34件のイベント / 2025年
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セミナー
Genome and Sex Chromosome Analyses of Japanese Frogs Carrying Both XY and ZW Chromosomes Within the Same Species
2025年2月27日(木) 16:00 - 17:00
桂 有加子 (京都大学 京都大学ヒト行動進化研究センター 助教)
The evolution of sex chromosomes, particularly sex chromosome turnover, is a complex and fascinating topic in genetics and evolutionary biology. Sex chromosome turnover refers to the process in which the sex chromosome system changes from XY to ZW (or vice versa), or in which sex chromosomes with different evolutionary origins emerge within the same system (e.g., from one XY system to another XY system). To study sex chromosome turnover, we focus on the Japanese frog (Glandirana rugosa), which possesses both XY and ZW sex chromosomes within the same species, and investigate the molecular mechanisms behind the turnover in the frog (Review: Hayashi et al. JB 2024). Previously, we sequenced the nuclear genome of the ZZ frog (Katsura et al. LSA 2021) and identified sex-linked genes in two populations of the XY and ZW frogs (Miura et al. Mol Ecol 2022). It has been suggested that sex chromosomes originating from at least three different chromosomal lineages have independently emerged within this species. The frogs have a total of 13 chromosomes, and in two populations (Tokai/Eastern Central Japan and Hokuriku-Tohoku/North-Western Japan), chromosome 7 has morphologically differentiated into both ZW and XY chromosomes. However, in other populations, sex chromosomes do not show any morphological differentiation. In this seminar, I introduce the background of our sex chromosome study and present the results of sequence comparisons of morphologically differentiated XY and ZW chromosomes, as well as findings from our analyses of populations, genome, and transcriptome.
会場: 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
Quantum-Centric Supercomputing Software
2025年2月26日(水) 13:00 - 14:00
Hanhee Paik (IBM Quantum Head of IBM Quantum Japan)
A quantum-centric supercomputer represents the next generation of computing, combining a quantum computer with a classical supercomputer. It leverages error mitigation and error correction techniques to deliver results within practical timeframes. When fully developed, this system relies on advanced middleware to seamlessly integrate quantum circuits with classical computing resources. In this presentation, we will introduce IBM Quantum’s middleware for quantum-centric supercomputers, highlighting collaborative projects with our research partners.
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
Exploiting hidden low-rank structures in quantum field theories
2025年2月24日(月) 13:00 - 14:30
Hiroshi Shinaoka (埼玉大学)
Tensor networks are a powerful tool for compressing wave functions and density matrices of quantum systems in physics. Recent developments have shown that tensor network techniques can efficiently compress many functions beyond these traditional objects. Notable examples include the solutions to turbulence in Navier–Stokes equations [1] and the computation of Feynman diagrams [2,3]. These advancements have heralded a new era in the use of tensor networks for expediting the resolution of various complex equations in physics. This talk will provide an overview of our work utilizing tensor networks for computations based on quantum field theories. First, we will introduce the Quantics/quantized Tensor Train (QTT) representation [3,4] for compressing the space-time dependence of correlation functions in quantum systems [5], leveraging inherent length-scale separation for efficient representation. Second, we will present a robust tool named "Quantics Tensor Cross Interpolation" [6], which learns a quantics low-rank representation of a given function. Applications include the computation of Brillouin zone integrals [6] and integration of complex self-energy Feynman diagrams for multiorbital electron-phonon impurity models [7]. Finally, we will introduce new algorithms [8] and open-source libraries [9] for tensor cross interpolation.
会場: via Zoom / Hong Kong University Science and Technology
イベント公式言語: 英語
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セミナー
Ubiquity of geometric Brascamp--Lieb data
2025年2月21日(金) 15:00 - 17:00
辻 寛 (埼玉大学 大学院理工学研究科 日本学術振興会 特別研究員 PD)
This talk is based on a joint work with Neal Bez (Nagoya university) and Anthony Gauvan (Saitama university). The Brascamp--Lieb inequality is a futher general inequality involving some data (we call it the Brascamp--Lieb datum), which has been studied in harmonic analysis and convex geometry. For instance, the Hölder inequality and the Young convolution inequality are particular cases. In this talk, we have an interest in geometric Brascamp--Lieb data, which are specific data satisfying nice properties, for which the best constant of the Brascamp--Lieb inequality is well-understood. Our goal in this talk is to show that geomtric Brascamp--Lieb data are dense in general Brascamp--Lieb data in certain sence. Our result substantially follows from the work by Garg, Gurvits, Oliveira and Wigderson.
