179件のイベント / 2024年
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セミナー
A socio-ecological and genomic approach to mixed-species formation of African forest guenons
2024年4月4日(木) 16:00 - 17:00
北山 遼 (北海道大学 大学院環境科学院 博士課程)
While many animal groups consist of a single species, some species have been observed forming mixed-species groups (MSGs). It is thought that by forming groups with different species, animals may reduce predation risk, improve foraging efficiency, and even gain social and reproductive benefits. Red-tailed monkeys and blue monkeys, African forest guenons (Tribe Cercopithecini), are known to form MSGs in several regions in Africa, despite the large niche overlap. The underlying mechanisms driving the formation of MSGs in red-tailed monkeys and blue monkeys are still unclear. One reason is that previous studies have been limited to behavioral ecological approaches. By combining field observations with genomic analyses in the laboratory, we seek to shed light on the role of genetic factors in mediating interspecies interactions within MSGs. In this talk, I will introduce our studies on genomic introgression and gut microbiome sharing within the mixed-species population of red-tailed monkeys and blue monkeys in the Kalinzu Forest Reserve, Uganda.
会場: via Zoom
イベント公式言語: 英語
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Quantum simulation of QCD matter: from hadronic scattering to gauge field qubit encoding
2024年4月3日(水) 10:00 - 11:00
ティエンイン・リー (Ph.D. Student, Institute of Quantum Matter, South China Normal University, China)
Recently, quantum computing (QC) has become a new method for solving non-perturbative problems in high-energy physics. Compared to traditional Monte Carlo simulations, the QC method does not encounter the sign problem, making it an effective approach for solving dynamical and finite density problems. The first part of this talk focuses on the quantum simulation of the hadronic scattering process, including the initial state parton distribution functions, intermediate state partonic scattering amplitudes, and final state hadronization. The second part of this talk concentrates on the qubit encoding of Hamiltonian formalism in lattice gauge field theory with a Coulomb gauge. As a preliminary attempt, the qubit encoding of (3+1)-dimensional Coulomb gauge QED will be discussed.
会場: via Zoom
イベント公式言語: 英語
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TadaFest 2024: Toward understanding of the Origin of Spacetime
2024年4月2日(火) 14:00 - 18:00
多田 司 (数理創造プログラム 副プログラムディレクター)
Program 14:00-14:05 Welcome address T. Hatsuda (RIKEN iTHEMS) 14:05-15:35 T. Tada (RIKEN iTHEMS) "Toward understanding of the origin of spacetime" (This talk is in English) 15:35-16:00 coffee break 16:00-16:30 Shin Nakamura (Chuo Univ.) "Application of gauge/gravity duality: application to non-equilibrium physics" (This talk is in Japanese) 16:30-17:00 Kinya Oda (Tokyo Woman's Chiristian Univ.) "Gaussian formalism: From Hesenberg's Uncertainty Principle to Time-Boundary Effect and Lorentz-Covariant Complete Basis for Spinors" (This talk is in Japanese) 17:00-17:30 Gen Tatara (RIKEN, CEMS) "Some topics of spintronics" (This talk is in Japanese) 17:30-18:00 Asato Tsuchiya (Shizuoka Univ.) "Recent progress in the studies of the emergence of space-time in the type IIB matrix model" (This talk is in Japanese) 18:15- informal discussion @ Common space on 3F of the main research building
会場: 大河内記念ホール (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
Coarse-graining black holes out of equilibrium with boundary observables on time slice
2024年4月1日(月) 16:00 - 17:30
竹田 大地 (京都大学 素粒子論研究室 博士課程)
In black hole thermodynamics, defining coarse-grained entropy for dynamical black holes has long been a challenge, and various proposals, such as generalized entropy, have been explored. Guided by the AdS/CFT, we introduce a new definition of coarse-grained entropy for a dynamical black hole in Lorentzian Einstein gravity. On each time slice, this entropy is defined as the horizon area of an auxiliary Euclidean black hole that shares the same mass, (angular) momenta, and asymptotic normalizable matter modes with the original Lorentzian solution. The entropy is shown to satisfy a generalized first law within Einstein theory and, through holography, the second law as well. This second law corresponds to the positivity of the relative entropy in the CFT. Furthermore, by applying this thermodynamics to several Vaidya models in AdS and flat spacetime, we discover a connection between the second law and the null energy condition.
