these subjects and then see the simplest SU(2) case to explain how 4D loop charges are encoded in 2D geometry and what the OPEs and ``skein relations" are. The extension to SU(3) is nontrivial but several arguments had already existed. I will then explain more nontrivial extention to the SU(N) maximal SYM cases based on a conjecture that there should be related to quantum groups. In particular, for SU(3) case, I will mention a simple map between 4D charges and 2D geometry and a computation example in T_3 without known Lagrangian descriptions. The latter part of talk is based on a joint work with Y.Tachikawa (Hongo, Tokyo Univ.), arXiv/1504.00121. |
| Reference: | arXiv:1504.00121 and references therein |
On the Jeffrey-Kirwan residue of $ \mathrm{BCD}$-instantons
| When: | 2015/06/10 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Satoshi Nakamura (Univ. of Tokyo, Hongo) |
| Abstract: | It is well known that instanton partition functions for $4$d $ \mathcal{N}=2$ SYM theories with classical gauge group can be expressed by finite dimensional integrals. In the last few years the Jeffrey-Kirwan(JK) residue operation was found to give their appropriate integration cycles, which enables us to compute such cumbersome multiple integrals. We examine how the JK-residue works for the case with symplectic or orthogonal gauge group and construct an algorithm to perform the multiple integral, which ends up with a sum over fixed points of the instanton moduli space. As a result, we find a simple formula for the "$ \mathrm{Sp}(0)$" pure SYM theory. |
| Reference: | arXiv:1502.04188 |
Accidental Kähler Moduli Inflation
| When: | 2015/06/17 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yoske Sumitomo (KEK) |
| Abstract: | I introduce a model of accidental inflation in type IIB string theory where inflation occurs near the inflection point of a small Kähler modulus. A racetrack structure helps to alleviate not only the known concern of string-loops, but also the hierarchy of gauge ranks required for the separation between moduli stabilization and inflationary dynamics. |
| Reference: | arXiv:1504.07202 |
5D SYM on 3D Deformed Spheres
| When: | 2015/07/08 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Teruhiko Kawano (Univ. of Tokyo, Hongo) |
| Abstract: | We reconsider the relation of superconformal indices of superconformal field theories of class S with five-dimensional N=2 supersymmetric Yang-Mills theory compactified on the product space of a round three-sphere and a Riemann surface. We formulate the five-dimensional theory in supersymmetric backgrounds preseving N=2 and N=1 supersymmetries and discuss a subtle point in the previous paper concerned with the partial twisting on the Riemann surface. We further compute the partition function by localization of the five-dimensional theory on a squashed three-sphere in N=2 and N=1 supersymmetric backgrounds and on an ellipsoid three-sphere in an N=1 supersymmetric background. |
| Reference: | arXiv:1505.06565 |
$A_\infty$ structure from the Berkovits formulation of open superstring field theory
| When: | 2015/07/22 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Tomoyuki Takezaki (Univ. of Tokyo, Komaba) |
| Abstract: | When we quantize open string field theory, the structure called $A_\infty$ plays a crucial role. However, the Berkovits formulation of open superstring field theory, which is one of the most successful formulations of superstring field theory, is based on the large Hilbert space of the superconformal ghost sector, and we have not been able to see the $A_\infty$ structure in this formulation. Recently, on the other hand, Erler, Konopka and Sachs succeeded in constructing an action with the $A_\infty$ structure by formulating open superstring field theory based on the small Hilbert space. In this talk, we show that the action with the $A_\infty$ structure can be obtained from an action based on the large Hilbert space by partial gauge fixing, and the action based on the large Hilbert space is related to the action of the Berkovits formulation by field redefinition. This talk is based on a paper with Erler and Okawa. |
| Reference: | arXiv:1505.01659 |
6d SCFTs and their compactifications
| When: | 2015/10/21 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Kazuya Yonekura (Kavli IPMU) |
