Featured News
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RIKEN Research: Flitting between the wings of a butterfly
Just making small tweaks to certain variables could potentially modify extreme weather events such as sudden downpours, computer simula- tions by two RIKEN researchers have shown. Scientists have long desired to develop ways to control the weather. Research in this area has intensified due to climate change, which is giving rise to more extreme weather events. Present methods for modifying the weather have limited success. Seeding the atmosphere can induce rain, but only when the atmosphere is already in a state where it might rain. Geoen- gineering projects have been envisioned, but they have yet to be conducted due to concerns about unpredicted long-term effects. As a promising approach, Takemasa Miyoshi and Qiwen Sun, both of the RIKEN Center for Computational Science, have looked to chaos theory to assess the possibility of mitigating weather events such as torrential rain by making small changes. Instead of con- sidering the weather system in all its complexity, they focused on a far simpler system—the butterfly attractor. To read more, please see related links.
2022-06-28
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RIKEN Research: Worming out of the black-hole information paradox
RIKEN physicist and two colleagues have found that a wormhole—a theoretical bridge connecting distant regions of the Universe—may help to shed light on the mystery of what happens to information about matter consumed by black holes. Einstein’s theory of general relativity predicts that nothing that falls into a black hole can escape its clutches. But in the 1970s, Stephen Hawking calculated that black holes should emit radiation when quantum mechanics, the theory governing the microscopic realm, is considered. “This is called black hole evaporation because the black hole shrinks, just like an evaporating water droplet,” explains Kanato Goto of the RIKEN Interdisciplinary Theoretical and Mathematical Sciences. To read more, please see related links.
2022-06-28
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RIKEN-Berkeley Center was opened
RIKEN iTHEMS and N3AS Physics Frontier Center have started a joint research center, RIKEN-Berkeley Center (RBC), physically located on the 3rd floor of the physics building in Univ. California, Berkeley. This new Center aims to enhance the collaboration on nuclear astrophysics and quantum information science between the two institutions. On May 27-29, 2022, the first annual meeting of N3AS was held in Berkeley together with their international partners, RIKEN iTHEMS and CNRS Centre Pierre Binetruy. iTHEMS members are encouraged to use RBC as a base to interact with researchers in physics, mathematics, biology and related fields at Berkeley.
2022-06-09
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Ryosuke Iritani was interviewed by The Big Issue of Japan
Ryosuke Iritani (Research Scientist, iTHEMS) is interviewed by The Big Issue Japan, and the latest volume (vol 432) is just published on 1st June. The Big Issue is a magazine dedicated to supporting people in difficult circumstances and helping them achieve self-reliance. Each issue costs 450 yen, out of which 230 yen is the direct income of the street sales staff. The content is about mathematical biology and is accessible for anyone. We hope as many people as possible take it a read and support the people!
2022-06-06
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進化・生態ダイナミクスの共通法則 －生物の個体群変化を物理学的な関係式で記述する－
理化学研究所（理研）生命機能科学研究センター生体非平衡物理学理研白眉研究チームの足立景亮基礎科学特別研究員（数理創造プログラム基礎科学特別研究員）、理研数理創造プログラムの入谷亮介研究員、濱崎立資上級研究員（開拓研究本部濱崎非平衡量子統計力学理研白眉研究チーム理研白眉研究チームリーダー）の研究チームは、情報理論・統計物理学の手法を用いることで、進化・生態系の個体群ダイナミクスを扱う理論モデルにおいて幅広く成り立つ関係式を提案しました。 本研究成果は、進化や生態系における複雑な個体数の時間的変化を統一的枠組みによって理解することにつながると期待できます。 詳細は関連リンクをご覧ください。
2022-06-06
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巨視的な遷移における速度限界の発見 －連続の式に基づく統一的アプローチ－