会場: 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
Exploring the evolutionary fate of a mutualistic community using automated microbial culture system
2025年2月20日(木) 16:00 - 17:00
砂川 純也 (北海道大学 大学院生命科学院 生命科学専攻 博士課程)
Microbes are ubiquitous around the world, forming systems where they interact through competition or cooperation. Especially in the form of cooperation, exchange of essential metabolites, known as metabolic cross-feeding, plays a fundamental role in the assembly of microbial communities. An extreme case of metabolic cross-feeding is an obligate mutualism, where one organism can only grow with the help of a partner supplying metabolites (e.g., amino acid). When they face environmental stresses such as antibiotics, it is unclear whether the benefit that causes the formation of obligate ecological mutualism may benefit (or cost) the members to increases (inhibits) resistance through interactions at the evolutionary scale. Another fascinating question is whether an additional benefit (e.g., an enzyme that helps the community persistence against environmental change) will select the community to increase the resistance. Here, I will report my ongoing research progress of obligate cross-feedings involving β-lactamase and discuss the conditions where the benefit can overcome the cost of the obligate interaction. I have started to address this issue by conducting laboratory evolution experiments with an automated culture system which can automatically adjust the strength of the stress (i.e., concentration of the antibiotics), so that the focal microbes have to get evolved. I will also share my story about building this automated culture system.
会場: 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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How to define a Majorana fermion?
2025年2月20日(木) 13:00 - 14:30
藤川 和男 (東京大学 名誉教授)
It is fundamental in particle physics if the neutrino is a Dirac fermion or a Majorana fermion, and the seesaw model gives naturally a Majorana neutrino in an extension of the Standard Model. However, the commonly used chirality changing pseudo−Csymmetry ν˜CL=C¯νLT of a chiral fermion is not defined in Lagrangian field theory. Precisely speaking, the neutrinoless double beta decay is not described by the pseudo-C symmetry. The Majorana neutrino obtained after a Bogoliubov-type canonical transformation, which is the one originally defined by Majorana using a Dirac-type fermion, describes consistently all the properties expected for the Majorana neutrino. Physical implication of this fact is briefly discussed.
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
The Topology, Geometry and Physics of non-Hausdorff manifolds
2025年2月19日(水) 15:00 - 17:00
O'Connell David (沖縄科学技術大学院大学 (OIST) 博士課程)
Non-Hausdorff manifolds are manifolds containing "doubled points" that cannot be separated by disjoint open sets. In this talk we will survey some mathematical and physical results surrounding these unusual spaces. As a theme, we will start with their fundamental description as a topological space, and slowly add in more and more structure of interest until we can meaningfully phrase questions of physics. On the mathematical side, we will see descriptions of non- Hausdorff manifolds as colimits of ordinary manifolds, which allows us to describe their geometric features without appealing to arbitrarily- existent partitions of unity. On the physical side, we will consider the inclusion of non-Hausdorff manifolds in a naïve 2d Lorentzian path integral for gravity, and (time permitting) explain how construct quantum fields on a non-Hausdorff background. Ultimately, we will see that these latter two arguments suggest that non-Hausdorff manifolds may be more appropriate than the standard "Trousers space" for the modelling of topology change in Lorentzian signature.
