Understanding Biological Clocks Using Methods from Applied Mathematics and Theoretical Physics

2026年4月16日(木) 12:30 - 13:30

黒澤 元 (理化学研究所 数理創造研究センター (iTHEMS) 数理基礎部門 専任研究員)

Imagine that you are in a room with no information about time. The room is located in a cave, where temperature and light intensity remain constant. In such an environment, would you be able to wake up tomorrow or the day after? In fact, most humans can wake up at roughly similar times on successive days. This is because we possess internal daily rhythms, known as circadian rhythms. Biological experiments have shown that such rhythms are not unique to humans, but are shared by many species on Earth. In this talk, I will introduce some open problems related to these daily rhythms, and discuss approaches based on dynamical systems theory and the renormalization group method, from the perspectives of applied mathematics and theoretical physics.

会場: via Zoom / セミナー室 (359号室)

イベント公式言語: 英語

RIKEN Seminar: Formulation of Life Phenomena from Quantum Theory

2026年4月16日(木) 14:00 - 16:05

13:45 Opening 14:00-14:05 Introduction Atsushi Iriki (Teikyo University Advanced Comprehensive Research Organization Division of Artificial Intelligence, RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)) 14:05-14:35 "Interpretation of Life Phenomena Using Quantum Wave Functions and Field Theory" Kazuhiro Sakurada (Keio University Medical School and RIKEN Center for Integrative Medical Sciences (IMS), Predictive Medicine Special Project (PMSP)) 14:35-14:45 Q&A 14:45-15:30 "Bridging neurophysiology and quantum-like cognition" Andrei Khrennikov (Center for Mathematical Modeling in Physics and Cognitive Sciences Linnaeus University) 15:30-15:45 Q&A 15:45-16:00 "Quantum-Like Measurement" Masanao Ozawa (RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS), RIKEN TRIP FQSP, and Nagoya University) 16:00-16:05 Closing Remarks Satoshi Iso (Director, RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)) Host Laboratory: Predictive Medicine Special Project, RIKEN Center for Integrative Medical Sciences (IMS) / RIKEN Center for Interdisciplinary Theoretical and Mathematical Science (iTHEMS) *Registration is required by April 14 via the registration form. Contact: Predictive Medicine Special Project (pmsp-web@ml.riken.jp)

会場: 理化学研究所 和光キャンパス 脳科学池の端研究棟（建物番号C56）3階305

イベント公式言語: 英語

Searching For Anomalies with Foundation Models

2026年4月16日(木) 14:00 - 15:30

Vinicius Massami Mikuni (名古屋大学 素粒子宇宙起源研究所 (KMI))

This is a joint seminar with Institute for Physics of Intelligence (iπ), UTokyo Anomaly detection relaxes the assumptions of how new physics should look and extends the reach of what we can discover. However, interpreting the data and estimating backgrounds remains a challenge. In this new work, we investigate anomalous events selected by the OmniLearned Foundation model across different model sizes, performing a full analysis using CMS Open Data. Surprisingly, models of different sizes, trained on the same data with the same loss functions, select entirely different collisions. In particular, the large OmniLearned model (500M parameters) selects events that are not well described by our background model.

会場: 東京大学 本郷キャンパス 理学部１号館 (メイン会場) / via Zoom

イベント公式言語: 英語

TJR-iTHEMS Joint Seminar: Golden Age of Neutron Stars

2026年4月17日(金) 16:00 - 17:00

ゴードン・ベイム (Professor Emeritus, University of Illinois, USA)

This is a TJR-iTHEMS Joint Seminar supported by ASPIRE Program ABSTRACT Neutron stars were first posited in the early thirties, and discovered as pulsars in the late sixties; however we are only recently beginning to understand the matter they contain. I will describe the ongoing development of a consistent picture of the liquid interiors of neutron stars, now driven by ever increasing observations as well as theoretical advances. These include observations of heavy neutron stars of about 2.0 solar masses and higher; ongoing inferences of masses and radii by the NICER telescope; and observations of binary neutron star mergers, through gravitational waves as well as across the electromagnetic spectrum. Theoretically an understanding is emerging in QCD of how nuclear matter can turn into deconfined quark matter, which I will illustrate with modern quark-hadron crossover equations of state. BRIEF BIO Gordon Baym is a Professor of Physics at the University of Illinois. Educated at Cornell and Harvard, he spent two years at the Niels Bohr Institute. His interests range from matter under extreme conditions to ultracold atomic physics, astrophysics, and nuclear physics. A pioneer in the study of pulsars and neutron stars, he is a member of the U.S. National Academy of Sciences and received the APS Medal for Exceptional Achievement in Research, the Hans Bethe and Lars Onsager Prizes, and the Eugene Feenberg Memorial Medal.

会場: 大阪大学豊中キャンパス H701

イベント公式言語: 英語

iTHEMS × academist オンラインイベント「数理で読み解く科学の世界 2026」

2026年4月18日(土) 10:00 - 15:30

小泉 淳之介 (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)
福島 理 (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)
洪 木子 (理化学研究所 数理創造研究センター (iTHEMS) 数理基礎部門 特別研究員)
大窪 健児 (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)