理化学研究所（理研）開拓研究本部非平衡統計力学理研白眉研究チームの濱崎立資理研白眉研究チームリーダー（数理創造プログラム上級研究員）は、「巨視的な遷移」を伴うような物理的過程において有用となる「速度限界」、すなわち遷移速度に関する不等式を新たに発見しました。 本研究成果は、量子多体系の熱平衡化の時間スケールなどをはじめとする非平衡統計力学へ示唆を与えると同時に、巨視的な量子系の制御など、近年重要となっている量子技術の基礎的な理解に貢献することが期待できます。 続きは関連リンクをご覧ください。
2022-05-09
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トンガ海底火山噴火のラム波を鮮明に可視化 －ひまわり8号が捉えた波の全貌－
理化学研究所（理研）計算科学研究センターデータ同化研究チームの三好建正チームリーダー（開拓研究本部三好予測科学研究室主任研究員、数理創造プログラム副プログラムディレクター）、大塚成徳研究員（開拓研究本部三好予測科学研究室研究員、数理創造プログラム研究員）の研究チームは、気象衛星ひまわり8号の画像を用いて、2022年1月に発生したトンガの海底火山噴火に伴う音波の一種である「ラム波」を鮮明に可視化する手法を独自に開発しました。さらに、この画像からラム波を自動抽出する手法を開発し、到達時刻分布や地上気圧観測との関係を明らかにしました。 本研究成果は、火山噴火などに伴う大気波動やそれに伴う潮位変動の科学的理解と実況監視、観測データと大気・海洋の大規模計算との融合によるシミュレーションの高度化や将来的な予測手法の開発に貢献すると期待できます。 続きは関連リンクをご覧ください。
2022-05-09
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RIKEN Research: Quantum computing and deep learning could help solve the mysteries of quantum gravity
RIKEN physicists have put quantum computing and deep learning through their paces and found that they are powerful tools for gleaning insights into new theories of quantum gravity [1]. They could thus help solve one of the most formidable challenges in modern physics—developing a theory of gravity that jives with quantum physics. When Einstein nutted out his theory of general relativity in 1915, his only tools were pen and paper. The same was true of the pioneers of quantum theory. But the next major breakthrough in theoretical physics could be made with help from emerging technologies such as quantum computers and machine learning, Enrico Rinaldi of RIKEN Theoretical Quantum Physics Laboratory thinks. “I believe these technologies are poised to transform the way we do theoretical physics,” he says. To read more, please visit the related link.
2022-04-25
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iTHEMS x academist online event was held on April 24, 2022
As the alternative for the lectures at RIKEN’s annual open house, iTHEMS held another online lecture event for the general public with the help of Academist Inc., on April 24th, 2022. This year, the lectures were Masaki Taniguchi, Hidetoshi Taya, Akira Harada, Yingying and Euki Yazaki, who all gave splendid public lectures accessible even to junior-high school students. Each lecturer also served as a commentator to another lecture, asking questions on behalf of the audience. During the lunch break, Program Director Hatsuda showed the offices of iTHEMS and around. The event was moderated by Ms. Michibayashi from Academist; Her facilitation with a wit kept the event lively. At one time during the event, more than two hundred audiences participated.
2022-04-25
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iTHEMS Starter Meeting for FY2022 on April 8, 2022
The iTHEMS Starter Meeting for FY 2021 was held over Zoom as past two years’ meeting to kick off its activity for FY 2022. Over seventy iTHEMS members, frequent visitors and colleagues from other institute got together and introduced each other.
2022-04-11
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数理創造プログラム（Interdisciplinary Theoretical and Mathematical Sciences Program, 略称 iTHEMS アイテムズ）は、理論科学・数学・計算科学の研究者が分野の枠を越えて基礎研究を推進する、理化学研究所の新しい国際研究拠点です。iTHEMSでは、「数理」を軸とする分野横断的手法により、宇宙・物質・生命の解明や、社会における基本問題の解決を目指しています。
Upcoming Events
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セミナー 明日開催
Gradient flow exact renormalization group 1
2022年7月5日(火)13:30 - 17:00
鈴木 博 (九州大学 大学院理学研究院 教授)
Wilson’s exact renormalization group (ERG), which tells how a system changes under the scale transformation, provides a fundamental framework to define quantum field theory even beyond the perturbation theory. It has however been known that it is difficult to preserve a manifest gauge symmetry in ERG because of the usage of the momentum cutoff in ERG. Here, we propose a possible modification of ERG, the gradient flow exact renormalization (GFERG), which preserves a manifest gauge symmetry being based on a gauge-covariant diffusion equation. I explain the basic idea and properties of GFERG. If time permits, I want to present a possible application of GFERG to the consideration of the axial anomaly.