会場: 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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MACS10周年記念コロキウム・2024年度MACS成果報告会
2025年2月19日(水) 14:45 - 18:30
國府 寛司 (京都大学 理事)
高橋 淑子 (京都大学 大学院理学研究科 生物科学専攻 教授)14:45-15:00 ティータイムディスカッション [15:00-16:30 第1部 MACS10周年記念コロキウム] 15:05-15:05 はじめに(佐々真一 SACRA学際融合部門長) 15:05-15:30 講演1「MACS はどのように始まったか?」國府寛司 博士 (数学・数理解析専攻 教授) 2016年5月のキックオフシンポジウムから始まったMACSが2025年度で10年目を迎えるという時期にあたり,その立ち上げの時のことを振り返ってお話したい.特に,10年前にどのような人々がどのようなことを考えて,それがMACSプログラムに至ったのか,また当初MACSでやりたいと思っていたができなかったことなどを思い出し,この10年のMACSの歩みや,MACSとその後の京大理学の諸活動との関わりなどについて,いくつか取り上げてお話してみたい. 15:30-15:55 講演2「MACSから生まれた躍動感」高橋淑子 博士 (生物科学専攻 教授) 「MACS」は語呂がよかったせいか多くの人に覚えていただき、「名付け親」として嬉しい限りです。私はベタベタの実験発生生物学者であり数学とは縁遠かったのですが、なぜかMACSには初めから首を突っ込む形となり、以来、10年間にわたりSGを企画しました。「本物(トリ胚)をみて数理を考える」という共通テーマのもと、物理・数学の院生や学部生たちが数式を議論し、顕微鏡をのぞいて生(なま)のトリ胚を観る姿に心躍りました。当時ハーバード大から出た「腸ルーピング」論文は、実験生物―物理―数理の融合研究で世の中を驚愕させましたが、「ハーバードでできることが京大理学でできないはずがない」を合い言葉に、新しい挑戦に胸躍る10年間でした。 15:55-16:20 質疑応答 16:20-16:30 休憩 [16:30-18:30 第2部 2024年度 MACS 成果報告会] 16:30-17:30 各スタディグルーブ フラッシュトーク 17:30-18:30 参加学生によるポスター発表
会場: 京都大学 理学研究科セミナーハウス(建物配置図(北部構内)【10】の建物)
イベント公式言語: 日本語
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セミナー
New topological quantum order in 2D lattices from non-invertible symmetries
2025年2月18日(火) 15:00 - 16:00
Ayan Mukhopadhyay (Associate Professor, Valparaiso University, Chile)
I will introduce an exactly solvable 2D lattice model which reveals a large number of distinct topological phases with non-invertible (generalized) symmetries. In all these topological phases, which have topological ground state degeneracy, a commutative stabilizer monoid of Hermitian operators leave the ground state invariant and can also distinguish *all* local excitations, (These symmetries are indeed symmetry operations.) There exists novel confined fractonic excitations which change the nature of deconfined excitatons profoundly. The fusion rules form an associative but noncommutative. non-Abelian and non-unital category, and are distinct for each of these phases. A class of these phases are adiabatically connected to a limit which can be described in terms of generalized free field theories. I will describe systematic ways to construct such phases. I will also discuss phases which do not have generalized free field limits. These phases have novel forms of non-local entanglement as many of them share the same topological entanglement entropy. They also violate the entanglement bootstrap axioms. When the phases do not have a generalized free field limit, the violation of the entanglement bootstrap axioms can happen for arbitrary large subregions signifying new forms of long-range entanglement.
