Haloes at the low-mass end in wino dark matter

2019年10月21日(月) 13:00 - 15:00

関口 豊和 (東京大学 ビッグバン宇宙国際センター (RESCEU))

Neutral wino is a natural candidate of dark matter in split-supersymmetry. Indirect detection is a promising probe of wino dark matter, with its annihilation enhanced non-perturvatively (i.e. Sommerfeld enhancement). In theoretical prediction, halo formation at the low-mass end is a key ingredient. For this purpose, we investigate kinetic decoupling of wino dark matter and consequent dark matter density perturbations. We show that inelastic processes involving charged wino, which are relevant for kinetic equilibrium at late times, shuts off abruptly. This results in boosted acoustic peaks in density power spectrum at horizon scales around the kinetic decoupling. Based on an analytic modeling of subhalo evolution, we estimate the subhalo mass function of (dwarf) galaxy-sized haloes and effects on the annihilation boost factor. We also discuss application of our analysis to SU(2)_L multiplet minimal dark matter.

会場: セミナー室 (160号室)

イベント公式言語: 英語

Introduction to 1QBit Open Software QEMIST "Quantum-Enabled Molecular ab Initio Simulation Toolkit"

2019年10月17日(木) 13:30 - 15:00

松浦 俊司 (Fundamental Researcher, Quantum Simulation Division, 1QBit, Canada)

会場: 研究本館 433号室

イベント公式言語: 英語

Dark matter search in extended dwarf spheroidal galaxies with CTA

2019年10月11日(金) 14:00 - 15:00

廣島 渚 (数理創造プログラム 特別研究員)

The nature of dark matter (DM) is still a big mystery. Among the varieties of candidates, Weakly Interacting Massive Particle (WIMP) is one of the most promising ones. Gamma-ray observations of dwarf spheroidal galaxies (dSphs) by Fermi satellites put the strongest constraints at mDM<~ a few hundreds of GeV. In the near future, Cherenkov Telescope Array (CTA) starts its operations and expect to probe WIMP of mDM>~O(1)TeV. Different from previous experiments, spatial distributions of DM in dSphs are resolved with CTA. In this talk, I explain how it affects our accessibility to DM annihilation cross-section.

会場: セミナー室 (132号室)

イベント公式言語: 英語

京大高等研究院-Heidelberg大学-理研 iTHEMS workshop “数理と医学”

2019年10月10日(木) 10:30 - 18:00

会場: SUURI-COOL (Kyoto)

イベント公式言語: 日本語

Finite N corrections to the superconformal index from D3-brane analysis in AdS_5/CFT_4

2019年10月8日(火) 15:30 - 17:00

荒井 玲於奈 (東京工業大学 博士課程)

In the context of the AdS/CFT, the Type IIB superstring theory on AdS_5 \times SE_5 corresponds to an N=1 quiver gauge theory, where SE_5 is a five-dimensional Sasaki-Einstein manifold. We study this correspondence by using the superconformal index, which contains the information of the BPS spectrum in the theory. It is known that the index of the large N limit is evaluated by the Kaluza-Klein modes on SE_5 and the agreement with CFT results was confirmed in many examples. In this talk, we consider the finite N corrections to the index on the gravity side as a next step. To do this, we focus on a single D3-brane wrapped around a three-cycle on SE_5. Because there are in general several three-cycles on SE_5, we need to sum up contributions of these single D3-branes. By using the D3-brane analysis, we propose a prescription to calculate the finite N corrections to the index. We explain our prescription through some examples and see the agreement with the CFT results calculated by the localization method.

会場: セミナー室 (160号室)

イベント公式言語: 英語

Workshop on Virtual Reality［Session 1］

2019年10月7日(月) 13:00 - 16:00

Gilles Ferrand and Don Warren will run a workshop on using virtual reality (VR) for data visualization and research. Anyone from any RIKEN campus, and any field of study, is welcome. We want to build a cross-disciplinary group of people with a shared interest in VR, and to apply this tool to a broad range of data types and topics. Please check the workshop website for up-to-date information !

会場: セミナー室 (132号室)

イベント公式言語: 英語

Topological phases of matter and operator algebras

2019年10月4日(金) 15:30 - 17:00

河東 泰之 (数理創造プログラム 客員主管研究員 / 東京大学 大学院数理科学研究科 教授)

Topological phases of matter are hot topics in recent physics and related to a wide range of mathematical fields. I will talk about their aspects related to operator algebras. Our emphasis will be on theory of tensor categories which describe interactions of anyons. This theory plays an important role in topological quantum computations. In theory of operator algebras, Jones initiated theory of subfactors and discovered the Jones polynomial, a new topological invariant for knots as an application. We apply this theory to mathematical studies of anyons.

