Functional Renormalization Group at RIKEN 2023 -From condensed matter and particle physics to gravity-

2023年1月21日(土) - 22日(日)

ゲルゲイ・フェヨシュ (Assistant Professor, Institute of Physics, Eötvös Loránd University, Hungary)
谷崎 佑弥 (理化学研究所 仁科加速器科学研究センター (RNC) 理論研究グループ 基礎科学特別研究員 / 京都大学 基礎物理学研究所 助教)
横田 猛 (東京大学 物性研究所 特別研究員)
春名 純一 (京都大学 大学院理学研究科 博士課程)
‪田財 里奈 (京都大学 基礎物理学研究所 助教)
藪中 俊介 (日本原子力研究開発機構 研究員)
芳賀 大樹 (大阪公立大学 大学院工学研究科 電子物理系専攻 助教)
山田 雅俊 (Assistant Professor, College of Physics, Jilin University, China)

Functional renormalization group (FRG) is a powerful theoretical tool to investigate physical systems described by field theory. Its application covers diverse areas of physics spanning from condensed matter and statistical physics to particle physics and gravity. The purpose of this two-day workshop is to overview the recent applications and progresses of FRG in various fields of physics, to discuss future directions, and to seek for possible new collaborations bridging different fields of physics.

会場: 研究本館 3階 345−347号室 (メイン会場) / via Zoom

イベント公式言語: 英語

Math and Physics of Seiberg-Witten theory

2023年1月20日(金) 16:00 - 18:10

飯田 暢生 (東京工業大学 理学院 日本学術振興会 特別研究員 PD)

Math and physics have developed through interactions with each other. For example, classical mechanics and calculous were born together. Einstein's theory of gravitation is written in the language of pseudo-Riemann geometry. Since the late 20th century, physicists centering on Edward Witten have revolutionized modern geometry. Seiberg-Witten theory is one of such breakthroughs, for both mathematicians and physicists. In physics it is regarded as a theory describing strong coupling (i.e. low energy) behavior of some supersymmetric gauge theories. It showes confinement (by a mechanism similar to superconductivity) and electric magnetic duality. Even though this story has not been mathematically justified yet, it is regarded as an important trigger of developments in understanding non perturbative aspects of quantum field theory and string theory, and stimulates broad fields of physics and math. In math, Seiberg-Witten theory is regarded as a fundamental tool to study 3 and 4-dimensional geometry. This is based on a PDE called Seiberg-Witten equation, which originates from the "electric magnetic dual description" of monopoles, but people can use it as a tool to study geometry without knowing such a physical origin. In this talk, developments of Seiberg-Witten theory from both viewpoints will be reviewed and if the time permits, works in math by the speaker and collaborators will be discussed. The speaker thinks it is unusual for a mathematician to talk about something that has not been mathematically justified yet, but hopes this talk will lead to new interactions between math and physics.

会場: コモンルーム 246-248号室 とZoomのハイブリッド開催

イベント公式言語: 英語

Understanding kilonova spectra and identification of r-process elements

2023年1月20日(金) 14:00 - 15:00

土本 菜々恵 (東北大学 大学院理学研究科 天文学専攻 博士課程（学術振興会特別研究員）)

Binary neutron star (NS) merger is a promising site for the rapid neutron capture nucleosynthesis (r-process). The radioactive decay of newly synthesized elements powers electromagnetic radiation, as called kilonova. The detection of gravitational wave from a NS merger GW170817 and the observation of the associated kilonova AT2017gfo have provided with us the evidence that r-process happens in the NS merger. However, the abundance pattern synthesized in this event, which is important to understand the origin of the r-process elements, is not yet clear. In this talk, I will first introduce an overview and current understanding of kilonova. Then, I will discuss our recent findings of elemental features in photospheric spectra of kilonova toward identification of elements.

会場: via Zoom

イベント公式言語: 英語

Mathematical models inspired by the Lenski experiment

2023年1月19日(木) 10:00 - 11:00

Adrian Gonzalez-Casanova (Neyman Visiting Assistant Professor, University of California, Berkeley, USA / Associate Professor, National Autonomous University of Mexico, Mexico)

We will discuss the basic models of mathematical population genetics and see how to apply them to the study of the Lenski experiment. Furthermore, we will describe novel models that are capable of providing a parsimonious explanation of the deceleration of the relative fitness and can be used to attack questions such as, is it advantageous to be efficient? If time permits, we will also discuss examples of mathematical modelling beyond the Lenski experiment, including the study of populations of bacteria carrying plasmids.

