その他

Mathematical Application Research Team Meeting #13

2026年3月6日(金) 14:00 - 15:00

地引 知栄 (東京科学大学 理学院 数学科 博士課程)

The Mathematical Application Research Team is pleased to welcome Chiyaha Jibiki, who will join the team as an SPDR in April. He will give a talk at this meeting prior to his official start date. Everyone is welcome to join the meeting. Title: Left-Orders and Dynamics: Applications to Hyperbolic Geometry and Low-Dimensional Topology Abstract: A left-order on a group is a total order that is invariant under left-multiplication. The concept dates back to the early 20th century, when Dedekind and Hölder characterized the natural order on the real line purely in terms of group actions. In the 21st century, this theory has evolved significantly through connections with discrete dynamical systems. Currently, there is active research linking geometric structures to left-orders on geometrically significant groups, such as fundamental groups and mapping class groups. In this talk, I will introduce the framework of left-order theory, starting from the simple perspective of binary operations on infinite sets. I will then provide an overview of the field by presenting, as much as possible, the diverse applications arising from its high versatility. In particular, I will discuss the speaker's recent results concerning the structure of the space of left-orders (comparisons between left-orders) and methods for constructing specific left-orders. This talk includes joint work with Shuhei Maruyama (Kanazawa University).

会場: 研究本館 3階 359号室 (メイン会場) / via Zoom

イベント公式言語: 英語

Mathematical Application Research Team Meeting #12

2026年2月6日(金) 14:00 - 15:30

リッカルド・ムオロ (理化学研究所 数理創造研究センター (iTHEMS) 数理基礎部門 基礎科学特別研究員)

Mathematical Application Research Team invites Riccardo Muolo fom Division of Fundamental Mathematical Science to this meeting. You are welcome to join the meeting. Title: Dynamics beyond nodes: a topological framework for oscillatory dynamics on higher-order networks Abstract: In recent years, increasing attention has been given to dynamical processes taking place on higher-order networks, where interactions are not limited to links, but may involve also higher-dimensional simplices [1]. While classical network models assume that state variables live on nodes and interact through links, many real systems — including brain, climate, and transportation systems — cannot be fully described within this node-centric perspective [2]. In this seminar, I will introduce the framework of higher-order networks and the concept of topological signals, namely, dynamical variables defined on simplices of higher dimensions. I will briefly present the basic tools required for this setting, including elementary notions of discrete calculus, discrete topology and geometric algebra, which serve as the mathematical foundation for modeling dynamical processes beyond the node-based paradigm. Next, I will discuss models of oscillatory dynamics extended to this framework. First, I will present the topological Kuramoto model [3], in which phases are not restricted to nodes but may also be associated with links, and where the coupling arises from the combinatorial structure of the simplicial complex. Then, I will introduce the discrete Hodge Laplacian and the Dirac-Bianconi operator [4], the former generalizing diffusive interactions to the higher-order setting, while the latter provides cross-talk between signals defined on simplices of different dimensions. Finally, I will introduce the notion of Dirac-Bianconi driven oscillators, where the dynamics of node- and link-signals coexist, interact and may give rise to collective oscillatory behaviors [5].

会場: 研究本館 3階 359号室 (メイン会場) / via Zoom

イベント公式言語: 英語

Visit by ASCENT-6E high school students (2026)

2026年1月12日(月) 10:40 - 16:00

PROGRAMME Visit of students enrolled in the ASCENT Program at Chiba University Schedule 10:30-10:40 (10 min): Arriving procedure 10:40-11:00 (20 min) at the meeting room on the 4th floor, Main Research Building Introduction of students (to hear their names and scientific fields of interest). We will provide colour-coded badges for them to write their names, with each colour representing their field of interest (e.g., blue for biology, green for math, red for physics). 11:00-11:10 (10 min) Bathroom break 11:10-12:00 (50 min) at the meeting room on the 4th floor, Main Research Building First set of talks by iTHEMS members (10 min each) Catherine Beauchemin (Physics, biology) Gen Kurosawa (Biology) Yuta Sekino (Physics) Isaac Planas-Sitja (Biology) Wei-Hsiang Shao (Physics) 12:00-13:30 (90 min) at Common Space on the 4th floor of Main Research Building Discussion Lunch with students 13:30-14:20 (50 min) at the meeting room on the 4th floor, Main Research Building Second set of talks by iTHEMS members (10 min each) Ryo Namba (Physics) Sungsik Kong (Biology) Kenji Okubo (Biology) Steffen Backes (Physics) Jose Gutierrez (Biology) 14:20-14:30 (10 min) at the meeting room on the 4th floor, Main Research Building Brief overview of iTHEMS and RIKEN programmes (C.Beauchemin) (e.g., JRA, IPA, SPDR, RS/SRS) 14:30-14:40 (10 min) Bathroom break 14:40-14:55 (15 min) at the meeting room on the 4th floor, Main Research Building Short statements by Prof. Jun Nomura, Prof. Koji Tsuji, Prof. Kohei Watanabe, Prof. Yukiharu Akimoto, ASCENT program coordinators Qian Wang and Hina Morishige, graduate student Rin Chinen. 14:55-16:00 (65 min) at Common Space on the 4th floor of Main Research Building Informal discussions among ASCENT program students and iTHEMS members over some snacks and coffee. iTHEMS members will spread out across different areas in the common space on the 3rd floor and display posters or conduct activities to facilitate discussion.