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
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A Selective Survey of Ideas, Tools and Results in Constructive QFT II
2024年4月1日(月) 13:00 - 14:30
クリスティ・コウジ・ケリー (数理創造プログラム 基礎科学特別研究員)
In this talk we continue to discuss the constructive programme in rigorous QFT. Our aim is discuss a few points on difficulties in relation to the definition of Euclidean path integrals and the general strategy of constructive field theory from a constructive perspective. This will motivate a discussion of the fundamental results in probability theory which are the main tools for the construction of Euclidean path integral measures. We might also discuss some points in relation to free fields, including in particular difficulties in the characterisation of massless fields.
会場: via Zoom / セミナー室 (359号室)
イベント公式言語: 英語
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京都大学SACRA-理化学研究所iTHEMS 特別講演会「逆撫での力学」
2024年3月28日(木) 13:30 - 16:30
時枝 正 (Professor, Department of Mathematics, Stanford University, USA)
摩擦、滞り、つっかえ、・・・ これらはさまざまな過程のはかどりを死なせてしまう邪魔者として嫌われがち。ところがこの講演では、あまたの実験をその場でおこない、これらが生むちょっと魔法じみた現象をご覧に入れます。そして最大限多様な現象を、最小限のモデルで解明しましょう。実験のいくつかはご自宅でも簡単に「手品」として楽しめるものです。 会場の収容人数の関係上、参加可能定員は約45名となります。定員に達し次第、受付を終了いたします。 プログラム: 13:00:開場・受付開始 13:30〜15:00:講演「逆撫での力学」 15:00〜16:30:継続討論 主催: 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ー(SACRA)学際融合部門 理化学研究所 数理創造プログラム(iTHEMS)
会場: 京都大学東京オフィス 大会議室
イベント公式言語: 日本語
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セミナー
Fast Rotating Neutron Stars: Spectra, Stability and Universal Relations
2024年3月27日(水) 11:00 - 12:30
クリスチャン・クルーガー (Postdoctoral Researcher, University of Tuebingen, Germany)
In this talk, we study rapidly rotating relativistic stars which are present in various astrophysical systems. First, we study their oscillations and instabilities by taking into account the contribution of a dynamic space-time. The study is based on the linearised version of Einstein’s equations and via this approach the oscillation frequencies as well as the critical values for the onset of a secular instability are determined. We show asteroseismological relations for the fundamental eigenfrequency which are crucial for tackling the inverse problem. Further, we provide universal relations that allow to estimate the moment of inertia (and other bulk quantities) from the knowledge of the triple mass, radius and moment of inertia of an associated non-rotating star. The proposed universal relations facilitate computationally cheap EOS inference codes that permit the inclusion of observations of rotating neutron stars. As a demonstration, we deploy them into a recent Bayesian framework for equation of state parameter estimation that is now valid for arbitrary, uniform rotation. The results are important for all stages of a neutron star’s life but particularly interesting in pre- and post-merger cases. This seminar is held by GW-EOS WG in iTHEMS.
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
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セミナー
Arrhythmic activity rhythms in ants
2024年3月26日(火) 16:00 - 17:00
藤岡 春菜 (岡山大学 環境生命自然科学学域 助教)
Most organisms exhibit a periodic activity of about 24 h. This circadian rhythm is considered to be an adaptation to the fluctuations of the environment. In social insects such as honeybees and ants, individual behavior, including activity-rest rhythms, is influenced by interactions within the colony. However, it is challenging to monitor individual activity-rest rhythms in an ant colony due to their large group size and small body size. To address this, we developed an image-based tracking system using 2D barcodes a monomorphic ant and measured the locomotor activities of all colony members under laboratory conditions. Activity-rest rhythms appeared only in isolated ants, not under colony conditions. This suggests that a mixture of social interactions, not light and temperature, induces the loss of activity-rest rhythms. These findings contribute to our understanding of the diverse patterns of circadian activity rhythms in social insects.
会場: via Zoom
イベント公式言語: 英語
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セミナー
Multimessenger probes of superheavy dark matter decay and annihilation
2024年3月26日(火) 10:18 - 11:00
Saikat Das (京都大学 基礎物理学研究所 ポスドク研究員)
We revisit constraints on decaying very heavy dark matter (VHDM) using the latest ultrahigh-energy cosmic-ray (UHECR; E >1e18 eV) data and ultrahigh-energy (UHE) gamma-ray flux upper limits, measured by the Pierre Auger Observatory. We present updated limits on the VHDM lifetime for masses up to ∼ 1e15 GeV, considering decay into quarks, leptons, and massive bosons. In particular, we consider not only the UHECR spectrum but their composition data that favors heavier nuclei. Such a combined analysis improves the limits at <1e12 GeV because VHDM decay does not produce UHECR nuclei. We also show that the constraints from the UHE gamma-ray upper limits are ∼ 10 times more stringent than that obtained from cosmic rays, for all of the Standard Model final states we consider. The latter improves our limits to VHDM lifetime by a factor of two for dark matter mass >1e12 GeV. We also provide constraints using neutrino flux from dark matter decay, including the neutrino-induced cascades. We consider the interaction of UHE neutrinos with the cosmic neutrino background, leading to the attenuation of the extragalactic flux reaching Earth, which improves our analysis to obtain tighter constraints.
