イベント検索

ABBL-iTHEMS Joint Seminars (Following r-EMU seminar 13:30-15:00)

2019年5月31日(金) 15:15 - 17:35

15:15-15:35 Hiroyuki Sagawa (ICRR, U.Tokyo) “Recent TA Results and the extension status for the study of the highest-energy cosmic rays” 15:35-16:30 Igor Tkachev (Russian Academy of Sciences) “Axion stars: from birth to death” 16:30-16:40 Break 16:40-17:35 Peter Tinyakov (U. Libre de Bruxelles) “Solar mass black holes and dark matter"

会場: 研究本館 435-437号室

イベント公式言語: 英語

RIKEN iTHEMSのアウトリーチについての研究会 2019

2019年5月31日(金) - 6月3日(月)

「ジャーナリストと研究者の双方向的関係の構築」のため、「ジャーナリストが科学教育、研究の現場に出来るだけ長期間滞在する」という「ジャーナリスト・イン・レジデンス・プログラム」が2010年度に数理科学分野で始まり、2017年度まで毎年行われています。これは数学の研究を外部から見てもらい、将来的には社会と数学を近づけようという試みです。今回は、これまでの「ジャーナリスト・イン・レジデンス・プログラム」による交流の実績の上で、2016年11月に始動した理化学研究所の数理創造プログラムの研究と社会の関連付けを探るとともに、今後のジャーナリストと研究者の双方向的関係の構築のための議論を行います。 会場：東京大学玉原国際セミナーハウス 群馬県沼田市上発知町玉原高原 当日の電話 FAX 0278-23-9836 世話人: 坪井 俊 理化学研究所 数理創造プログラム 副プログラムディレクター

会場: 東京大学玉原国際セミナーハウス

イベント公式言語: 日本語

Certain invariants as dimension

2019年5月24日(金) 16:00 - 18:10

大内 元気 (理化学研究所 数理創造プログラム (iTHEMS) 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. Abstract: In this talk, I would like to talk about certain invariants that look like dimension. This talk has independent two parts. In part 1, I will talk about finite metric spaces. In 2013, Leinster introduced the notion of magnitude of finite metric spaces. It measures effective number of points in finite metric spaces. Considering magnitude and scale transformation, Leinster and Willerton defined dimension of finite metric space with scale. I will explain the definition of magnitude of finite metric spaces and see examples. In part 2, I will talk about derived categories of smooth projective varieties or finite dimensional algebras. In 2014, Dimitrov, Heiden, Katzarkov and Kontsevich introduced the notion of entropy of endofunctors of derived categories. It measures complexity of endofunctors under iteration. Serre functor is an autoequivalence of derived category, that describes Serre duality. Entropy of Serre functor looks like dimension of derived categories. I will talk about known results for entropy of Serre functors and some related topics.

会場: セミナー室 (160号室)

イベント公式言語: 英語

Introduction to Singularity Theory in Algebraic Geometry

2019年5月16日(木) 16:00 - 18:10

佐藤 謙太 (理化学研究所 数理創造プログラム (iTHEMS) 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

Gauge theory and symmetries of 4-dimensional spaces

2019年4月26日(金) 16:00 - 18:10

今野 北斗 (理化学研究所 数理創造プログラム (iTHEMS) 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 (理化学研究所 数理創造プログラム (iTHEMS) 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

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 基礎科学特別研究員)

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

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

核データと重元素合成を中心とする宇宙核物理研究会

2019年3月6日(水) - 8日(金)

原子核物理、宇宙物理、天文観測、宇宙化学、素粒子物理等の広い分野からの会員を持つ宇宙核物理連絡協議会（宇核連）は、2008年の発足以来中長期研究戦略策定を考慮に入れた分野横断的ワークショップ・研究会を適宜開催してきました。2014年度RCNPで開催した「宇宙核物理の現状と将来」をテーマとする研究会では、継続的研究会開催への強い要望がうまれ、その後「元素合成」、「X線天体と元素合成」をテーマに国立天文台、理化学研究所を会場として会を重ねてまいりました。 今年度は元素合成研究への核データのインパクトを俯瞰するとともに、重力波プローブによる新たな重元素生成研究の発展を期して、「核データと重元素合成」をテーマに2.5日間の研究会を予定しています。核データ分野の発展を議論する上で、分野の活動を支え、推進してきた北海道大学、附属原子核反応データベース研究開発センター（JCPRG）との共催で、北海道大学で開催いたします。

会場: 北海道大学学術交流会館

イベント公式言語: 日本語

Tropical Rain Forest

2019年2月21日(木) 15:30 - 17:00

佐竹 暁子 (九州大学 大学院理学研究院 数理生物学研究室 教授)

In a unique phenomenon restricted to the tropical rain forests in Southeast Asia, hundreds of plant species from dozens of families reproduce synchronously at irregular, multi-year intervals. Although several hypotheses have been proposed, the proximate environmental cues that synchronize these general flowering events are uncertain. Fortunately, accumulation of long-term data and advanced statistical and modeling techniques are starting to shed new light on phenology of tropical plants. In this talk, series of studies that integrate long-term field monitoring, gene expression analyses, and modeling will be presented.

