宇宙はいかに始まったのかーインフレーション理論とその実証に向けた歩みー

2019年5月21日(火) 15:00 - 16:30

佐藤 勝彦 (東京大学 名誉教授 / 独立行政法人日本学術振興会 学術システム研究センター 所長)

インフレーション宇宙論の提唱者として知られる佐藤勝彦名誉教授による特別講演です。

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: 日本語

Introduction to Singularity Theory in Algebraic Geometry

2019年5月16日(木) 16:00 - 18:10

佐藤 謙太 (数理創造プログラム 基礎科学特別研究員)

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. In this talk, I will explain for all scientists how singularities are studied in algebraic geometry. In algebraic geometry, we study algebraic varieties, which are figures defined as the zero sets of polynomial equations. To study an algebraic variety, we often expect that the variety is smooth, that is, the variety locally resembles Euclidian spaces. However, even if we start from smooth varieties, we sometimes encounter non-smooth varieties. This is one of the reasons why we need to study singularities. Part I: In the first one hour, I will explain how singularities are studied. I will introduce two invariants of singularities by which we can compare singularities numerically. One invariant is defined in terms of resolution of singularities and the other is defined in terms of positive characteristic methods. I also explain a surprising relation of these invariants. Part II: In the second one hour, I will explain how singularity theory is used to study smooth projective varieties. I will introduce Minimal Model Program and explain the relation with singularity theory.

会場: セミナー室 (160号室)

イベント公式言語: 英語

Introduction to Quantum Computation

2019年5月13日(月) - 15日(水)

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

The schedule of the lectures on "Quantum Computation" by Dr. Shunji Matsuura (1QBit) is as follows. May 13 (Mon) [Lecture 1] 10:00-11:30, [Lecture 2] 14:00-15:30 May 14 (Tues) [Lecture 3] 10:00-11:30, [Lecture 4] 14:00-15:30 May 15 (Wed) [Lecture 5] 10:00-11:30, [Lecture 6] 14:00-15:30

会場: 仁科ホール

イベント公式言語: 英語

Three quantizations of conformal field theory

2019年5月1日(水) 15:40 - 17:30

多田 司 (数理創造プログラム コーディネーター / 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 副主任研究員)

Needless to say, conformal field theory is elemental in the study of string theory, statistical quantum systems, and various quantum field theories. Two-dimensional conformal field theory is usually quantized by the so-called radial quantization. However, this is not the only way. As a matter of fact, there are two other distinctive choices for the time foliation, or equivalently, the Hamiltonian. One of these choices yields the continuous Virasoro algebra, while the other choice leads to the Virasoro algebra on a torus. The former case corresponds to the recently found (and perhaps less known) phenomenon, sine-square deformation. The latter yields the well-known entanglement entropy. I will present a comprehensive treatment of these three quantizations and discuss its physical implications.

会場: Old LeConte Hall 402, UC Berkeley

イベント公式言語: 英語

Gauge theory and symmetries of 4-dimensional spaces

2019年4月26日(金) 16:00 - 18:10

今野 北斗 (数理創造プログラム 基礎科学特別研究員)

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. Although the term "gauge theory" is usually used in physical contexts, in the early 1980's, mathematicians found that gauge theory has many striking applications to purely mathematical problems. Most of typical applications are related to topology of 4-dimensional spaces. As a recent development in this direction, I used gauge theory to study "the shape of the space of all symmetris of a 4-dimensional space". In the first one hour, I will explain a notion of mathematical spaces, called manifolds, and try to describe the idea: how mathematicians make use of gauge theory to study the topology of a 4-dimensional manifold. In the second one hour, I will explain what the space of symmetries of a manifold means, and which type of theorems about the space of symmetries can be obtained using gauge theory.

会場: セミナー室 (160号室)

イベント公式言語: 英語

Quantum computing: current status and prospects

2019年4月25日(木) 15:00 - 16:30

藤井 啓祐 (大阪大学 大学院基礎工学研究科 教授)

Supported by extensive experimental efforts for realization of quantum computing devices, quantum computers of a hundred qubits are now within reach in the near future. This level of a quantum computer is not enough for fully fledged fault-tolerant quantum computing, but is still expected to have computational advantage against classical computers. Such a noisy intermediate scale quantum computing (NISQ) device is thought to be a testbed for proof-of-principle experiments of quantum algorithms and verification of quantum physics in the limit of extremely high complexity. In this talk, I will provide a general introduction to quantum computing starting from how and for what quantum computers work. Then I will provide an overview of the current status and prospects of the field of quantum computing. As the final part, I will also talk about our own activities on quantum-classical hybrid algorithm, which is a kind of quantum algorithms specifically designed for the NISQ devices.