| Abstract: | Recently, numerous superconformal field theories in six dimensions with N=(1,0) supersymmetry are found and classified. I will talk about a nice subclass of those theories which we call “theories Higgsable to N=(2,0)”, and discuss their compactifications on a circle and a torus, and their relations to class S theories. |
| Reference: | arXiv:1508.00915 |
cMERA as Surface/State Correspondence in AdS/CFT
| When: | 2015/10/28 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Noburo Shiba (YITP) |
| Abstract: | We present how the surface/state correspondence, conjectured in arXiv:1503.03542, works in the setup of AdS3/CFT2 by generalizing the formulation of cMERA. The boundary states in conformal field theories play a crucial role in our formulation and the bulk diffeomorphism is naturally taken into account. We give an identification of bulk local operators which reproduces correct scalar field solutions on AdS3 and bulk scalar propagators. We also calculate the information metric for a locally excited state and show that it is given by that of 2d hyperbolic manifold, which is argued to describe the time slice of AdS3. |
| Reference: | arXiv:1506.01353 |
2d Partition Function in $\Omega$-background and Vortex/Instanton Correspondence
| When: | 2015/11/06 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Toshiaki Fujimori (Keio univ.) |
| Abstract: | We derive the exact vortex partition function in 2d ${\cal N} = (2, 2)$ gauge theory on the $\Omega$-background, applying the localization scheme in the Higgs phase. We show that the partition function at a finite $\Omega$-deformation parameter $\epsilon$ satisfies a system of differential equations, which can be interpreted as a quantized version of the twisted F-term equations characterizing the SUSY vacua. Using the differential equations derived in this paper, we show the correspondence between the partition function of the two-dimensional vortex string worldsheet theory and the Nekrasov partition function at the root of Higgs branch of the four-dimensional ${\cal N} = 2$ theory with two $\Omega$-deformation parameters ($\epsilon_1$, $\epsilon_2$). |
| Reference: | arXiv:1509.08630 |
日ハンガリー2国間交流国内研究会
| When: | 2015/11/20 (Fri.) 12:30-18:00 |
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| Where: | Honkan (Main Bldg.) H1-55B |
| Speaker: | 小松 尚太$^a$ , 野坂 朋生$^b$ , 丸吉 一暢$^c$ ($^a$Perimeter Institute , $^b$京大基研 , $^c$Imperial College London) |
| Abstract: | 12:30 - 13:30 小松さん I “Integrability for Three-point Functions in N=4 SYM" 13:30 - 14:00 休憩 14:00 - 15:00 小松さん II “Integrability for Three-point Functions in N=4 SYM" 15:00 - 15:30 休憩 15:30 - 16:30 野坂さん "Instanton effects of M2-branes in various orbifolds” 16:30 - 17:00 休憩 17:00 - 18:00 丸吉さん “N=1 chiral theories of class S" |
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Weak Gravity Conjecture in AdS/CFT
| When: | 2015/11/25 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yu Nakayama (Kavli 数物連携宇宙研究機構 （東京大学）) |
| Abstract: | I'm going to disuss a possible implication of the weak gravity conjecture "Gravity is the weakest force" in the context of the AdS/CFT correspondence. This talk is based on the collaboration with Yasunori Nomura at UC Berkeley. |
| Reference: | arXiv:1509.01647 |
Neutrino masses and mixings as a signature of GUT, and the impact of nucleon decay and leptogenesis
| When: | 2015/12/04 (Fri.) 15:00-16:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Nobuhiro Maekawa (Nagoya Univ.) |
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Non-relativistic Strings and Non-geometric Backgrounds of Double Field Theory
| When: | 2015/12/09 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Charles Melby-Thompson (Fudan University) |
| Abstract: | Double field theory (DFT) provides a description of the massless degrees of freedom of (super-)string theory in which T-duality is made manifest by doubling the dimension of spacetime. Interestingly, DFT admits backgrounds that do not have a simple interpretation in terms of Riemannian geometry. We show that one such background corresponds to the non-relativistic string limit of Gomis-Ooguri, and by studying the fluctuations around this background we find that DFT naturally describes the gravitational excitations of the non-relativistic string. This work is in collaboration with S.M. Ko, J.-H. Park, and R. Meyer. |
| Reference: | arXiv:1508.01121 |
Supersymmetry Algebra in Super Yang-Mills Theories
| When: | 2015/12/18 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Shuichi Yokoyama (Keio univ.) |