会場: 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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ワークショップ
Theories of Astrophysical Big Bangs 2025
2025年2月17日(月) - 19日(水)
We are pleased to announce an international workshop on theories of Astrophysical Big Bangs. The main topics of the workshop are listed below, although the topics are not limited to these areas. We aim to cover a broad range of astrophysical research concerning various types of cosmic explosions and compact objects. Neutron Stars Neutron Star Mergers Gravitational Waves Gamma-Ray Bursts Supernovae Supernova Remnants This workshop aims to assemble leading experts in various fields of astrophysical big bangs for vibrant discussions and to foster new collaborations among participants. Program (last updated 2025.02.17) 17Feb. 10:00-10:10 Opening Remarks by Hiro Nagataki (RIKEN) Special Talk 10:10-11:10 (50+10) Daniel Kasen (U.C. Berkeley) Radiative Transfer Modeling of Explosive Transients NS mergers, Kilonovae, and Gravitational Waves 11:10-11:50 (30+10) Masaomi Tanaka (Tohoku U.) Decoding light curves and spectra of kilonovae 11:50-12:30 (30+10) Kenta Hotokezaka (U. Tokyo) Kilonova Nebular Emission 12:30-14:00 Lunch Break and Poster Session 14:00-14:40 (30+10) Kipp Cannon (U. Tokyo) Selection Effects in Gravitational-Wave Observations 14:40-15:20 (30+10) Koutarou Kyutoku (Chiba U.) Signature of hadron-quark crossover in binary-neutron-star mergers 15:20-15:50 Poster Presentations & Coffee Break 15:50-16:30 (30+10) Luca Baiotti (Osaka U.) Investigating ultra-high-density equations of state through gravitational waves from binary neutron stars mergers Supernovae & Gamma-Ray Bursts (Chair A. Mizuta) 16:30-17:10 (30+10) Nozomu Tominaga (NAOJ) Transient studies using Subaru/Hyper Suprime-Cam 17:10-17:50 (30+10) Tianshu Wang (UCB) Three-Dimensional Long-Term CCSN Simulations: New Insights and Challenges 18 Feb. Gamma-Ray Bursts 9:00-9:30 (25+5) Akira Mizuta (RIKEN) 3D relativistic GRB jet propagation in collapsars 9:30-10:00 (25+5) Jin Matsumoto (Fukuoka U.) Nonlinear dynamics of relativistic magnetized jet with field reversals 10:00-10:30 (25+5) Hirotaka Ito (RIKEN) Numerical simulations of photospheric emission in GRBs 10:30-11:00 (25+5) Maria Dainotti (NAOJ) GRBs and SNe Ia cosmology to cast the Hubble constant tension 11:00-11:30 Poster Presentations & Coffee Break 11:30-12:10 (30+10) Kunihito Ioka (Kyoto U.) GRB Cocoon + Scattering in FRB Neutron Stars 12:10-12:40 (25+5) Hajime Sotani (Kochi U.) Supernova gravitational waves and asteroseismology 12:40-14:00 Lunch Break & Poster Presentations 14:00-14:30 (25+5) Akira Dohi (RIKEN) Modeling of Clocked X-ray Bursters Progenitor Stars 14:30-15:10 (30+10) Hideyuki Umeda (U. Tokyo) Progenitors of low-mass Fe core collapse supernovae and properties of supernova explosions 15:10-15:40 (25+5) Lucy McNeill (Kyoto U.) Finite temperature treatment of white dwarf merger progenitors 15:40-16:10 Poster Presentations & Coffee Break Core-Collapse Supernovae 16:10-16:50 (30+10) Tomoya Takiwaki (NAOJ) Diversity of explosion mechanisms of core-collapse supernovae 16:50-17:30 (30+10) Hiroki Nagakura (NAOJ) Open issues in numerical modeling of core-collapse supernova 17:30-18:10 (30+10) Yudai Suwa (U. Tokyo) Probing supernova interiors with neutrinos 18:30-21:00 Banquet & Poster Presentations 19 Feb. Supernovae, Supernova Remnants, and Nucleosynthesis 10:00-10:40 (30+10) Ke-Jung Chen (ASIAA) Supernovae of very massive stars 10:40-11:20 (30+10) Masaomi Ono (ASIAA) Evolution of core-collapse supernovae from explosion to supernova remnant 11:20-12:00 (30+10) Hiroya Yamaguchi (JAXA) XRISM view of supernova remnants 12:00-12:40 (30+10) Shiu-Hang Lee (Kyoto U.) Super high-speed three-dimensional hydrodynamic simulations of supernova remnants and their applications in the era of microcalorimetric X-ray spectroscopy 12:40-14:00 Lunch Break 14:00-14:40 (30+10) Gilles Ferrand (U. Manitoba) Typing thermonuclear explosions from observations of young supernova remnants 14:40-15:20 (30+10) Nobuya Nishimura (U. Tokyo) Toward new nuclear astrophysics experiments for explosive nucleosynthesis in core-collapse supernovae 15:20-16:00 (30+10) Ryosuke Hirai (RIKEN) Supernovae in binary systems 16:00-17:00 (60) Coffee Break and Free Discussion
会場: 理化学研究所 和光キャンパス
イベント公式言語: 英語
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セミナー
Operator-algebraic approach to point processes
2025年2月14日(金) 15:00 - 17:00
佐藤 僚亮 (中央大学 理工学部 学振特別研究員PD)
A point process is a mathematical description of a particle system with random interactions, and it naturally appears in various areas of mathematical physics and mathematics, including statistical mechanics, random matrix theory, combinatorics, and representation theory. In particular, a random particle system with repulsive interactions is associated with a determinantal point process, in which the correlation of any number of particles is expressed in terms of the two-particle correlation via a determinant. Furthermore, this determinantal structure enables an algebraic analysis using CAR algebras, which are operator algebras determined by canonical anti-commutation relations. In the first half of the talk, we will review the relationship between determinantal point processes and operator algebras, with a focus on why operator algebras naturally lend themselves to analyses in probability theory and statistical mechanics. In the second half, based on recent work, we will examine the dynamic relationship between point processes and operator algebras, discussing how dynamics on CAR algebras give rise to stochastic processes on determinantal point processes.