会場: 鈴木梅太郎記念ホール

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

Introduction to Galois Theory and Class Field Theory

2019年4月18日(木) 16:00 - 18:00

宮﨑 弘安 (数理創造プログラム 基礎科学特別研究員)

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. Part I: Galois theory is one of the most important theories in mathematics. Speaking in one phrase, it explains the correspondence between “extensions of numbers” and “subgroups of Galois group”. Basically, finding subgroups of a finite group is much easier than finding extensions of numbers. As a result, Galois theory has incredibly strong applications. For example, we can prove polynomial equations of degree greater than 4 are not always solvable by radicals, which is a celebrated result by Abel and Galois. In the first part of the talk, I will introduce Galois theory in an accessible way for all scientists. Part II: Class Field Theory (CFT) is a monumental work in number theory. Given Galois theory, which is explained in Part I, classifying “extension of numbers” is reduced to classifying “subgroups of Galois group”. So, the next thing to do would be to analyze the structure of Galois groups. CFT enables us to describe the Galois group of a number field K by using only the language of K, i.e., not by using its extensions. In the second part of the talk, I will explain CFT in an as accessible way as possible for all scientists (in particular, also for mathematicians). If time permits, I would like to explain a geometric interpretation of Galois theory, and higher dimensional CFT.

会場: セミナー室 (160号室)

イベント公式言語: 英語

International Molecule-type Workshop "Frontiers in Lattice QCD and related topics"

2019年4月15日(月) - 26日(金)

International Molecule-type Workshop "Frontiers in Lattice QCD and related topics" will be held in Yukawa Institute for Theoretical Physics (YITP) on April 15 - 26, 2019 under the support of iTHEMS and YITP. Lattice quantum chromodynamics (QCD) is a systematic method to investigate strong interaction of hadrons with numerical simulations. In this workshop, frontiers of lattice QCD will be discussed under relaxed atmosphere in Kyoto. Organizers: Sinya Aoki (YITP), Yasumichi Aoki (RIKEN, CCS), Hidenori Fukaya (Osaka U.), Shoji Hashimoto (KEK), Tetsuo Hatsuda (RIKEN, iTHEMS), Takumi Doi (RIKEN, Nishina Center), Atsushi Watanabe (YITP)

会場: 京都大学基礎物理学研究所

イベント公式言語: 英語

第8回 MACSコロキウム・2019年度MACS 学生説明会

2019年4月12日(金) 15:00 - 17:30

千葉 逸人 (東北大学 材料科学高等研究所 (AIMR) 教授)

15:00- ティータイム・団らん 15:15- 千葉 逸人 博士 「同期現象の数理」 16:45- 2019年度MACS学生説明会 第8回MACSコロキウムは（iTHEMS協賛）です。理研和光への配信がありますが、可能な方は是非京都で参加してください。おいしいスイーツもありますよ。

会場: 京都大学 理学部 6号館 401講義室

配信:研究本館 2階 235号室

イベント公式言語: 日本語

ABBL, iTHEMS, r-EMU Joint Seminar: Impacts of New Carbon Fusion Cross Sections on Type Ia Supernovae

2019年4月12日(金) 15:00 - 16:00

森 寛治

会場: セミナー室 (132号室)

イベント公式言語: 英語

公開鍵暗号概論（第10回）

2019年4月9日(火) 13:30 - 15:30

エレン・メフメット・クラル (数理創造プログラム 客員研究員 / 上智大学 理工学部 客員研究員（JSPS特別研究員）)

会場: セミナー室 (160号室)

イベント公式言語: 英語

iTHEMS Seminar+discussion on "non-equilibrium physics of living matter"

2019年4月8日(月) 14:00 - 15:30

川口 喬吾 (東京大学 / 理化学研究所 生命機能科学研究センター (BDR) 生体非平衡物理学理研白眉研究チーム 理研白眉研究チームリーダー)
足立 景亮 (理化学研究所 生命機能科学研究センター (BDR) 生体非平衡物理学理研白眉研究チーム 研究員)

14:00-14:50 (40 min. talk + 10 min discussion) "Physical" problems in multicellular dynamics and cell differentiation Kyogo Kawaguchi (RIKEN Hakubi Research Group) 14:50-15:30 (30 min. talk + 10 min. discussion) Phase transition in a chromatin model with epigenetic modification Kyosuke Adachi (Kawaguchi Lab.) 15:30- Informal discussions

会場: セミナー室 (160号室)

イベント公式言語: 英語

Lifting low dimensional local systems

2019年4月3日(水) 15:45 - 16:45

De Clercq Charles (Université Paris 13, Sorbonne, France)

The content of this seminar is basically for mathematicians (sorry). If you are interested in how a professional math seminar works, please feel free to join! A long-standing conjecture predicts the existence of lifts for Galois representations with F_p coefficients to p-adic coefficients. The case 2-dimensional representations of the absolute Galois group of Q is closely related to Serre's modularity conjecture, proved by Khare and Witenberger. After some recollection on the state of the art about this problem, i will develop the machinery underneath the notion of smooth profinite groups. We will then show how this machinery allows to prove some lifting theorems for low dimensional Galois representations and local systems, getting out of the classical arithmetic world usually considered for this conjecture.