会場: 大河内記念ホール

配信:計算科学研究棟 311会議室 / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

イベント公式言語: 英語

RIKEN-Berkeley WS on Quantum Information Science (RB19)

2019年1月25日(金) - 29日(火)

Initiated by the RIKEN Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program at Berkeley, this workshop will focus on the development of quantum computing techniques, quantum materials, and quantum sensing, as well as their corresponding applications to physical sciences, with an emphasis to galvanize the participants into future collaboration. Organizing Committee: Chia Cheng Chang (RIKEN iTHEMS/UCB/LBNL NSD) Takumi Doi (RIKEN iTHEMS) Tetsuo Hatsuda (RIKEN iTHEMS) Wick Haxton (UCB/LBNL NSD/RIKEN iTHEMS) Alan Poon (LBNL NSD/BQ) Advisory Committee: Jonathan Carter (LBNL CRD/BQ) Yasunobu Nakamura (RIKEN CEMS/Tokyo) Franco Nori (RIKEN/Michigan) Thomas Schenkel (LBNL AT-AP/BQ) Irfan Siddiqi (UCB/BQ) Seigo Tarucha (RIKEN CEMS/Tokyo) Co-hosted by RIKEN iTHREMS　 RIKEN CEMS　 Lawrence Berkeley National Lab. (LBNL)　 Univ. of California at Berkeley (UCB)　 Supported by Berkeley Quantum (bq)　 US Dept. of Energy (DOE)　

会場: Lawrence Berkeley National Laboratory (Berkeley, California)

イベント公式言語: 英語

Biology Seminar

2018年12月13日(木) 14:00 - 16:00

風間 裕介 (理化学研究所 仁科加速器科学研究センター (RNC) 植物ゲノム進化研究チーム チームリーダー)
ジェフリ・フォーセット (理化学研究所 数理創造プログラム (iTHEMS) 上級研究員)

Speaker: Jeffrey Fawcett (iTHEMS) Title: Introduction to Genomics Abstract: The genetic information, or the genome, of almost all species are determined by the order (i.e. the "sequence") of millions of nucleotides represented by A, G, C, and T. I will first outline what we already know about the genome, how they differ across species and individuals, and how we can study them. I will then briefly introduce "3D Genomics", a topic that is becoming quite hot in biology now: the genome is not only a one dimensional "sequence" information but the chromosomes must be folded up to fit into the cell nuclei, and this 3D structure of the chromosome and the spatial positioning of the genes might be important for the biology of each species. Speaker: Yusuke Kazama (Nishina Center) Title: 大きな玉ほど大きく壊す：シロイヌナズナを用いて明らかにした重イオンビーム変異の特徴 Abstract: 重イオンビームはγ線やX線よりも線エネルギー付与（LET)が高いことで知られ、核種やビームの速度を選択することによりLETを調節して照射することもできる。私たちは、モデル植物シロイヌナズナを用いてLETが変異誘発に与える影響を調べ、変異率が最大となるLET＝30.0 keV/μm(LETmax)を発見した。突然変異体の全ゲノム解析を行ない、LETmaxでは塩基置換や小さい欠失が多いのに対し、LET=290 keV/μmでは大きな欠失や染色体再編成の頻度が高いことを明らかにした。目的や材料に合わせて「高効率で1遺伝子を破壊するにはLETmax照射」を、「2遺伝子以上の破壊や染色体再編成の誘発には高LET照射」を行うオンデマンド照射技術を確立した。今後は、染色体再編成が植物の形質に与える影響を、3Dゲノム構造の変化、クロマチン構造の変化、遺伝子発現の変化に注目して研究していきたい。

会場: セミナー室 (160号室)

イベント公式言語: 英語

Workshop on Recent Developments of Chiral Matter and Topology

2018年12月6日(木) - 9日(日)

The aim of this workshop is to gather researchers of high-energy and condensed-matter physics working on chiral Matter and Topology, to exchange ideas and establish collaborations to tackle unsolved issues and carry out future extensions. The workshop expects to welcome 40-60 participants who are interested in the aforementioned topics. Organizers: Tomoki Ozawa, Tetsuo Hatsuda (RIKEN iTHEMS) Di-Lun Yang (RIKEN Nishina Center; YITP, Kyoto) Chang-Tse Hsieh (Kavli IPMU / ISSP, the Univ. of Tokyo) Jiunn-Wei Chen, Guang-Yu Guo (National Taiwan Univ.) Hsiang-Nan Li (Academia Sinica)

会場: National Taiwan University, Taipei, Taiwan

イベント公式言語: 英語

International Symposium on Quantum Fluids and Solids (QFS)

2018年7月25日(水) - 31日(火)

The International Symposium on Quantum Fluids and Solids (QFS) will be held at Ito International Research Center (IIRC) on Hongo campus of the University of Tokyo, Japan, from July 25 through 31, 2018. One of the sponsors of this conference is iTHEMS. The QFS series started forty-three years ago making it one of the oldest series of international conferences in the field of low temperature physics. It has historically been focusing on physics of liquid and solid helium and hydrogen. But in this century its scope is expanding widely from laser cooled cold atoms to topological matters. At QFS2018 in Tokyo, this trend will be continued and with even more interdisciplinary aspects emphasized between the traditional subjects and those in broader physical systems.