会場: 研究本館 435-437号室

イベント公式言語: 英語

Mathematical Application Research Team Meeting #11

2025年12月12日(金) 15:00 - 16:30

松浦 壮 (慶応義塾大学 日吉物理学教室 教授)

Mathematical Application Research Team invites Prof. So Matsuura from Keio University for this meeting. You are welcome to join the meeting. Title: Phases and Duality in Fundamental Kazakov-Migdal Model on the Graph Abstract: In this talk, we will explore the fundamental Kazakov-Migdal (FKM) model on a generic graph, where the partition function is represented by the Ihara zeta function weighted by unitary matrices. The effective action of the FKM model is described by a summation of all Wilson loops on the graph, which can be regarded as an extension of the usual Wilson action in lattice gauge theory. We show that the FKM model on regular graphs exhibits an exact strong/weak coupling duality, reflecting the functional equation of the Ihara zeta function. We also discuss the relation between the stability of the FKM model and the pole distribution of the Ihara zeta function. Interestingly, the FKM model universally exhibits the so-called Gross-Witten-Wadia (GWW) phase transitions. We estimate the phase structure of the FKM model in both small and large coupling regions, which is validated through numerical simulations. If time permits, we will examine the phase transition of the FKM model from the Young diagram perspective and discuss its relation with the GWW phase transition indicated by the eigenvalue distribution.

会場: セミナー室 (359号室) (メイン会場) / via Zoom

イベント公式言語: 英語

京都大学MACSプログラムスタディグループ 理研訪問・研究交流会 —理研研究者と語る最前線—

2025年12月12日(金) 12:30 - 15:10

12:00 – 13:30 コーヒーミーティング参加 13:30 – 14:10 入谷 亮介 (理研 iTHEMS 上級研究員) — 研究キーワード:数理生物学, 進化生態学 14:10 – 14:30 休憩 14:30 – 15:10 森川 億人 (理研 iTHEMS 基礎科学特別研究員) — 研究キーワード: 格子場の理論, 共形場理論, 場の量子論, 素粒子論

会場: 研究本館 3階 345-347室

イベント公式言語: 日本語

Mathematical Application Research Team Meeting #10

2025年11月14日(金) 16:00 - 17:00

緒方 芳子 (京都大学 数理解析研究所 (RIMS) 教授)

Mathematical Application Research Team invites Prof. Yoshiko Ogata from RIMS for this meeting. Her talk title will be announced later. You are welcome to join the meeting. The title and the abstract of her talk are: Title: Mixed state topological order: operator algebraic approach Abstract: We consider anyons in mixed states of two-dimensional quantum spin systems within the operator-algebraic framework of quantum statistical mechanics. To each state satisfying a mixed-state version of approximate Haag duality, we associate a braided C*-tensor category, which we interpret as describing the anyonic excitations of the state. We then investigate how these anyonic structures behave under interactions with the environment.

会場: セミナー室 (359号室) 3階 359号室 (メイン会場) / via Zoom

イベント公式言語: 英語

Mathematical Application Research Team Meeting #9

2025年10月10日(金) 13:30 - 14:30

アントワーヌ・ディエズ (理化学研究所 数理創造研究センター (iTHEMS) 数理展開部門 数学応用研究チーム 研究員)

In this meeting, Antoine Diez will give a talk entitled "Mean-field limits a la Tanaka and large deviations for particle systems with network interactions." Feel free to join if you are interested.