会場: via Zoom
イベント公式言語: 英語
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セミナー
The evolution of unusual inheritance and chromosome behaviour in flies and other critters
2024年3月14日(木) 16:00 - 17:00
Laura Ross (Senior Lecturer, Institute of Evolutionary Biology, University of Edinburgh, UK)
Under Mendelian inheritance, individuals receive one set of chromosomes from each of their parents, and transmit one set of these chromosomes at random to their offspring. Yet, in thousands of animals Mendel's laws are broken and the transmission of maternal and paternal alleles becomes unequal. Why such non-Mendelian reproductive systems have evolved repeatedly across the tree of life remains unclear. My lab studies a variety of arthropod species to understand why, when and how the transmission of genes from one generation to the next deviate from Mendel’s laws. We mainly focus on species with Paternal Genome Elimination: Males transmit only those chromosomes they inherited from their mother to their offspring, while paternal chromosomes are excluded from sperm through meiotic drive. I will present recent work aimed at understanding the evolution of this unusual reproductive strategy in a clade of flies. These flies arguably have one of the most bizarre and complex chromosome systems of any insect and we use this complexity to study a range of topics including the evolution of sex chromosomes, germline-restricted chromosomes and sexual conflict.
会場: セミナー室 (359号室) / via Zoom
イベント公式言語: 英語
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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
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セミナー
Brane field theory with higher-form symmetry
2024年3月12日(火) 14:00 - 15:30
川名 清晴 (Research Fellow, Korea Institute for Advanced Study (KIAS), Republic of Korea)
We propose field theory for branes with higher-form symmetry as a generalization of ordinary Landau theory. The field \psi[C_p^{}] becomes a functional of p-dimensional closed brane Cp embedded in a spacetime. As a natural generalization of ordinary field theory, we call this theory brane field theory. In order to construct an action that is invariant under higher-form transformation, we first generalize the concept of “derivative” for higher-dimensional objects. Then, we discuss various fundamental properties of the brane field based on the higher-form invariant action. It is shown that the classical solution exhibits the area law in the unbroken phase of U(1) p-form symmetry, while it indicates a constant behavior in the broken phase for the large volume limit of Cp. In the latter case, the low-energy effective theory is described by the p-form Maxwell theory. If time permits, we also discuss brane-field theories with a discrete higher-form symmetry and show that the low-energy effective theory becomes a BF-type topological field theory, resulting in topological order.
会場: 研究本館 3階 359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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Condensed Matter Physics of QCD 2024
2024年3月11日(月) - 22日(金)
ゴードン・ベイム (Professor Emeritus, University of Illinois, USA)
新田 宗土 (慶応義塾大学 教授)
Mark Alford (Professor, Washington University in St. Louis, USA)
Sanjay Reddy (Professor, University of Washington, USA)
Dam Thanh Son (Professor, The University of Chicago, USA)
Mikhail Stephanov (Professor, The University of Illinois at Chicago (UIC), USA)
福嶋 健二 (東京大学 大学院理学系研究科 物理学専攻 教授)
山本 直希 (慶応義塾大学)
久德 浩太郎 (京都大学 大学院理学研究科 准教授)
林 優依 (京都大学 基礎物理学研究所)
西村 健太郎 (広島大学)
古城 徹 (東北大学)
北沢 正清 (京都大学 基礎物理学研究所)QCD at finite temperature and density is one of the most challenging problems in modern physics, which plays a crucial role to understand the origin and coevolution of the universe and matter. On the one hand, the relativistic heavy-ion collision experiments in the past decades have opened a new and exciting field to explore physical properties of such a QCD matter at high-tempearture. On the other hand, recent astrophysical observations of compact stars (in particular, events involving neutron stars) is becoming another exciting tool to unveil properties of the dense QCD matter. This molecule-type workshop is aimed at bringing together theorists working on QCD at finite-temperature and density, with a particular focus on dense quark-nuclear matter relevant to neutron star physics. We will mainly cover macroscopic properties of the finite-density QCD matter such as the Lee-Yang edge singularity for a QCD critical point, the renewed Fermi liquid theory for quark-nuclear matter, nuclear superfluidity, color superconductivity, quark-hadron continuity, quantum vortex, and transport phenomena including the weak-intearction processes.
