セミナー
1000 イベント
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セミナーAI and Scientific Discovery
2026年6月3日(水) 14:00 - 15:30
Joseph Ledsam (Google Health Lead, Japan, Google Japan)
Artificial intelligence is having a transformative impact on health and scientific discovery. This presentation will trace the evolution from foundational breakthroughs to the sophisticated capabilities of today's large-scale AI models. It will explore how these advanced systems are creating new possibilities across the healthcare landscape, from accelerating therapeutic development to enhancing diagnostic processes and interpreting complex medical data. The session will also take a deeper look at the future possibilities for AI in health and explore the emerging role of agentic AI in scientific discovery. The core theme is the responsible development of AI to create tools that assist scientists, support healthcare professionals, and empower users. Bio: Dr Joseph Ledsam leads Google Health in Japan, where he works across AI research, digital health and health in Google products. He has led research in medical AI, genomics and drug discovery published in journals including Nature, Nature Medicine and Nature Methods. Before moving to Japan he worked as a medical doctor in the UK, and founded the Health Research and Genomics teams in Google DeepMind. He obtained his medical degree from The University of Leeds, UK, and was a research fellow at University College London during his clinical residency.
会場: 研究本館 435-437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
Bootstrapping Cosmological Correlators
2026年5月28日(木) 16:00 - 18:00
Mang Hei Gordon Lee (Post-Doctoral fellow, Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taiwan)
Currently there are hundreds of models describing inflation, a period of accelerated expansion in our universe. Each model lead to different imprints in cosmological observables, and for the purpose of testing the idea of inflation itself, it is essential to understand which predictions are model independent. This lead to the idea of cosmological bootstrap, a set of constraints from physical principles and symmetries alone. In this talk I will give an overview on the cosmological bootstrap program. I will first explain how locality, unitarity and symmetry can constrain the kinematics of cosmological correlators. I will then talk about some recent progress on constructing positivity bounds on cosmology, which places constraints on the interactions of fields in inflation.
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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セミナーIntroduction to categorification and link homology
2026年5月28日(木) 14:00 - 15:30
Mikhail Khovanov (Professor, Department of Mathematics, Johns Hopkins University, USA)
Quantum link invariants relate topology in 3 dimensions to mathematical physics and representation theory. They admit liftings to 4-dimensional structures, known as link homology. We will explain how the skein relations for quantum invariants turn into homological structures at this higher level and how semisimple representation theory turns into non-semisimple representations and homological algebra upon categorification.
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
Singularities of differentiable maps and Thom polynomials
2026年5月22日(金) 15:00 - 17:30
田邊 真郷 (理化学研究所 数理創造研究センター (iTHEMS) 数理基礎部門 基礎科学特別研究員)
Singularities are locations where something is exceptional. In particular, singularities of differentiable maps are mathematical concepts corresponding to stationary points of functions and apparent contours of surfaces under projection onto the retina. These are unavoidable in general, but important to study the shape of spaces and behavior of maps. The theory for them was initiated by R. Thom in 1950's, and have been deeply studied by many researchers.
会場: 理化学研究所 和光キャンパス (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
Stochastic Thermodynamics: noise and energetics of nanoscale systems
2026年5月21日(木) 13:00 - 14:00
Jean-Charles Delvenne (Professor, Applied Mathematics, Université Catholique de Louvain, Belgium)
Stochastic thermodynamics, initiated three decades ago, aims at quantifying the fluctuations of physical observables in relation with thermodynamic quantities (such as heat or entropy production). A typical result is the Thermodynamic Uncertainty Relation, which states that a high entropy production is required to obtain a favorable noise-to-signal ratio for some observables (such as displacement of a molecular motor) in stationary out-of-equilibrium systems. It is especially relevant for nanoscale systems, where the fluctuations cannot be neglected. This includes biological systems (e.g. biological motors such as kinesin along a microtubule), electronic systems (transistor-based memories), chemical reactions, etc. The talk will be both a tutorial on some basic results or applications, and a presentation of some recent results and perspectives.