会場: via Zoom
イベント公式言語: 英語
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セミナー
Gradient flow exact renormalization group 2
2022年7月6日(水)13:30 - 17:00
鈴木 博 (九州大学 大学院理学研究院 教授)
Wilson’s exact renormalization group (ERG), which tells how a system changes under the scale transformation, provides a fundamental framework to define quantum field theory even beyond the perturbation theory. It has however been known that it is difficult to preserve a manifest gauge symmetry in ERG because of the usage of the momentum cutoff in ERG. Here, we propose a possible modification of ERG, the gradient flow exact renormalization (GFERG), which preserves a manifest gauge symmetry being based on a gauge-covariant diffusion equation. I explain the basic idea and properties of GFERG. If time permits, I want to present a possible application of GFERG to the consideration of the axial anomaly.
会場: via Zoom
イベント公式言語: 英語
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セミナー
Virus vs. Bacteria: Art of the war in the microbial world
2022年7月7日(木)16:00 - 17:00
御手洗 菜美子 (Associate Professor, Niels Bohr Institute, University of Copenhagen, Denmark)
A virulent phage (virus that infects bacteria) infection to a host bacterial cell results in lysis of the cell, where possibly hundreds of phage particles are released after a latency time. The phage pressure is believed to be an important factor to shape the microbial communities and a driving force of their evolution, and yet we are far from having a full picture of their warfare. In this talk, I highlight a few factors that play significant roles in phage-bacteria interactions and their coexistence, such as the effect of herd immunity and the importance of the spatial structure in a few cells scale to the colony scale. *Her talk will be accessible to physicists, mathematicians, and also biologists.
会場: via Zoom
イベント公式言語: 英語
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コロキウム第20回 MACSコロキウム
2022年7月8日(金)15:00 - 18:00
森 哲 (京都大学 大学院理学研究科 生物科学専攻 准教授)
御手洗 菜美子 (Associate Professor, Niels Bohr Institute, University of Copenhagen, Denmark)15:00-16:00 森 哲博士 「餌の毒で身を守るヘビ：２つの毒器官を持つヤマカガシ」 16:15-17:15 御手洗 菜美子博士「いつ誰が「眠る」か？細菌の成長と休眠」 17:15-18:00 継続討論会
会場: via Zoom
イベント公式言語: 日本語
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セミナー
Stem cells determine complexity of hematopoiesis and immunity: A key in maintenance of homeostasis and fighting disease
2022年7月11日(月)10:00 - 11:30
石川 文彦 (理化学研究所 生命医科学研究センター (IMS) ヒト疾患モデル研究チーム チームリーダー)
The hematopoietic system, is a complex organ in which all cells, including white blood cells (also known as leukocytes), red blood cells and platelets originate from the hematopoietic stem cells. White blood cells/leukocytes are critical effectors of immunity. At baseline, we have about 5000-10000/microL circulating white blood cells/leukocytes, composed of more than ten distinct subsets. Among them, the most abundant (50-60%) is the neutrophil, which are capable of preventing bacterial and fungal infection. Others include T lymphocytes which attack tumors and virus-infected cells and B lymphocytes that produce immunoglobulins. Each of the leukocyte subsets have different roles in protecting us from diseases. Defects in white blood cell number or function expose us to risks of infections and tumors. Maintenance of normal homeostasis of these white blood cells is governed by expression levels of approximately 20,000 genes in hematopoietic stem cells. In this presentation, first, I will discuss current understanding of a hierarchical system of stem cells generating many different kinds of leukocytes. Second, I will talk about leukemia, a cancer of white blood cells, in which critical genes are hit by mutations, resulting in a loss or gain of function of those genes in stem cells. Third, I would like to discuss with the iTHEMS scientists potential approaches by which we can collaborate to understand the normal and diseased human blood/immune systems.
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
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セミナー
Adiabatic pumps in quantum spin systems
2022年7月12日(火)16:00 - 17:15
塩崎 謙 (京都大学 基礎物理学研究所 助教)
The Thouless pump is a one-parameter cycle of 1-dimensional gapped quantum systems with U(1) symmetry, which is classified by integers. In this talk, I introduce a generalization of the Thouless pump to quantum spin systems in any dimension with any finite group onsite symmetry. I show a simple model with Z_2 onsite symmetry, and how it is nontrivial via boundary degrees of freedom. Using the framework of the injective matrix product state, one can construct the topological invariant in a way similar to the Berry phase. If time allows, I will briefly introduce a group cohomology model by Roy and Harper for generic space dimensions and discuss its properties.