会場: 大河内記念ホール

配信:計算科学研究棟 R511 / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

イベント公式言語: 英語

A new lamppost in dark matter searches: Composite Dark Matter

2019年10月1日(火) 10:00 - 18:00

リナルディ エンリコ (数理創造プログラム 研究パートタイマー Ⅰ)

In the search for the nature of dark matter many particle physics models are proposed. Models originating from a new strongly coupled dark sector, similar to QCD and Nuclear Physics, give rise to Composite Dark Matter particles. These models are hard to study, but they have a very interesting phenomenology with clear signals that are distinct from the usual WIMP candidates. To make robust predictions in Composite Dark Matter models one often needs to investigate non-perturbative effects due to the strong dynamics. In my talk I will explain how Lattice Field Theory methods and numerical simulations are well suited for this task and contribute to a solid uncertainty quantification. A variety of detection signals can be studied with lattice simulations, from dark matter self interactions to interactions with regular matter and even signals of dark phase transitions generating primordial gravitational waves.

会場: 研究本館 424-426号室

イベント公式言語: 英語

第2回MeVガンマ線天文学研究会

2019年9月26日(木) - 27日(金)

観測技術の進展により、電波からガンマ線、さらには宇宙線、重力波と様々な観測手段を我々は手に入れ、多波長・多粒子天文学が始まりつつあります。特にガンマ線帯域は、Fermi が GeV 領域において3000天体を報告し、2018年には CTA/LST 初号機が完成し、今後 >30 GeV 領域でも 1000天体程が発見されると期待されています。しかし、 MeV ガンマ線帯域は、観測の難しさから、1991年に打ち上げられた CGRO 衛星以降大きな進展がありません。 MeV ガンマ線は X 線以下の低エネルギー領域とガンマ線領域をつなぐ帯域であると同時に、核ガンマ線という新しい観測指標を我々にもたらす重要なエネルギー帯域でもあります。一方で、予算規模の大きな衛星計画の道のりは長いのも事実です。そこで、本研究会では、2020年代に計画されている MeV ガンマ線気球実験に焦点を当て、最新のMeV ガンマ線観測装置の現状・展望、MeV ガンマ線気球実験で可能となるサイエンスの洗い出しを兼ねた研究会を持つことになりました。 皆様の積極的なご参加をお待ちしております。 場所：東大・本郷キャンパス 理学部１号館 2F 279号教室 世話人：井上 (理研)、深沢 (広大)、渡辺 (ISAS)、中澤 (名大)、小高 (東大)、前田 (京大)、高田 (京大) 主催：東京大学、理化学研究所数理創造プログラム

会場: 東京大学 本郷キャンパス 理学部１号館 2F 279号教室

イベント公式言語: 日本語

Angular power spectrum analysis on current and future high-energy neutrino data

2019年9月18日(水) 14:00 - 15:00

Ariane Dekker (Faculty of Science, University of Amsterdam, Netherlands)

The astrophysical neutrino events that have been measured in the last couple of years show an isotropic distribution on the sky. To constrain the contribution of source populations to the observed neutrino sky, we consider isotropic and anisotropic components of the diffuse neutrino data. We simulate through-going muon neutrino events by applying statistical distributions for the fluxes of extra-galactic sources and investigate the sensitivities of current (IceCube) and future (IceCube-Gen2 and KM3NeT) experiments. I will show that the angular power spectrum is a powerful probe to assess the angular characteristics of neutrino data and demonstrate that we are already constraining rare and bright sources with current IceCube data. In addition, I will investigate the decay and annihilation of very heavy dark matter as a potential neutrino source suggested by the excess in HESE data. We apply our angular power spectrum analysis to HESE data for different channels, allowing us to interpret the observed neutrino sky and perform a sensitivity forecast.

会場: 研究本館 1階 160号室

イベント公式言語: 英語

iTHEMS Biology Seminar

2019年9月13日(金) 15:00 - 17:20

久保田 浩行 (九州大学 生体防御医学研究所 教授)
上江洲 安史 (NTTコミュニケーション科学基礎研究所 感覚運動研究グループ 研究員)