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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セミナーPositivity constraints for the gravitational path integral
2026年5月21日(木) 10:00 - 11:50
ガブリエル・ディウバルド (理化学研究所 数理創造研究センター (iTHEMS) 国内外連携・人材育成部門 理研バークレーセンター 特別研究員)
For a quantum theory of gravity to have a well-defined Hilbert space, the inner product between different states of open and closed universes must be positive semi-definite. Positivity however is not manifest in the low-energy effective theory and in fact imposes nontrivial constraints on the theory. Working in the Gravitational Path Integral (GPI) approach, we derive the general set of positivity constraints on the closed and open universe Hilbert spaces. In the case of AdS gravity, open universe positivity in principle follows from CFT unitarity, however the holographic description of closed universes remains unclear. Strikingly, we exhibit positivity of closed universes across many theories and prove that open positivity implies closed positivity, showing that the CFT 'knows' about the closed universe hilbert space. We then analyze positivity constraints on gravitational theories coupled to axions. We present a method to compute off-shell axion wormholes in AdS and flat space which we use to show that positivity is violated if the axion shift symmetry is exact. In low-energy EFTs where these wormholes are perturbatively stable, to restore positivity the wormhole must have a non-perturbative instability due to instantons that breaks the shift symmetry. Positivity then leads to a proof of a sharp version of the Axion Weak Gravity Conjecture A-WGC, including precise numerical constants. For the QCD axion this provides a bound on the axion decay constant which has phenomenological and experimental consequences for axion searches. In string theory, positivity gives a bound on the coupling between the axion and the dilaton in the low energy effective action.
会場: via Zoom
イベント公式言語: 英語
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セミナー
Realizing two-dimensional discrete time crystals on a digital quantum computer
2026年5月19日(火) 15:00 - 16:30
新城 一矢 (理化学研究所 創発物性科学研究センター (CEMS) 計算物性物理研究室 研究員)
This work was featured in a RIKEN press release. For details, please see the related link.
会場: via Zoom (メイン会場) / セミナー室 (359号室)
イベント公式言語: 英語
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セミナーIntroduction to quantum resource theories (3)
2026年5月15日(金) 9:00 - 17:00
高木 隆司 (東京大学 大学院総合文化研究科 准教授)
[Registration Closed] Due to high demand and venue capacity limits, registration for this course is now closed as of April 25. If you wish to be placed on a waiting list in case of cancellations, please contact us via the inquiry form at the bottom of this page. One of the central goals of quantum information theory is to quantitatively clarify the relationship between the performance of quantum information processing and the valuable quantum features that underlie it. In this lecture, we will discuss quantum resource theories, a framework that provides a useful approach to this question. By presenting concrete examples—starting with entanglement theory, the most representative resource theory—as well as recent research results, we will see how perspectives and tools from information theory enable the quantification of quantum resources and the characterization of their convertibility. Beyond entanglement theory, we plan to discuss other key settings such as quantum thermodynamics, resource theory of asymmetry, and quantum magic—relevant resource in fault-tolerant quantum compuation. The overall aim of this lecture is to provide new analytical viewpoints that can be applied to a wide range of systems and quantum information processing tasks. While we do not plan to change the overall start and end times for each day, the detailed lecture schedule is subject to change. The intensive course will be held over three days. Please register for the course using the form. The registration deadline is May 7 (Thu). Please note that the registration form is the same for all three days, so you only need to register once. The 3rd day: May 15 (Fri) 9:00–10:30 Lecture 7 10:30–11:00 Coffee break 11:00–12:30 Lecture 8 12:30-13:30 Lunch time 13:30-15:00 Free discussion/Summary of the lectures 15:00-15:30 Coffee break 15:30-17:00 Lecture 9/Seminar This event is in-person only.