会場: 研究本館 3階 359号室 (メイン会場) / via Zoom

イベント公式言語: 英語

iTHEMS NOW & NEXT 2025

2025年7月24日(木) - 25日(金)

We will hold this fiscal year’s annual in-house gathering, “iTHEMS NOW & NEXT,” as follows. This event is a rare opportunity for all iTHEMS members, including visiting researchers, to gain a comprehensive overview of iTHEMS’s current activities and future directions. Program July 24th 9:30-9:45 Opening by Director Iso 9:45-10:10 Keynote lecture Sonia Mahmoudi 10:10-10:35 Keynote lecture Masazumi Honda 10:35 20-min break 10:55 Fundamental Quantum Science Program (FQSP) introduction Working Group introduction 5-min each 11:30 Lunch break 13:30 Teams introduction part 1 RIKEN-Berkeley Center RIKENｰBerkeley Center (Shigehiro Nagataki) Mathematical Application Research Team (Motoko Kotani / Tsukasa Tada) 13:50 11 SG Presentation 5 min each 14:45 break 15:00 Flash talks & Poster session 18:00 Reception July 25th 9:30 Keynote lecture Yuto Yamamoto 9:55 Keynote lecture Kyosuke Adachi 10:20 break 10:40　Teams introduction part 2 Prediction Science Research Team (Takemasa Miyoshi) Medical Science Deep Learning Team (Jun Seita) Medical Science Data-driven Mathematics Team (Eiryo Kawakami) Quantum Mathematical Science Team (Tetsuo Hatsuda) Mathematical Social Science Team (Yohsuke Murase) 11:30 Lunch 13:30 Flash Talk & Poster presentation 16:30 Concluding remark

会場: 理化学研究所和光キャンパス 本部棟2階大会議室 (メイン会場) / via Zoom

イベント公式言語: 英語

DA-ML Study Group: Error Covariance

2025年7月23日(水) 9:00 - 10:00

トリスタン・ハスコエト (理化学研究所 計算科学研究センター (R-CCS) データ同化研究チーム 研究員)

会場: via Zoom / 計算科学研究棟 R511

イベント公式言語: 英語

6th Mathematical Application Research Team meeting

2025年7月4日(金) 11:00 - 12:00

阪田 直樹 (東北大学 材料科学高等研究所 (AIMR) 数学連携グループ 助教)

会場: via Zoom / セミナー室 (359号室) 3階 359号室

イベント公式言語: 英語

Visit by ASCENT-6E high school students

2025年1月13日(月) 10:40 - 16:00

PROGRAMME Visit of students enrolled in the ASCENT Program at Chiba University Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS): RIKEN Wako Campus (Wako City, Saitama) Event date: Monday, January 13th, 2025 ASCENT-6E Program: iTHEMS members: Schedule 10:30-10:40 (10 min): Arriving procedure 10:40-11:00 (20 min) at meeting room on the 4th floor, Main Research Building Introduction of students (to hear their names and scientific fields of interest). We will provide colour-coded badges to write their names and the colour would represent their field of interest (e.g., blue for biology, green for math, red for physics). 11:00-11:10 (10 min) Bathroom break 11:10-12:00 (50 min) at meeting room on the 4th floor, Main Research Building First set of talks by iTHEMS members (10 min each) Tetsuo Hatsuda (Physics, mathematics) Catherine Beauchemin (Physics, biology) Tsukasa Tada (Physics, mathematics) Gen Kurosawa (Biology) Misako Tatsuuma (Physics) 12:00-12:50 (50 min) at Common Space in the 4th floor of Main Research Building (tentative) Discussion Lunch with students 12:50-13:40 (50 min) at meeting room on the 4th floor, Main Research Building Second set of talks by iTHEMS members (10 min each) Akihisa Yamamoto (Physics, biology) Ryo Namba (Physics) Christy Kelly (Mathematics, physics) Rumi Hasegawa (Physics) Jose Gutierrez (Biology) 13:40-13:50 (10 min) at meeting room on the 4th floor, Main Research Building Brief overview of iTHEMS and RIKEN programmes (T.Hatsuda, C.Beauchemin, or T. Tada) (e.g., JRA, IPA, SPDR, RS/SRS) 13:50-14:00 (10 min) Bathroom break 14:00-14:15 (15 min) at meeting room on the 4th floor, Main Research Building (tentative) Short statements by Prof. Jun Nomura and ASCENT program coordinators Qian Wang and Hina Morishige 14:15-16:00 (105 min) at Common Space in the 4th floor of Main Research Building (tentative) Informal discussions among ASCENT program students and iTHEMS members over some snacks and coffee. iTHEMS members will spread at different areas in the common space of 3rd floor and will display posters or conduct activities that can facilitate discussion. If posters are used, they may be the ones used in the Now & Next or new ones.