会場: via Zoom

イベント公式言語: 英語

Tetra-neutron system studied by RI-beam experiments

2023年1月17日(火) 13:30 - 15:00

下浦 享 (理化学研究所 開拓研究本部 (CPR) 上坂スピン・アイソスピン研究室 研究員)

Multi-neutron systems have attracted a long-standing attention in nuclear physics. In several decades, experimental attempts have been made with a particular focus on the tetra-neutron system. Among them, the two different experiments, the double-charge exchange reaction on 4He and the alpha-particle knockout reaction from the 8He, show a sharp peak just above the threshold in the four-neutron spectra, which could be a signature of a "resonant state", separate from a broad bump structure at higher excitation energy regions. Both the experiments have been realized by using the 8He beam above 150 A MeV at the RIKEN RI Beam Factory. Details of the two experiments including basic idea, experimental techniques, and analysis are presented as well as a historical review of previous experimental attempts. Emphasis is made for the experimental conditions for populating a kinematically isolated tetra-neutron system with very small momentum transfer. The spectral shape is discussed by means of reaction processes and correlations in the final tetra-neutron system with several recent theoretical studies.

会場: コモンルーム (246-248号室) (メイン会場) / via Zoom

イベント公式言語: 英語

Mergers of neutron star-neutron star (or black hole) binaries as r-process sites

2023年1月13日(金) 14:00 - 15:00

和南城 伸也 (Senior Scientist, Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Germany)

The discovery of an electromagnetic counterpart (kilonova) associated with GW170817 confirms that binary neutron star (NS) mergers are at least one of sites of r-process nucleosynthesis. However, there is no observational evidence that black hole (BH)-NS mergers are r-process sites. In this talk, we overview the latest work of nucleosynthesis based on long-term hydrodynamics simulations of NS-NS and BH-NS mergers covering early dynamical and late post-merger mass ejections. We also briefly discuss a possible constraint on nuclear equations of state.

会場: via Zoom / コモンルーム (246-248号室)

イベント公式言語: 英語

Basic of microbial ecology and applicability of your life and research

2023年1月12日(木) 16:00 - 17:00

熊倉 大騎 (北海道大学 大学院生命科学院 生命科学専攻 博士課程)

Microbial ecology is a fascinating field that examines the various environments in which microbes can thrive and their potential applications to human life. In this seminar, I will delve into four main topics:

会場: via Zoom

イベント公式言語: 英語

Searching for high-freqeuncy gravitational waves with axion detectors

2023年1月12日(木) 14:00 - 15:30

ヴァレリー・ドムケ (Senior Faculty, Department of Theoretical Physics, CERN, Switzerland)

Current gravitational wave (GW) experiments cover a large frequency range from nHz to kHz. Beyond that, the regime of high frequency GWs is both extremely challenging challenging, and highly motivated as a unique window to the very early Universe. In this talk I will discuss a proposal for a new type of electromagnetic GW detector which makes use of the observation that GWs generate oscillating electromagnetic effects in the vicinity of external electric and magnetic fields. This is in close analogy to the interaction of the axion with electromagnetic fields. I will discuss how existing bounds from axion searches can be recast for GWs, as well as implications for future axion searches such as the DMRadio program.