会場: 研究本館 4階 435-437号室
イベント公式言語: 英語
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セミナーStochastic Schrödinger Diffusion Models for Pure-State Ensemble Generation
2026年5月14日(木) 14:30 - 15:30
ジアン・シュウ (理化学研究所 数理創造研究センター (iTHEMS) 数理展開部門 量子数理科学チーム 特別研究員)
In quantum machine learning (QML), classical data are often encoded as quantum pure states and processed directly as quantum representations, motivating \emph{representation-level generative modeling} that samples new quantum states from an underlying pure-state ensemble rather than re-preparing them from perturbed classical inputs. However, extending \emph{score-based} diffusion models with well-defined reverse-time samplers to quantum pure-state ensembles remains challenging, due to the non-Euclidean geometry of the complex projective space $\mathbb{CP}^{d-1}$ and the intractability of transition densities. We propose \emph{Stochastic Schr\"odinger Diffusion Models} (SSDMs), an intrinsic score-based generative framework on $\mathbb{CP}^{d-1}$ endowed with the Fubini--Study (FS) metric. SSDMs formulate a forward Riemannian diffusion with a stochastic Schr\"odinger equation (SSE) realization, and derive reverse-time dynamics driven by the Riemannian score $\nabla_{\mathrm{FS}} \log p_t$. To enable training without analytic transition densities, we introduce a local-time objective based on a local Euclidean Ornstein--Uhlenbeck approximation in FS normal coordinates, yielding an analytic teacher score mapped back to the manifold. Experiments show that SSDMs faithfully capture target pure-state ensemble statistics, including observable moments, overlap-kernel MMD, and entanglement measures, and that SSDM-generated quantum representations improve downstream QML generalization via representation-level data augmentation.
会場: セミナー室 (359号室) 3階 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
From Birkhoff's Polytope to Petz Recovery: Unistochastic Matrices, Quantum Channels, and Approximate Markov Chains
2026年5月13日(水) 13:30 - 15:00
Claude Gravel (Assistant Professor, Department of Computer Science, Toronto Metropolitan University, Canada)
A doubly stochastic matrix is unistochastic if its entries correspond to the squared moduli of a unitary matrix. Determining which n × n doubly stochastic matrices admit such a representation remains an open problem at the intersection of convex geometry, combinatorics, and quantum information. For 3 × 3 matrices, elegant triangle inequalities provide a complete characterization: the unistochastic set occupies approximately 75% of the Birkhoff polytope and exhibits deltoid cross-sections. For n ≥ 4, the characterization problem remains unresolved and is influenced in unexpected ways by the prime factorization of n via the defect of the Fourier matrix. This presentation surveys these results and then establishes a connection to a second, seemingly unrelated question: given a tripartite quantum state with small conditional mutual information, to what extent can one subsystem be recovered from the others? The Petz recovery map and its rotated variants offer a universal solution. These two topics are linked through coherification, which concerns when a classical stochastic process can be elevated to coherent quantum dynamics, and through the conditional mutual information as a continuous measure of non-unistochasticity. The talk concludes with open problems at this interface, including the star-shapedness conjecture for n = 4 and the pursuit of tighter recovery bounds.
会場: セミナー室 (359号室) 3階 359号室
イベント公式言語: 英語
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セミナー
Introduction to quantum resource theories (2)
2026年5月12日(火) 9:00 - 17:00
高木 隆司 (東京大学 大学院総合文化研究科 准教授)
[Registration Closed] Due to high demand and venue capacity limits, registration for this course is now closed as of April 25. If you wish to be placed on a waiting list in case of cancellations, please contact us via the inquiry form at the bottom of this page. One of the central goals of quantum information theory is to quantitatively clarify the relationship between the performance of quantum information processing and the valuable quantum features that underlie it. In this lecture, we will discuss quantum resource theories, a framework that provides a useful approach to this question. By presenting concrete examples—starting with entanglement theory, the most representative resource theory—as well as recent research results, we will see how perspectives and tools from information theory enable the quantification of quantum resources and the characterization of their convertibility. Beyond entanglement theory, we plan to discuss other key settings such as quantum thermodynamics, resource theory of asymmetry, and quantum magic—relevant resource in fault-tolerant quantum compuation. The overall aim of this lecture is to provide new analytical viewpoints that can be applied to a wide range of systems and quantum information processing tasks. While we do not plan to change the overall start and end times for each day, the detailed lecture schedule is subject to change. The intensive course will be held over three days. Please register for the course using the form. The registration deadline is May 7 (Thu). Please note that the registration form is the same for all three days, so you only need to register once. The 2nd day: May 12 (Tue) 9:00–10:30 Lecture 3 10:30–11:00 Coffee break 11:00–12:30 Lecture 4 12:30-13:30 Lunch time 13:30-15:00 Lecture 5 15:00-15:30 Coffee break 15:30-17:00 Lecture 6 This event is in-person only.