会場: 研究本館 4階 435-437号室

イベント公式言語: 英語

MACS SG学生訪問

2024年9月2日(月) - 3日(火)

9月2日（月） 13:20〜13:30オープニング 13:30〜13:40 自己紹介 13:40〜14:10 iTHEMS 紹介 14:10〜14:30 コーヒーブレイク 14:30〜15:30 iTHEMS所属の研究者によるセミナー(森脇さん) 16:30〜18:00 研究室訪問(風間研) 18:30〜20:00 研究発表会/懇親会 9月3日（火） 10:00〜10:20 iTHEMS 施設見学 10:40〜12:10 研究室訪問(多々良研) 12:20〜13:20 昼食/コーヒーブレイク 13:30〜15:00 研究室訪問(玉川研) 15:30〜17:00 研究室訪問(磯村研) 17:20〜17:30 クロージング

会場: セミナー室 (359号室)

イベント公式言語: 日本語

What will Happen to iTHEMS⊗Masason Foundation Members?

2024年8月2日(金) 13:30 - 17:30

会場: セミナー室 (359号室)

イベント公式言語: 英語

iTHEMS NOW & NEXT 2024

2024年7月19日(金) 9:30 - 18:00

9:30-10:00 Keynote by Lucy Mcneill 10:00-10:30 Keynote by Jose Said Gutierrez Ortega 10:35-11:05 Keynote by Puttarak Jai-akson 11:05-11:35 Keynote by Kannaka Kazuki 11:35-12:30 Lunch Time Session 12:30-13:30 Working Group / Study Group Report 
13:30-15:30 Flash Talk & Poster Presentation Part 1 
15:30-17:30 Flash Talk & Poster Presentation Part2 17:30 Concluding Remarks by the Director 18:00 reception

会場: 理化学研究所和光キャンパス 本部棟2階大会議室 (メイン会場) / via Zoom

イベント公式言語: 英語

SLMath Summer Graduate School "h-principle"

2024年7月1日(月) - 12日(金)

会場: 東北大学片平キャンパス 知の館

イベント公式言語: 英語

New horizons in immersive visualization at iTHEMS

2024年3月14日(木) 14:00 - 16:00

ジル・フェラン (Adjunct Professor, Department of Physics and Astronomy, University of Manitoba, Canada)

Visualization is an essential part of research, both to explore one’s data and to communicate one’s findings with others. Data that are 3-dimensional can be explored in a more natural way using virtual reality devices. iTHEMS recently purchased new VR headsets with advanced capabilities (Meta Quest Pro). The meeting will start with a general introduction to the current state of the VR space. Then, participants may individually experience a demonstration with the new headsets (showing research done at the ABBL on supernovae and their remnants). There will be ample time for questions and discussions. Come and discover how such tools can be used to enhance our research.

会場: 研究本館 3階 共有スペース

イベント公式言語: 英語

Seoul National University student group visit

2024年1月10日(水) 14:00 - 20:00

カトゥリン・ボシゥメン (理化学研究所 数理創造プログラム (iTHEMS) 副プログラムディレクター)
田中 章詞 (理化学研究所 革新知能統合研究センター (AIP) 上級研究員)
辰馬 未沙子 (理化学研究所 数理創造プログラム (iTHEMS) 研究員)
難波 亮 (理化学研究所 数理創造プログラム (iTHEMS) 上級研究員)
金 東昱 (理化学研究所 数理創造プログラム (iTHEMS) 特別研究員)
シュテッフェン・バッケス (理化学研究所 数理創造プログラム (iTHEMS) 上級研究員)

A group of 22 undergraduate students in the GLEAP programme at Seoul National University will visit iTHEMS to hear short talks by our members, exchange one-on-one, and visit our facilities. I would like to encourage all available iTHEMS members to take part in this event which will be held in different spaces throughout the day, all at the RIKEN Wako campus Main Research Building: 15:50-16:10 at iTHEMS Common Room (#246-248) Coffee break with iTHEMS members and SNU visitors 16:10-17:50 on 4th floor, room #435-437 Short talks by iTHEMS members 18:05-18:30 in 3rd floor common space Short intro talks by SNU visitors 18:30-20:00 in 3rd floor common space Free informal discussion between SNU visitors and iTHEMS members over some light food [Note some slight changes in the times previously announced]

会場: 研究本館 3階 共有スペース / 研究本館 435-437号室 / コモンルーム (246-248号室)

イベント公式言語: 英語

First Chalk

2023年3月29日(水) 16:30 - 17:00

The occasion to celebrate the launch of the new seminar room will take place after iTHEMS NOW & NEXT.

会場: セミナー室 (359号室)

イベント公式言語: 英語