会場: セミナー室 (160号室)

イベント公式言語: 英語

The Origin of the X-ray Clumpy Ejecta in Type Ia Supernova Remnants

2019年4月3日(水) 14:00 - 15:00

佐藤 寿紀 (理化学研究所 開拓研究本部 (CPR) 玉川高エネルギー宇宙物理研究室 基礎特別研究員)

X-ray-emitting clumpy structures are generally observed in young Type Ia supernova remnants although the origin is still obscure. There are two candidates for explaining the formation of clumps; initial clumpiness in ejecta at the explosion (i.e., clumpy ejecta model) or hydrodynamic instabilities made from smooth ejecta profile (i.e., smooth ejecta model). This information should reflect the initial ejecta structure of SNe Ia, so it is important for understanding the Type Ia explosion itself. Our preliminary investigations into constraining the structure of SN Ia remnants using Fourier and wavelet-transform analyses did not turn out to be sufficiently powerful at discriminating the two hydro models and the observed Tycho image from each other. This led us to investigate an approach that would be more sensitive to patterns in the distribution of clumps and holes in the images, such as the "genus statistic.” In this study, for the first time, the genus statistics have been applied to a famous type Ia remnant, Tycho (SN 1572) to understand the formation of the clumps by comparing with hydrodynamical models (Sato et al. 2019, arXiv: 1903.00764). We found the genus curve from Tycho's supernova remnant strongly indicates a skewed non-Gaussian distribution of the ejecta clumps, which is similar to that of a hydrodynamical model for the clumpy ejecta model. In contrast, a hydrodynamical model for the smooth ejecta model has a genus curve that is similar to that of a random Gaussian distribution. Thus, our results support the initial clumpiness in the Type Ia ejecta is more reasonable for the origin of the clumps and demonstrate usefulness of the genus statistics for this field. In addition, we will also discuss the origin of “Fe-rich” ejecta clumps in Type Ia SNRs in this seminar.

会場: 研究本館 433号室

イベント公式言語: 英語

Tensor Berry connections and their topological invariants

2019年4月2日(火) 14:00 - 15:00

ジャンドミニコ・パルンボ (Researcher, Université Libre de Bruxelles, Belgium)

The Berry connection plays a central role in our description of the geometric phase and topological phenomena. In condensed matter, it describes the parallel transport of Bloch states and acts as an effective "electromagnetic" vector potential defined in momentum space. Inspired by developments in high-energy physics, where higher-form Kalb-Ramond gauge fields were introduced, I hereby explore the existence of "tensor Berry connections" in quantum matter. My approach consists in a general construction of effective gauge fields, which I ultimately relate to the components of Bloch states. I apply this formalism to various models of topological matter, and I investigate the topological invariants that result from generalized Berry connections. I introduce the 2D Zak phase of a tensor Berry connection, which I then relate to the more conventional first Chern number; I also reinterpret the winding number characterizing 3D topological insulators to a Dixmier-Douady invariant, which is associated with the curvature of a tensor connection. Besides, my approach identifies the Berry connection of tensor monopoles, which are found in 4D Weyl-type systems in ultracold atoms.

会場: セミナー室 (160号室)

イベント公式言語: 英語

iTHEMS-AIMR連携ワークショップ「医学と数理の接するところ」

2019年3月29日(金) 10:00 - 17:00

主催：SUURI-COOL Sendai（iTHEMS-AIMR数理連携研究室） 共催：理化学研究所iTHEMS､東北大学AIMR 協力：JST-CREST「臨床医療における数理モデリングの新たな展開」 講演者： 植田 琢也 MD, Ph.D（東北大学病院） 小川 軌明 Ph.D（理化学研究所iTHEMS） 坂上 貴之 Ph.D（京都大学数学教室） 杉谷 宜紀 Ph.D（東北大学AIMR） 清田 純 MD, Ph.D（理化学研究所MIH） 関根 鉄朗 MD, Ph.D（日本医科大学病院） 瀧 雅人 Ph.D（理化学研究所iTHEMS） 滝沢 研二 Ph.D（早稲田大学理工学術院） 敬称略、50音順。講演は日本語で行われます。 オーガナイザー： 東北大学AIMR 水藤 寛 理化学研究所数理創造プログラム(iTHEMS) 初田 哲男