会場: 研究本館 4階 435-437号室
イベント公式言語: 英語
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セミナー
Introduction to quantum resource theories (1)
2026年5月11日(月) 13:30 - 17:00
高木 隆司 (東京大学 大学院総合文化研究科 准教授)
[Registration Closed] Due to high demand and venue capacity limits, registration for this course is now closed as of April 25. If you wish to be placed on a waiting list in case of cancellations, please contact us via the inquiry form at the bottom of this page. One of the central goals of quantum information theory is to quantitatively clarify the relationship between the performance of quantum information processing and the valuable quantum features that underlie it. In this lecture, we will discuss quantum resource theories, a framework that provides a useful approach to this question. By presenting concrete examples—starting with entanglement theory, the most representative resource theory—as well as recent research results, we will see how perspectives and tools from information theory enable the quantification of quantum resources and the characterization of their convertibility. Beyond entanglement theory, we plan to discuss other key settings such as quantum thermodynamics, resource theory of asymmetry, and quantum magic—relevant resource in fault-tolerant quantum compuation. The overall aim of this lecture is to provide new analytical viewpoints that can be applied to a wide range of systems and quantum information processing tasks. While we do not plan to change the overall start and end times for each day, the detailed lecture schedule is subject to change. The intensive course will be held over three days. Please register for the course using the form. The registration deadline is May 7 (Thu). Please note that the registration form is the same for all three days, so you only need to register once. The 1st day: May 11 (Mon) 13:30-15:00 Lecture 1 15:00-15:30 Coffee break 15:30-17:00 Lecture 2 This event is in-person only.
会場: 研究本館 4階 435-437号室
イベント公式言語: 英語
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セミナー 明日開催Six operations in differential topology
2026年5月8日(金) 15:00 - 17:00
前川 拓海 (理化学研究所 数理創造研究センター (iTHEMS) 数理基礎部門 基礎科学特別研究員)
The formalism of six operations, pioneered by Grothendieck and Verdier, serves as a unifying framework for studying cohomological phenomena. This language realizes Poincaré-type duality and transfer maps as certain adjunctions between stable $\infty$-categories of sheaves. In this talk, we highlight the theory of six operations in topology and apply it to provide an intrinsic version of the Pontryagin-Thom construction. We then discuss the intrinsic construction of invariants coming from Seiberg-Witten theory, which is based on the speaker's previous work.
会場: via Zoom
イベント公式言語: 英語
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セミナー
Building autonomous AI physicists for frontier physics research
2026年4月30日(木) 15:00 - 16:00
Tingjia Miao (Ph.D. Student, School of Artificial Intelligence, Shanghai Jiao Tong University, China)
Advances in LLMs have led to agents with knowledge and operational capabilities comparable to human scientists, suggesting potential to assist, accelerate, and automate research. Physics, especially theoretical and computational physics, which requires integrating analytical reasoning, code-based computation, and profound domain expertise, is well suited for verifying the end-to-end research capabilities of AI scientists. Accordingly, we construct a general-purpose AI physicist PhysMaster, equipped with a layered academic knowledge base, adapted to the agent skill ecosystem, and adopting an adaptive exploration strategy that balances efficiency and exploration, enabling robust performance in ultra-long-horizon tasks; PhysMaster has been open-sourced. Meanwhile, we introduce PRL-Bench (Physics Research by LLMs), a benchmark with 100 tasks adapted from recent Physical Review Letters papers, covering astrophysics, condensed matter physics, high-energy physics, quantum information, and statistical physics. Evaluation across frontier models shows that failures are dominated by conceptual and formulaic errors, and that exploration and derivations remain unstable over long horizons. In addition, we develop domain-specialized AI scientists, including LQCD Master, which integrates Lattice QCD workflows and expert skills, enabling automated generation and submission of lattice computation scripts from concise physics goals.