会場: 東京大学 本郷キャンパス 伊藤国際学術研究センター

イベント公式言語: 英語

Bell's Theorem, Entanglement, Quantum Teleportation and All That

2018年7月19日(木) 16:00 - 17:30

Anthony James Leggett (Professor, University of Illinois at Urbana-Champaign, USA)

iTHEMS-CEMS Joint Colloquium. Professor Leggett is widely recognized as a world leader in the theory of low-temperature physics, and his pioneering work on superfluidity was recognized by the 2003 Nobel Prize in Physics. Abstract: One of the most surprising aspects of quantum mechanics is that under certain circumstances it does not allow individual physical systems, even when isolated, to possess properties in their own right. This feature, first clearly appreciated by John Bell in 1964, has over the last half-century been tested experimentally and found (in most people's opinion) to be spectacularly confirmed. More recently it has been realized that it permits various operations which are classically impossible, such as "teleportation" and secure-in-principle cryptography. This talk is a very basic introduction to the subject, which requires only elementary quantum mechanics.

会場: 大河内記念ホール

配信:計算科学研究棟 311会議室 / SUURI-COOL (Kyoto) / 東北大学 AIMR本館 2階セミナー室

イベント公式言語: 英語

iCeMS-iTHEMS Joint Workshop on Interdisciplinary Biology

2018年7月4日(水) 10:00 - 16:30

This is the first joint workshop between iCeMS (Kyoto Univ.) and iTHEMS (RIKEN). The WS is co-hosted by KUIAS (Kyoto Univ.), iTHEMS (RIKEN) and MACS Program (Kyoto Univ.). By exploring the forefront of experimental and mathematical biology, this workshop aims to stimulate novel research directions in these areas and strengthen the connection between Kyoto Univ. and RIKEN. Those who plan to attend the "get-together", please register before June 22 (Fri.) noon. Co-hosted by Kyoto University Institute for Advanced Study (KUIAS), Kyoto Univ. Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN MACS Program (MACS), Kyoto Univ.

会場: 京都大学 北部総合教育研究棟 201号室

イベント公式言語: 英語

Systems Biology of Cellular Rhythms

2018年7月2日(月) 15:00 - 16:30

Albert Goldbeter (Professor, Unit of Theoretical Chronobiology, Faculty of Sciences, Université Libre de Bruxelles, Belgium)

Rhythmic phenomena occur at all levels of biological organization, with periods ranging from milliseconds to years. Among biological rhythms, circadian clocks, of a period close to 24h, play a key role as they allow the adaptation of living organisms to the alternation of day and night. Biological rhythms represent a phenomenon of temporal self-organization in the form of sustained oscillations of the limit cycle type. Mathematical models show how the emergent property of oscillatory behavior arises from molecular interactions in cellular regulatory networks, which explains why cellular rhythms represent a major research topic in systems biology. After providing an introduction to biological rhythms and their modeling, I will focus on mathematical models for two major examples of rhythmic behavior at the cellular level : the circadian clock and the cell cycle. The coupling of these rhythms allows for their synchronization and for the occurrence of more complex patterns of oscillatory behavior. I will discuss the reasons why models for cellular rhythms tend to become more complex, upon incorporating new experimental observations. The case of cellular rhythms allows us to compare the merits of simple versus complex models for the dynamics of biological systems.

会場: 鈴木梅太郎記念ホール

配信:計算科学研究棟 305-2会議室 / SUURI-COOL (Kyoto) / 東北大学 AIMR本館 2階セミナー室

イベント公式言語: 英語

相対かつ同変ラグランジアンフレアーホモロジーとアティヤ-フレアー予想

2018年6月19日(火) 14:30 - 16:00

深谷 賢治 (理化学研究所 数理創造プログラム (iTHEMS) 客員主管研究員 / Permanent Member, Simons Center for Geometry and Physics, Stony Brook University, New York, USA)

アティヤ-フレアー予想は、 ゲージ理論におけるフレアーホモロジーとラグランジアンフレアーホモロジーの間の関係に関するものである。 その一つの困難は、ラグランジアンフレアーホモロジーを考えるシンプレクティック多様体が特異点を持つことである。双対かつ同変ラグランジアンフレアーホモロジーを考えることで、この困難が解消し、少なくともアティヤ-フレアー予想を数学的に厳密な予想として定式化できることを説明する。 RIKEN iTHEMS、東京大学数理科学研究科トポロジー火曜セミナー共催

会場: 東京大学数理科学研究科数理科学研究科棟 056号室

イベント公式言語: 日本語