Timetable 15:00-16:00 Hiroyuki Kubota (Kyushu Univ.) 16:00-16:20 Break 16:20-17:20 Yasufumi Uezu (NTT) Time: 15:00-16:00 Speaker: Hiroyuki Kubota (Kyushu Univ.) Title: Regulation of insulin action by temporal patterns of insulin Abstract: Cells respond to various extracellular stimuli through a limited number of signaling pathways. One strategy to process such stimuli is to code the information into the temporal patterns of molecules. Almost all hormones exhibit distinct temporal patterns and the importance of their patterns has been reported. However, the mechanisms of how hormones regulate downstream molecules depending on their temporal patterns remain unknown. We focused on insulin which plays crucial roles on glucose homeostasis and shows several temporal patterns in vivo. In this study, we show how the Insulin signaling pathway processes the information encoded into the temporal patterns of blood insulin using a cultured cell line and mice. We found that insulin patterns selectively regulate the insulin-AKT pathway, metabolites, and mRNAs. Mathematical modeling revealed the mechanisms via differences in network structures and from sensitivity and time constants. Given that almost all hormones exhibit distinct temporal patterns, temporal coding may be a general principle of system homeostasis by hormones. Time: 16:20-17:20 Speaker: Yasufumi Uezu (NTT) Title: Source-filter interaction brings various representation in speech and singing voice Abstract: Speech plays a very important role in human communication. The source-filter interaction, a model that takes into account the actual speech production process, assumes that the sound source generation mechanism and the vocal-tract filter are not independent, but affect each other physiologically and acoustically. It is known that the source-filter interaction brings about non-linearity of speech and singing, such as singing voice with a loud volume and wide pitch range like an opera singer, or voice register transition where the vocal suppression and/or the voice pitch jump occurs. I would like to introduce my researches targeting non-linear vocalization phenomena due to the source-filter interaction and results of measuring and analyzing the time waveform of speech sound and vocal-fold vibrations through measurement experiments.

会場: 研究本館 424-426号室

イベント公式言語: 日本語

量子多体系入門－格子模型を中心に－

2019年9月5日(木) - 6日(金)

桂 法称 (東京大学 大学院理学系研究科 物理学専攻 准教授)

2019.09.05 @ 理研 研究本館 535-537号室 10:00-11:30 (1)イントロダクション -連続系から格子系へ- 13:00-14:30 (2)自由フェルミオン系と二次形式 15:00-16:30 (3)自由ボゾン系と二次形式 2019.09.06 @ 理研 研究本館 435-437号室 10:00-11:30 (4)古典・量子Ising模型 13:00-14:30 (5)量子スピン系の話題 15:00-16:30 (6)まとめと展望

会場: 研究本館 535-537号室 / 研究本館 435-437号室

イベント公式言語: 日本語

量子コンピュータの産業応用への展望

2019年9月4日(水) 15:30 - 18:00

中川 裕也 (株式会社 QunaSys)

会場: 大河内記念ホール

配信:計算科学研究棟 R311 / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

イベント公式言語: 日本語

Introduction to Quantum Annealing: from Fundamentals to Applications

2019年9月2日(月) - 3日(火)

入江 広隆 (数理創造プログラム 客員研究員 / 株式会社デンソー 先端技術研究所 アシスタントマネージャー)

Sep. 2 (Mon) 10:30-12:00, 13:30-15:00, 15:30-17:00 Lecture 1: What is quantum annealing and quantum computation? Lecture 2: Quatum Ising models as flux-qubit degree of freedom Lecture 3: Basic usage of quantum annealer Sep. 3 (Tue) 10:30-12:00, 13:30-15:00, 15:30-17:00 Lecture 4: Optimization problems and computational complexity Lecture 5: Real-world applications Lecture 6: Some other topics Room: 435-437 (main research building): Sep.2 (Mon) am 424-426 (main research building): Sep.2 (Mon) pm & Sep.3 (Tue) am+pm Abstract: Quantum annealing is a quantum-computational scheme which tackles computationally hard optimization problems. Its quantum-mechanically implemented machine, called quantum annealer, is commercially manufactured by D-Wave Systems, Inc., and is currently available with more than 2000 quantum bits. In this two-day lecture, I would like to discuss fundamental aspects of quantum annealing (1st day) and its real-world applications (2nd day). In particular, I try to overview the current status of the machine and several problems which we should theoretically overcome. In the first day, I will start with discussing what is quantum annealing and then review how quantum Ising model is implemented with flux-qubit degree of freedom. Later on, I will discuss the basic usage of the quantum annealer as a preparation for applications. In the second day, I will first summarize several classes of optimization problems and their computational complexity, and then discuss examples of real-world applications of quantum annealing. Finally, if I have enough time, I would like to discuss other related topic on quantum annealing.