会場: via Zoom
イベント公式言語: 英語
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セミナー
Uniform Matrix Product States for Hamiltonian Lattice Gauge Theories: Methods and Applications
2026年4月28日(火) 16:00 - 17:30
藤倉 浩平 (京都大学 基礎物理学研究所 基研特任助教)
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
DEEP-IN WG Sarter Meeting 2026
2026年4月27日(月) 15:30 - 17:00
Tae-Geun Kim (Postdoc, Fudan University, China)
Yang-Yang Tan (東京大学 博士研究員)
瀧 雅人 (立教大学 大学院人工知能科学研究科 准教授)15:30–16:00 NOW&NEXT of DEEP-IN WG (Lingxiao Wang) Self-Introduction of Members 16:00–16:20 AI Team and DEEP-IN (Masato Taki) 16:20–16:40 Inverse Problems in HEP (Tae-Geun Kim, FudanU) 16:40–17:00 Inverse Modeling Distributions (Yang-yang Tan, UTokyo)
会場: セミナー室 (359号室) 3階 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
Cooking up holographic black holes
2026年4月27日(月) 13:30 - 15:00
竹田 大地 (理化学研究所 数理創造研究センター (iTHEMS) 数理基礎部門 基礎科学特別研究員)
I have recently been investigating holography for open systems and have developed a method to compute correlation functions of a CFT governed by the Lindblad equation from its gravitational dual. In an open system, the state of the subsystem of interest cannot remain pure, and one naively expects its entropy to grow over time. It is then natural to expect that this thermalization process is accompanied, on the gravity side, by black hole formation. In this talk, after giving an overview of holography for open systems, I will present a numerical nonperturbative analysis of the dynamics of JT gravity coupled to a scalar field, and show that black holes indeed form in this setup.
会場: via Zoom / セミナー室 (359号室) 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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セミナー
Cautionary tales in data analysis from gravitational-wave astronomy
2026年4月23日(木) 13:00 - 14:00
キップ・カンノン (東京大学 ビッグバン宇宙国際センター (RESCEU) 教授)
We'll look at signal detection in noisy data, and at Bayesian inference in astrophysical inverse problems. We'll look at the form these problems take in the context of gravitational-wave astronomy, but we'll focus on where attempts at solutions have gone wrong. The mistakes we make transcend disciplines, and hopefully by shining light on them others can be helped to avoid making them as well.
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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セミナー
The math that shows a perfect democracy is impossible
2026年4月23日(木) 10:30 - 11:30
ブライアン・アンドリュー・ミンツ (理化学研究所 数理創造研究センター (iTHEMS) 数理展開部門 数理社会科学チーム 特別研究員)
Groups need to make decisions, and there are a wide variety of ways this can be done, each maximizing different notions of fairness. Social Choice Theory provides a mathematical framework to investigate these possibilities rigorously. Infamous for its many impossibility results, this topic reveals some fundamental limits to democracy. Beyond this, we'll discuss potential resolutions to these problems, as well as their real world implications.
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
Seeing Photons, from Einstein to Bohr to Hanbury Brown-Twiss and related Hong-Ou-Mandel Interference Phenomena
2026年4月22日(水) 15:00 - 16:30
ゴードン・ベイム (Professor Emeritus, University of Illinois, USA)
Why do we believe that the electromagnetic field is quantized, and photons exist? This talk will focus on two ways that the quantization of the electromagnetic field manifests itself in interference experiments. Bohr, who initially doubted photons after Einstein's initial proposal of the photon to explain the photoeffect, eventually proposed a thought experiment showing that the consistency of elementary quantum mechanics at the level of two slit diffraction requires the quantization of the electromagnetic field. In addition, as I will argue, both Hanbury Brown-Twiss interferometry and the closely related Hong-Ou-Mandel effect provide yet another way to see that the electromagnetic field must be quantized.
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
1000 イベント