会場: via Zoom
イベント公式言語: 英語
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セミナーSpeed limits for macroscopic transitions
2022年7月13日(水)13:30 - 15:00
濱崎 立資 (理化学研究所 開拓研究本部 (CPR) 濱崎非平衡量子統計力学理研白眉研究チーム 理研白眉研究チームリーダー)
Speed of state transitions in macroscopic systems is a crucial concept for foundations of nonequilibrium statistical mechanics as well as various applications in quantum technology represented by optimal quantum control. While extensive studies have made efforts to obtain rigorous constraints on dynamical processes since Mandelstam and Tamm, speed limits that provide tight bounds for macroscopic transitions have remained elusive. Here, by employing the local conservation law of probability, the fundamental principle in physics, we develop a general framework for deriving qualitatively tighter speed limits for macroscopic systems than many conventional ones. We show for the first time that the speed of the expectation value of an observable defined on an arbitrary graph, which can describe general many-body systems, is bounded by the “gradient” of the observable, in contrast with conventional speed limits depending on the entire range of the observable. This framework enables us to derive novel quantum speed limits for macroscopic unitary dynamics. Unlike previous bounds, the speed limit decreases when the expectation value of the transition Hamiltonian increases; this intuitively describes a new trade-off relation between time and the quantum phase difference. Our bound is dependent on instantaneous quantum states and thus can achieve the equality condition, which is conceptually distinct from the Lieb-Robinson bound. We also find that, beyond expectation values of macroscopic observables, the speed of macroscopic quantum coherence can be bounded from above by our general approach. The newly obtained bounds are verified in transport phenomena in particle systems and nonequilibrium dynamics in many-body spin systems. We also demonstrate that our strategy can be applied for finding new speed limits for macroscopic transitions in stochastic systems, including quantum ones, where the bounds are expressed by the entropy production rate. Our work elucidates novel speed limits on the basis of local conservation law, providing fundamental limits to various types of nonequilibrium quantum macroscopic phenomena.
会場: コモンルーム 246-248号室 とZoomのハイブリッド開催 (メイン会場) / via Zoom
イベント公式言語: 英語
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セミナー
Superconducting-like heat current: Effective cancellation of current-dissipation trade-off by quantum coherence
2022年7月25日(月)13:30 - 15:00
田島 裕康 (電気通信大学 大学院情報理工学研究科 助教)
Recent developments in statistical mechanics have revealed a tradeoff between heat current and dissipation [1,2]. In various situations, this current-dissipation tradeoff represents a relationship between thermal energy flow and entropy increase, similar to Joule’s law W=RI^2. On the other hand, the coherence effect on the current-dissipation tradeoff has not been thoroughly analyzed. Here, we systematically analyze how coherence affects the current-dissipation tradeoff [3]. The results can be summarized in the following three rules:
会場: via Zoom
イベント公式言語: 英語
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コロキウムFrom the Black Hole Conundrum to the Structure of Quantum Gravity
2022年7月26日(火)15:30 - 17:00
野村 泰紀 (Director, Berkeley Center for Theoretical Physics, University of California, Berkeley, USA)
Having a complete quantum theory of gravity has long been a major goal of theoretical physics. This is because a naive merger of quantum mechanics and general relativity — though it works in certain limited regimes — suffers from major theoretical problems. A particularly acute one arises when one considers the quantum mechanics of black holes: two fundamental principles of modern physics — the conservation of probability in quantum mechanics and the equivalence principle of general relativity — seem to be incompatible with each other. I will explain how recent theoretical progress begins to address this problem and portray the emerging picture of how spacetime and gravity behave at the level of full quantum gravity.