会場: 研究本館 435-437号室 / 研究本館 424-426号室

イベント公式言語: 英語

「数理が紡ぐ新しい科学研究」連携ワークショップ 第一回 -生命医科学と数理科学-

2019年8月19日(月) - 20日(火)

数理科学はその普遍的・抽象的性格から、広い応用範囲を持ちます。数理を基盤として諸分野連携研究活動を行う4拠点が、数理と諸科学の連携研究の現状を共有し、数理により解決が望まれる科学研究の新しい姿を考える機会を設けることになりました。第一回は、生命医科学と数理科学をとりあげます。 主催 理化学研究所 数理創造プログラム (iTHEMS) 京都大学 理学研究科 サイエンス連携探索センター (SACRA) 東北大学 材料科学高等研究所 (AIMR) 北海道大学 電子科学研究所 社会創造数学研究センター (MSC)

会場: 北海道大学フロンティア応用科学研究棟 1Fセミナー室

イベント公式言語: 日本語

Physics of Gamma-Ray Bursts: Emission Mechanism, Particle Acceleration, Nucleosynthesis, and Gravitational Waves

2019年8月17日(土) 12:00 - 13:00

長瀧 重博 (数理創造プログラム 副プログラムディレクター / 理化学研究所 開拓研究本部 (CPR) 長瀧天体ビッグバン研究室 主任研究員)

Gamma-Ray Bursts (GRBs) are very powerful, special explosions of massive stars. In the explosions, highly relativistic jets are launched from progenitor stars and lots of gamma-rays are emitted from the jets. It is also suggested by gravitational wave detection with follow-up observations that (short duration) GRBs are triggered by neutron star mergers (NSMs). In this talk, physics of GRBs are introduced with some of our recent studies. I would like to introduce how the relativistic jets will emit bunch of gamma-rays, and how particle acceleration happens in the relativistic jets. I also would like to introduce our recent studies on r-process nucleosynthesis & gravitational wave emission at NSMs. Location: 50A-5132

会場: Lawrence Berkeley National Laboratory (Berkeley, California)

イベント公式言語: 英語

SUURI-COOL (Kyushu) Lecture

2019年7月31日(水) - 8月2日(金)

土井 琢身 (数理創造プログラム 専任研究員 / 理化学研究所 仁科加速器科学研究センター (RNC) 量子ハドロン物理学研究室 専任研究員)

SUURI-COOL (Kyushu) at the Ito-campus of Kyushu Univ. will be launched on July 31, 2019. As a first event at SUURI-COOL (Kyushu), the following lecture by Takumi Doi (RIKEN Nishina Center/iTHEMS) will be held. Feel free to join if you will be around Ito-campus. Nuclei, many-body systems of baryons as protons and neutrons, are ultimately consist of elementary particles of quarks and gluons and their properties are governed by quantum chromodynamics (QCD). Recently, a new theoretical method is developing in lattice QCD, the first-principles calculation of QCD, and the new era is dawning where nuclear physics is constructed directly based on QCD. In this lecture, I first introduce the formulation of lattice QCD. I will then discuss the theoretical foundation and the latest numerical results about the lattice QCD study of hadron interactions, the key quantities to construct nuclear physics from QCD. I will also give a lecture on computational science, in particular, about supercomputers.

会場: SUURI-COOL (Kyushu)

イベント公式言語: 英語

Complex analysis on a neighborhood of a complex submanifold and its applications

2019年7月30日(火) 16:00 - 18:10

小池 貴之 (大阪市立大学 大学院理学研究科 数学教室 講師)

Plan of the seminar: we separate each talk into two. In the first 60 minutes the speaker gives an introductory talk for non-mathematicians. After a short break, the second 60 minutes is spent for a bit more detailed talk for mathematicians (working in other areas). We welcome you joining both parts of the seminar or only the first/second half. Abstract: We explain our recent study on the complex analytic structure of a small tubular neighborhood of a complex submanifold, which is based on T. Ueda's classification theory. We also explain how to apply them to: (i) a study on (non-) existence of a smooth Hermitian metric on a nef line bundle over a projective manifold with semi-positive curvature, and (ii) a study on non-projective and non-Kummer K3 surfaces.

会場: セミナー室 (160号室)

イベント公式言語: 英語

京都大学数理解析研究所 共同研究(公開型) 「宇宙惑星ジェットの数理」

2019年7月29日(月) - 31日(水)

共催: 京都大学数理解析研究所 (RIMS)、理化学研究所数理創造プログラム (iTHEMS)

会場: 京都大学 総合研究 15 号館 (吉田キャンパス本部構内) 201号室

イベント公式言語: 日本語

Interstellar Memes

2019年7月25日(木) 20:00 - 21:30

ドン・ウォレン (数理創造プログラム 研究員)

Memes are to cultures what genes are to people: ideas, behaviors, or styles that are transmitted within the culture and can propagate or die out. The universe is a big place. How much of it knows about Grumpy Cat? Tale of Genji? Earth? Cost: JPY1,500 including a drink

会場: Good Heavens Bar (〒155-0032 東京都世田谷区代沢5-32-5)

イベント公式言語: 英語