会場: via Zoom / 京都大学基礎物理学研究所
イベント公式言語: 英語
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Macroscopic neutrinoless double beta decay: long range quantum coherence
2024年3月6日(水) 15:30 - 17:30
ゴードン・ベイム (Professor Emeritus, University of Illinois, USA)
This talk will introduce the concept of ``macroscopic neutrinoless double beta decay" (MDBD) for Majorana neutrinos. In this process an antineutrino produced by a nucleus undergoing beta decay, $X\to Y + e^- + \bar \nu_e$, is absorbed as a neutrino by another identical $X$ nucleus via the inverse beta decay reaction, $\nu_e + X \to e^-+Y$. The distinct signature of MDBD is that the total kinetic energy of the two electrons equals twice the end-point energy of single beta decay. The amplitude for MDBD, a coherent sum over the contribution of different mass states of the intermediate neutrinos, reflects quantum coherence over macroscopic distances, and is a new macroscopic quantum effect. We discuss the similarities and differences between the MDBD and conventional neutrinoless double beta decay, as well as give estimates of the rates of MDBD and backgrounds.
会場: 研究本館 3階 359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
Do plants have bones? Silica phytoliths and their role and fate in the development of terrestrial plants and human civilizations
2024年3月1日(金) 14:00 - 15:15
Mikhail Blinnikov (Professor, St. Cloud State University, USA)
Silicon is the second most common element in the Earth’s crust. Some families of higher plants evolved mechanisms for soluble silica to be carried by xylem from groundwater and deposited as plant opal in or around plant cells as phytoliths thought to play a role in the structural support and defense against herbivores. While known since the early 19th century, phytoliths remain an intriguing class of microfossils whose formation and role in plants and their preservation in soils and sediments are a subject for a lot of active research. I outline some emerging themes in phytolith analysis including phytoliths’ role in global biogeochemical cycles, plant-herbivore interactions, and their tracing of evolution of cultural plants, especially cereals such as rice (Oryza), wild rice (Zizania), maize (Zea), wheat (Triticum) and millet (Panicum), all relevant to global archaeology. Some emerging research on phytoliths connects their changes in shapes to plant taxonomy of some families such as grasses and opens up avenues for further investigation of their active construction in the cells of some taxa by yet undiscovered genetically mediated mechanisms. New image analysis techniques and some advanced microscopy methods will allow us to further the field of phytolith study using deep machine learning algorithms and true 3D analysis of their shapes, something where contribution from other branches of science are most welcome.
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
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ワークショップ
理化学研究所-奈良女子大学理学部合同 ダイバーシティ推進ワークショップ 2024
2024年2月29日(木) - 3月1日(金)
理化学研究所数理創造プログラム(iTHEMS)と奈良女子大学理学部は、理化学研究所ダイバーシティ推進室の後援を得て女性研究者育成事業を進めている。その一環として、奈良女子大学の学部生・大学院生23名が、理化学研究所和光キャンパスの複数の研究室を訪問し、研究内容について質疑を行うとともに、iTHEMSの研究者とともにワークショップを開催し、学生自らが発表を行う。 主催:理化学研究所数理創造プログラム、奈良女子大学理学部 プログラム: 2月29日(木) 13:30-14:00 開会の挨拶 初田哲男 (C01, 研究本館2F 246-248号室) 14:00-15:30 東原子分子物理研究室 (CPR) (C32, レーザー棟2F中会議室) 15:30-17:00 多感覚統合神経回路理研白眉研究チーム(CBS) (C56, 脳科学池の端棟3F大会議室) 17:00-18:30 数理創造プログラム (iTHEMS) (C01, 研究本館3F) 18:30-21:00 奈良女子大学学生発表会 (C01, 研究本館3F) 3月1日(金) 9:00-10:30 仁科センターRIBF施設 (RNC) (E01, 仁科RIBF棟) 10:30-12:00 佐甲細胞情報研究室 (CPR) (S01, 生物科学棟3F大セミナー室) 12:00-13:00 昼食 (C61, 総合支援施設) 13:00 閉会
会場: via Zoom
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セミナー
Stochastic tunneling in de Sitter spacetime
2024年2月28日(水) 16:00 - 17:30
宮地 大河 (神戸大学 大学院理学研究科 物理学専攻 宇宙論研究室 博士課程)
The formulation of tunneling in real time formalism is discussed. In the case of de Sitter spacetime, there is a method called the stochastic approach, which is known to reproduce the tunneling predicted by Hawking and Moss in the imaginary time formalism. In the case of accelerated expansion of space, the short-wavelength modes are stretched and transformed into long-wavelength modes. In the stochastic approach, such UV-IR transition is incorporated as quantum noise, and the dynamics of the long-wavelength modes are described by stochastic differential equations. In this talk, we construct a Schwinger-Keldysh path integral that reproduces this stochastic differential equation and reformulate the tunneling probability. We also reproduce the Hawking-Moss tunneling probabilities by using the saddle point approximation.