会場: 東北大学片平キャンパス・知の館3階 Lecture Theater

イベント公式言語: 日本語

AI Smart Robot Network

2019年3月22日(金) 15:00 - 17:00

大田 佳宏 (東京大学 / Arithmer株式会社)

Arithmer Inc. is a startup company providing with business solutions in the field of AI / machine learning / robotics, which emerged from Mathematical Science Dep., Univ. of Tokyo. I will present our recent success stories and ambitious attempts in which applied mathematics is fully utilized, such as optical character recognition, automatic artificial tooth design, scoring driver's skill from movie, and image measurement of human body.

会場: 統合支援施設（第一食堂） 2階 大会議室

配信:計算科学研究棟 R311

イベント公式言語: 日本語

Value distribution of zeta and L-functions and related topics

2019年3月22日(金) - 27日(水)

March 22–26, 2019 Main Conference (invited talks, posters and a limited number of short contributed talks) Welcome Reception: March 22, 2019 (18:00~20:00) Conference Dinner: March 25, 2019 (18:30~21:00) March 27, 2019 (9:30~17:00) One-day Workshop (a series of short contributed talks by young researchers to facilitate active discussions) ORGANIZING COMMITTEE Ade Irma Suriajaya (RIKEN) Yoshinosuke Hirakawa (Keio University) Masataka Ono (Kyushu University) Shin-ichiro Seki (Tohoku University) Keiju Sono (Ehime University) Shingo Sugiyama (Nihon University) Yuta Suzuki (Nagoya University) ADVISORY COMMITTEE Tetsuo Hatsuda (RIKEN iTHEMS) Kenichi Bannai (Keio University, RIKEN AIP Center)

会場: 大河内記念ホール / 統合支援施設（第一食堂） 2階 大会議室

イベント公式言語: 英語

ZetaValue2019-iTHEMS Special Mathematics Colloquium

2019年3月21日(木) 14:00 - 17:30

松本 耕二 (名古屋大学 教授)
Jörn Steuding (University of Würzburg, Germany)

Prof. Kohji Matsumoto (Nagoya University) "An overview of the theory of multiple zeta-functions" Multiple zeta-functions are generalizations of the Riemann zeta-function, and its theory has been rapidly developed in these decades. It is connected with various fields of mathematics and mathematical physics. In this talk I will give an overview of some part of recent developments, mainly from the analytic viewpoint. Prof. Jörn Steuding (University of Würzburg, Germany) "On the Infinite in Number Theory" Beginning with two simple examples from elementary number theory (one of diophantine origin and one of arithmetical nature), we discuss the role of “infinity” in number theory. We touch upon topics like how to find good rational approximations to irrational quantities and the distribution of prime numbers. We conclude with a motivation of the big open question in this field, namely, the Riemann hypothesis (one of the six unsolved millennium problems) and the Langlands program.

会場: 大河内記念ホール

イベント公式言語: 英語

Machine Learning for Intelligent Multiscale Modeling of Platelet Dynamics

2019年3月19日(火) 15:00 - 17:00

Yuefan Deng (Professor, Applied Mathematics Department, Stony Brook University, USA)

Multiscale modeling in biomedical engineering is gaining momentum because of progress in supercomputing, applied mathematics, and quantitative biomedical engineering. For example, scientists in various disciplines have been advancing, slowly but steadily, the simulation of blood including its Olowing and the physiological properties of such components as red blood cells, white blood cells, and platelets. Platelet activation and aggregation stimulate blood clotting that results in heart attacks and strokes causing nearly 20 million deaths each year. To reduce such deaths, we must discover new drugs. To discover new drugs, we must understand the mechanism of platelet activation and aggregation. To model platelets’ dynamics involves setting the basic space and time discretization in huge ranges of 5-6 orders of magnitudes, resulting from the relevant fundamental interactions at atomic, to molecular, to cell, to Oluid scales. To achieve the desired accuracy at the minimal computational costs, we must select the correct physiological parameters in the force Oields such as the Morse potential and Hooke’s law as well as the spatial and temporal discretization, by machine learning. We demonstrate our preliminary results of speeding up a multiscale two-platelet aggregation simulation, while maintaining sufOicient accuracy, by nearly one order of magnitude, compared with traditional algorithm that uses the smallest of all temporal and spatial scales in order to capture the Oinest details of the dynamics. We present our analyses of the accuracies and efOiciencies of the representative modeling. We will also outline the general methodologies of multiscale modeling of cells at atomic resolutions.

会場: 研究本館224-226室

イベント公式言語: 英語