会場: 理化学研究所 和光キャンパス RIBF棟 2階 大会議室 / via Zoom
イベント公式言語: 英語
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ワークショップ
RIKEN iTHEMSのアウトリーチについての研究会 2022
2022年7月29日(金) - 31日(日)
RIKEN iTHEMS では、「数理」を軸とする分野横断的手法により、宇宙・物質・生命の解明や、社会における基本問題の解決を目指しています。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、RIKEN iTHEMS 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うアウトリーチについての研究会を開催しております。本年は「RIKEN iTHEMSのアウトリーチについての研究会2022 ＠神戸&ZOOM」として、7 月29 日(金)-7月31 日(日) にiTHEMS 数理クール神戸において、できるだけ対面で、ズームを併用して開催いたします。
会場: SUURI-COOL (Kobe) / via Zoom
イベント公式言語: 日本語
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ワークショップ
DM3 - Deep insights and Multiple strategies for Deciphering the Mystery of Dark Matter
2022年9月15日(木) - 17日(土)
会場: SUURI-COOL (Kobe) / via Zoom
イベント公式言語: 英語
Opportunities
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コーディネーター募集 (W22037)
締め切り: 2022年8月5日
コーディネーター 1名。国内の複数の研究機関が参画する横断的プロジェクトの運営等に中心的に携わり、研究資金獲得と研究資金管理にも豊富な経験を有する方。
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研究員又は上級研究員募集 (W21319) *理論生物学、数理生物学、あるいは生物物理学
締め切り: ポストが決まり次第
研究員または上級研究員 若干名。iTHEMSでは、理論生物学、数理生物学、あるいは生物物理学における研究員または上級研究員を募集します。iTHEMSの理念のもと、数理科学におけるトップレベルの研究を行うのみならず、数学、物理学、化学、生物学、情報科学、計算科学、社会科学などの異分野間の学際的共同研究をリードすることが期待されています。今回は、生物物理学の分野で高い能力を持つ若手研究者を募集します。
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研究員又は上級研究員募集 (W21320) *純粋数学、応用数学、情報科学などの数理科学分野
締め切り: ポストが決まり次第
研究員または上級研究員 若干名。iTHEMSでは、純粋数学、応用数学、情報科学などの数理科学分野の研究員または上級研究員を募集します。iTHEMSの理念のもと、数理科学におけるトップレベルの研究を行うのみならず、数学、物理学、化学、生物学、情報科学、計算科学、社会科学などの異分野間の学際的共同研究をリードすることが期待されています。今回は、数理科学の分野で高い能力を持つ若手研究者を募集します。
Latest News
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2022-06-30
今週の論文Week 5, June 2022
Title: Role of the effective range in the density-induced BEC-BCS crossover Author: Hiroyuki Tajima, Haozhao Liang arXiv: http://arxiv.org/abs/2206.12599v1
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2022-06-28
リサーチニュース
RIKEN Research: Flitting between the wings of a butterfly
Just making small tweaks to certain variables could potentially modify extreme weather events such as sudden downpours, computer simula- tions by two RIKEN researchers have shown. Scientists have long desired to develop ways to control the weather. Research in this area has intensified due to climate change, which is giving rise to more extreme weather events. Present methods for modifying the weather have limited success. Seeding the atmosphere can induce rain, but only when the atmosphere is already in a state where it might rain. Geoen- gineering projects have been envisioned, but they have yet to be conducted due to concerns about unpredicted long-term effects. As a promising approach, Takemasa Miyoshi and Qiwen Sun, both of the RIKEN Center for Computational Science, have looked to chaos theory to assess the possibility of mitigating weather events such as torrential rain by making small changes. Instead of con- sidering the weather system in all its complexity, they focused on a far simpler system—the butterfly attractor. To read more, please see related links.
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2022-06-28
リサーチニュース
RIKEN Research: Worming out of the black-hole information paradox
RIKEN physicist and two colleagues have found that a wormhole—a theoretical bridge connecting distant regions of the Universe—may help to shed light on the mystery of what happens to information about matter consumed by black holes. Einstein’s theory of general relativity predicts that nothing that falls into a black hole can escape its clutches. But in the 1970s, Stephen Hawking calculated that black holes should emit radiation when quantum mechanics, the theory governing the microscopic realm, is considered. “This is called black hole evaporation because the black hole shrinks, just like an evaporating water droplet,” explains Kanato Goto of the RIKEN Interdisciplinary Theoretical and Mathematical Sciences. To read more, please see related links.