| Abstract: | Supersymmetry algebra (superalgebra) is a basic object in supersymmetric theory. For example it contains information of exact mass spectrum of BPS objects determined by central charge, as shown by Witten-Olive in four dimensional case. Recently six dimensional superalgebra in supersymmetric Yang-Mills theories (SYM) has been computed. From six dimensional results superalgebras of five and four dimensional SYM has been derived by dimensional reduction. In five dimensional superalgebra the Kaluza-Klein momentum and the instanton particle charge are not the same but algebraically indistinguishable, which justifies the recent argument of identification of those charges in the relation of 5d MSYM and 6d (2,0) theory. In four dimensional superalgebra the extended supersymmetry algebras in four dimensional SYM including hypermultiplet's contribution leads to the famous formula of the central charge with the holomorphic coupling constant given in hep-th/9408099. |
| Reference: | arXiv:1506.03522 |
Exact Path Integral for 3D Quantum Gravity
| When: | 2016/01/20 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Akinori Tanaka (iTHES) |
| Abstract: | In 2007, it was conjectured by E.Witten that the chiral part of the partition function of 3d pure AdS Einstein gravity in quantum regime coincides with so-called modular J-function, a partition function of certain holomorphic CFT, called "monster CFT" considered by I. B Frenkel, J. Lepowsky and A. Meurman in the context of monstrous moonshine. We tried to calculate the partition function for the 3d pure AdS Einstein gravity directly by utilizing recently developed localization techniques.Based on some plausible assumptions, we arrived at CFT interpretations.For quantum gravity regime which corresponds to c=24, we get J-function.For semiclassical regime which corresponds c>>1, our partition function decomposes to Virasoro characters, and we derive Cardy formula. If possible, I will comment on application to quantum higher spin gravity. |
| Reference: | arXiv:1504.05991, arXiv:1510.02142, arXiv:1511.07546 |
Band spectrum is D-brane
| When: | 2016/01/27 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Taro Kimura (Keio Univ.) |
| Abstract: | We show that band spectrum of topological insulators can be identified as the shape of D-branes in string theory. The identification is based on a relation between the Berry connection associated with the band structure and the ADHM/Nahm construction of solitons whose geometric realization is available with D-branes. We also show that chiral and helical edge states are identified as D-branes representing a noncommutative monopole. In addition, we'd like to mention generalizations of our construction to other topological systems. |
| Reference: | arXiv:1509.04676 |
Interior of Black Holes and Information Recovery
| When: | 2016/02/10 (Wed.) 16:00-17:00 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yuki Yokokura (RIKEN) |
| Abstract: | We analyze time evolution of a spherically symmetric collapsing matter from a point of view that black holes evaporate by nature, and find that the collapsing matter evaporates without forming a horizon. Nevertheless, a Hawking-like radiation is created in the metric, and the object looks the same as a conventional black hole from the outside. We then discuss how the information of the matter is recovered. We also consider a black hole that is adiabatically grown in the heat bath and obtain the interior metric. We show that it is the self-consistent solution of the semi-classical Einstein equation, and that the four-dimensional Weyl anomaly induces the radiation and a strong angular pressure. |
| Reference: | arXiv:1509.08472 |
Exact results for ABJ Wilson loops and open-closed duality
| When: | 2016/03/25 (Fri.) 13:30-14:30 |
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| Where: | Honkan (Main Bldg.) H2-39 |
| Speaker: | Yasuyuki Hatsuda (Univ. of Geneve) |
| Abstract: | I will show that 1/2 BPS Wilson loops in ABJ theory are exactly related to the partition function in the same theory but with different ranks of gauge groups. This relation is understood as a kind of open-closed dualities. I would like to explain a few consequences of this relation. This talk is based on a collaboration work with Kazumi Okuyama. |
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