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
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セミナー
Basic experimental considerations for analyzing gene expression
2024年2月28日(水) 13:00 - 14:00
藤 博貴 (理化学研究所 開拓研究本部 (CPR) 岩崎RNAシステム生化学研究室 学振特別研究員PD)
Methods such as RNA-sequencing and ribosome profiling are indispensable tools for the comprehensive elucidation of the mechanisms underlying gene expression. A fundamental aspect that requires meticulous attention in the execution of these experiment is the extraction of intact RNA and Ribosomes. The integrity and purity of the extracted RNA is critical to ensure the accuracy and reliability of the sequencing data. In this seminar, I will introduce the basic but key points of the extraction process.
会場: 研究本館 3階 共有スペース
イベント公式言語: 英語
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Using a trapped ion quantum computer for hamiltonian simulations
2024年2月28日(水) 10:30 - 12:00
リナルディ エンリコ (クオンティニュアム株式会社 Quantum Machine Learning and Algorithms Senior Research Scientist)
Trapped ion quantum computers, like the H-series quantum hardware by Quantinuum, robustly encode quantum information in long lived and precise qubits. However, utilizing the hardware efficiently requires a full-stack workflow from software libraries to hardware compilers. In this talk we introduce the relevant elements of this stack in the context of solving the quantum dynamics of a spin system on H-series hardware: we start from the definition of the Hamiltonian operator in the qubit Hilbert space using the open-source pytket python library and we define the quantum circuits in measurements to run, on a simulator first and on hardware later.
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
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セミナー
Plant hackers: galling insects extend their phenotypes on the trees by novel plant organogenesis
2024年2月27日(火) 16:00 - 17:00
Xin Tong (理化学研究所 環境資源科学研究センター (CSRS) 細胞機能研究チーム 基礎科学特別研究員)
When it comes to plant-insect interactions, insects are generally seen as pests like caterpillars eating vegetables or fruits. However, one group of insects, the galling insects can induce de novo organogenesis on the host plants which are often woody plants. Each galling insect species ‘designs’ its own gall as the extended phenotype which are so-called species-specific gall formation. Different from leaves and roots, galls represent unique plant organs swiftly formed in response to parasitic organisms, observed across diverse plant species. Yet, the precise mechanisms by which normal plant development is interrupted and redirected to form galls by galling organisms remain elusive. During the talk, I will share some discoveries and views related to aphid gall formation on the elm tree, which is the super host plant for more than 30 galling species, and further discussion about why an insect gall is not simple cell mass but well-organized structure, and how we could systematically understand insect gall formation.
会場: 研究本館 3階 359号室とZoomのハイブリッド開催
イベント公式言語: 英語
179件のイベント / 2024年
イベント
カテゴリ
シリーズ
- iTHEMSコロキウム
- MACSコロキウム
- iTHEMSセミナー
- iTHEMS数学セミナー
- Dark Matter WGセミナー
- iTHEMS生物学セミナー
- 理論物理学セミナー
- 情報理論SGセミナー
- Quantum Matterセミナー
- ABBL-iTHEMSジョイントアストロセミナー
- Math-Physセミナー
- Quantum Gravity Gatherings
- RIKEN Quantumセミナー
- Quantum Computation SGセミナー
- Asymptotics in Astrophysics SG Seminar
- GW-EOS WGセミナー
- DEEP-INセミナー
- NEW WGセミナー
- Lab-Theory Standing Talks
- 場の量子論セミナー
- STAMPセミナー
- QuCoInセミナー
- Number Theory Seminar
- 産学連携数理レクチャー
- Berkeley-iTHEMSセミナー
- iTHEMS-仁科センター中間子科学研究室ジョイントセミナー
- RIKEN Quantumレクチャー
- 作用素環論
- iTHEMS集中講義-Evolution of Cooperation
- 公開鍵暗号概論
- 結び目理論
- iTHES理論科学コロキウム
- SUURI-COOLセミナー
- iTHESセミナー