会場: コモンルーム 246-248号室 とZoomのハイブリッド開催

イベント公式言語: 英語

第二回 社会課題は数理科学で解決できる!?−企業課題と数理研究をつなぐ−

2023年1月7日(土) 13:00 - 17:00

昨年度に引き続き数理科学研究による社会課題の解決の可能性を探るシンポジウムを開催します。昨年度は、「数理研究の社会実装―課題と克服」というテーマで、企業の課題から抽出された数理課題に取り組む数理科学者の講演会を行い、個々の研究者レベルで興味ある課題についての取り組みが活発になっていることを見ました。今年度は、さらに広い課題で数理科学者と企業での課題を「つなぐ」をテーマにして、企業と共同研究を強く推進されている研究者だけでなく企業の立場から数理科学研究者との連携をなさっている企業側の皆様の活動を紹介し、その活動の成果だけでなく、連携の難しさやその解決のための意見交換を参加者の皆様と共有するパネルセッションを設けたいと考えています。このような活動に興味のある企業研究者や数理科学者の皆様の積極的な参加を心よりお待ちしています。 主催： JST未来社会創造事業「共通基盤」領域 本格研究課題　未来医療を創出する4次元トポロジカルデータ解析数理基盤の開発 共催： 九州大学 マス・フォア・インダストリ研究所 理化学研究所iTHEMS 後援： 株式会社 理研数理，株式会社JSOL， 京都大学 大学院理学研究科 附属サイエンス連携探索センタ−(SACRA) コーディネート： 名古屋大学大学院 理学研究科 生命理学専攻 異分野融合生物学研究室/iBLab 【招待講演】 岡島博司（トヨタ自動車株式会社 先進技術開発カンパニー 主査）“トヨタ自動車に於ける統計数理の取り組みと今後に向けた期待” 杉田有治（理化学研究所 開拓研究本部 主任研究員）“分子動力学ソフトウェアGENESISの開発と「富岳」を用いた創薬・医療応用計算” 藤澤克樹（九州大学マス・フォア・インダストリ研究所　教授）“デジタルツインのための数理・情報技術と産業応用−量子スマート工場の構築に向けて−” 【パネルディスカッション】　 企業活動と数理研究をつなぐことについてうまくいったこと，いかなかったこと，企業側と数理側の立ち位置の違いやお互いが協力関係をどう築いていくのがよいのか，困難とその克服について議論いただきます． パネリスト： 江村克己（日本電気株式会社 シニアアドバイザー/日本経済団体連合会イノベーション委員会企画部会長） 江田哲也（株式会社 理研数理 社長） 高根沢悟（ダイキン工業株式会社 テクノロジー・イノベーションセンター デジタルエンジニアリンググループ グループリーダー） 池田博榮（九州大学マス・フォア・インダストリ研究所 シニアコーディネーター） 樋口博之（富士通株式会社 発見数理プロジェクト・プロジェクトマネージャー/東北大学 数理科学連携研究センター 特任教授） モデレータ： 庄境誠（京都大学オープンイノベーション機構 統括クリエイティブ・マネージャー）

会場: 名古屋大学 野依記念学術交流館とZoomのハイブリッド開催

イベント公式言語: 日本語

A cell membrane model that reproduces cortical flow-driven cell migration and collective movement

2023年1月5日(木) 16:00 - 17:00

佐藤 勝彦 (北海道大学 電子科学研究所 准教授)

Cellular migration is a key component of numerous biological processes, including the morphogenesis of multicellular organisms, wound healing, and cancer metastasis, where cells adhere to each other to form a cluster and collectively migrate. Although the mechanisms controlling single-cell migration are relatively well understood, those underlying multiple-cell migration still remain unclear. A key reason for this knowledge gap is the so-called many-body problem. That is, many forces—including contraction forces from actomyosin networks, hydrostatic pressure from the cytosol, frictional forces from the substrate, and forces from adjacent cells—contribute to cell cluster movement, making it challenging to model, and ultimately elucidate, the final result of these forces. In this talk, I provide a two-dimensional cell membrane model that represents cells on a substrate with polygons and expresses various mechanical forces on the cell surface, keeping these forces balanced at all times by neglecting cell inertia. The model is discrete but equivalent to a continuous model if appropriate replacement rules for cell surface segments are chosen. When cells are given a polarity, expressed by a direction-dependent surface tension reflecting the location dependence of contraction and adhesion on a cell boundary, the cell surface begins to flow from front to rear as a result of force balance. This flow produces unidirectional cell movement, not only for a single cell but also for multiple cells in a cluster, with migration speeds that coincide with analytical results from a continuous model. Further, if the direction of cell polarity is tilted with respect to the cluster center, surface flow induces cell cluster rotation. The reason why this model moves while keeping force balance on cell surface (i.e., under no net forces from outside) is because of the implicit inflow and outflow of cell surface components through the inside of the cell. I provide an analytical formula connecting cell migration speed and turnover rate of cell surface components.

会場: via Zoom

イベント公式言語: 英語