「数理で読み解く科学の世界」は、2020年より毎年4月に開催しているオンラインイベントです。主催のiTHEMSは、「数学」を共通言語として、物理、生物、宇宙などさまざまな科学分野の横断的な研究をしており、イベントでは、iTHEMS所属の若手研究者4名が最先端の研究について中学生や高校生にもわかるように30分程度の講演を行います。また、一般参加者からの質問やコメントを受け付ける時間も設けています。 詳細、参加お申し込みは、関連リンクをご覧ください。 日時：2026年4月18日（土）10:00〜15:30（開場 9:45） 場所：Web会議サービス「Zoom」（申込者に事前に招待URLをお伝えいたします） 参加費：無料 対象者：中学生・高校生、社会人（どなたでもご参加いただけます） 主催：iTHEMS 共催（企画・運営・宣伝）：アカデミスト株式会社 特別協力：NPO法人 数理の翼 タイムスケジュール： 10:00～　開始の挨拶・イベント概要説明 10:15～　講演「幾何学的に見る整数論の世界」小泉 淳之介 博士 11:15～　講演「対称性がつむぐ量子のふるまい」福島 理 博士 12:10～　昼休み企画 「AI時代の知性と学び　−甘利俊一×磯暁」 出演：甘利 俊一 博士（理研栄誉研究員、帝京大学先端総合研究機構 特任教授）、磯 暁 博士（理研 iTHEMS センター長） 進行：篠崎 菜穂子（フリーアナウンサー） 13:05～　講演「宇宙の始まりとインフレーション理論」洪 木子 博士 14:05～　講演「AIと進化で考える生命のしくみ ― 遺伝子ネットワークから生まれる遺伝の法則 ―」大窪 健児 博士 15:00〜　アフタートーク 15:30　　終了予定

会場: via Zoom

イベント公式言語: 日本語

Analytical parametrization of the primordial power spectrum in effective Loop Quantum Cosmology

2026年4月20日(月) 13:00 - 14:00

Almudena Sánchez Guillén (Ph.D. Student, Institute of Structure of Matter (IEM-CSIC), Spain)

We investigate the imprints on the angular power spectra of cosmological perturbations of a pre-inflationary bounce phase, as described by the hybrid and dressed metric approaches to loop quantum cosmology. For this purpose, we derive a new parametrization of the primordial power spectrum at the end of the inflationary regime. Apart from slow-roll coefficients and cosmological parameters that are present in the standard cosmological scenario without quantum modifications, this parametrization additionally depends only on pre-inflationary physics. More specifically, we find a dependence on the number of e-folds during the bounce epoch and on a characteristic suppression scale which, given the e-folds accumulated during cosmic evolution, is determined by the energy density at the bounce.

会場: via Zoom / セミナー室 (359号室)

イベント公式言語: 英語

Challenges in virology & neurodegeneration: improving experimental procedures and theoretical insights

2026年4月20日(月) 14:00 - 15:00

カトゥリン・ボシゥメン (理化学研究所 数理創造研究センター (iTHEMS) 副センター長)

After repeatedly finding errors in experimental data provided by collaborators, my group developed an online tool (midSIN, https://midsin.roadcake.org/) to improve estimating the concentration of infectious viruses in samples. This led to an unexpected new collaboration with researchers working to measure the concentration of aggregating fibrils in samples from patients suffering from neurodegenerative diseases such as Dementia with Lewy Body and Parkinson's. In the first part of my talk, I will introduce the basics of how infectious virions and aggregating fibril concentrations are measured experimentally, and discuss challenges in tackling these assays' limitations to improve their accuracy and sensitivity. In the second part of my talk, I will discuss the challenges we face in trying to identify the type and minimal number of experimental measurements required to predict the severity and transmission efficacy of diverse influenza viruses collected as part of pandemic surveillance efforts. I hope you will join the talk to learn of these challenges and consider contributing new ideas or approaches to overcome them.

会場: 研究本館 4階 435-437号室とZoomのハイブリッド開催

イベント公式言語: 英語

Quantum generative learning via diffusion

2026年4月21日(火) 10:00 - 11:00

Zhang Bingzhi (PostDoc, University of Southern California, USA)

Deep generative models are key-enabling technology to computer vision, text generation, and large language models. Generative models for quantum data offer a promising route toward learning and preparing complex quantum-state ensembles. In this talk, I will introduce the quantum denoising diffusion probabilistic model (QuDDPM) [1], which adapts the diffusion-model idea to quantum systems through a forward randomization process and a trainable backward denoising dynamics. I will discuss how this framework enables stepwise learning of target quantum state ensembles and demonstrate its capabilities in various learning tasks. I will then present its extension to mixed states to eliminate the need for scrambling [2]. I will conclude with a brief discussion of recent results on scaling laws of quantum information lifetime in monitored quantum dynamics, emphasizing how mid-circuit measurements can maintain information and provide useful intuition for measurement-assisted quantum machine learning.

会場: via Zoom

イベント公式言語: 英語

Quantum Computing of Molecular Properties for Fundamental Physics

2026年4月21日(火) 16:30 - 18:00

プラディヨット・プリタム・サフー (東京大学 大学院理学系研究科 大学院外国人研究生)

This is the self-introduction talk by Pradyot Pritam Sahoo. Pradyot is a Student Trainee 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

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

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

Mathematical Application Research Team Meeting #14

2026年4月24日(金) 14:00 - 15:30

太田 慎一 (大阪大学 理学研究科 教授)

Mathematical Application Research Team is honored to invite Prof. Shin-ichi Ohta from the University of Osaka to this meeting. Everyone is welcome to join the meeting to listen to his seminar. Title: Synthetic and comparison Lorentzian geometry Abstract: In this talk we review recent developments of synthetic geometric approaches to Lorentzian geometry, motivated by the theory of less regular spacetimes in general relativity as well as comparison geometry in the Riemannian setting. Among others, optimal transport theory plays a vital role.

会場: 研究本館 3階 359号室 (メイン会場) / via Zoom

イベント公式言語: 英語

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 TBA (Masato Taki) 16:20–16:40 TBA (Tae-Geun Kim, FudanU) 16:40–17:00 TBA (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

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)

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

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)

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

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

Stochastic Schrödinger Diffusion Models for Pure-State Ensemble Generation

2026年5月14日(木) 14:30 - 15:00

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

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)

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

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