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
Linking quantum error correction and gauge theories with quantum reference frames
2025年2月14日(金) 10:30 - 11:30
Philipp Hoehn (沖縄科学技術大学院大学 (OIST) 助教授)
Redundancy is the hallmark of both quantum error correction and gauge theories. In this talk, I will show that this analogy is not merely a coincidence but that there is a deeper underlying structural relationship. The key ingredient to this observation is quantum reference frames (QRFs), which constitute a universal tool for dealing with symmetries in quantum systems. They define a split between redundant and physical information in gauge systems, thereby establishing a notion of encoding in that context. This leads to an exact dictionary between (group-based) quantum error correcting codes and QRF setups. In stabilizer codes, this uncovers a correspondence between errors and QRFs: every maximal set of correctable errors generates a unique QRF, and each QRF is associated with a unique class of correctable errors. This allows for a reinterpretation of the Knill-Laflamme condition and novel insights into the relation between correctability and redundancy. The dictionary also reveals a novel error duality, based on Pontryagin duality, and somewhat akin to electromagnetic duality. Time permitting, I will illustrate these findings in surface codes, which can be understood as both codes and lattice gauge theories. These findings may find use in code design and quantum simulations of gauge theories.
会場: 研究本館 3階 345−347号室
イベント公式言語: 英語
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Application of genetics and genomics to breeding
2025年2月13日(木) 16:00 - 17:30
ジェフリ・フォーセット (数理創造プログラム 上級研究員)
Humans have domesticated and modified several plants and animals over the course of history to achieve food security. However, drastic changes are required in order to meet the needs of a growing population while facing global warming. In particular, utilizing and improving the productivity of unutilized or underutilized resources such as minor crops, aquatic species, and insects are thought to be essential. Here, I will provide an overview of how humans have been modifying organisms by selective breeding, the role of genetics and genomics in modern selective breeding, and the challenges we are currently facing. This talk will be aimed at non-experts/non-biologists and will cover the basics of genetics.
会場: 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
Mathematical Studies on Human Cooperation
2025年2月12日(水) 15:00 - 17:00
村瀬 洋介 (理化学研究所 計算科学研究センター (R-CCS) 離散事象シミュレーション研究チーム 研究員)
Cooperation is a fundamental part of human society. But from an evolutionary perspective, it remains a puzzle—why do people help others even when it costs them? In theory, selfish individuals should have an advantage over cooperators. To explain how cooperative behaviors evolved, researchers have proposed several mechanisms, among which direct and indirect reciprocity play key roles in human interactions. In this talk, I will present my research on the evolution of cooperation, focusing on these two mechanisms. I will begin with an introduction to game theory and evolutionary game theory, which help us understand how people make decisions in strategic situations. Then, I will discuss my study on the repeated Prisoner’s Dilemma, where we discovered a new class of strategies through mathematical analysis and large-scale computations [1]. Finally, I will talk about my research on indirect reciprocity, a process where people cooperate based on reputation [2].
会場: 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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ワークショップ
Pebbles in Planet Formation
2025年2月10日(月) - 13日(木)
Research on planet formation involves various approaches, including explorations of small solar system bodies, observations of protoplanetary disks, dust experiments, simulations, and theoretical studies. One of the primary objectives in this field is to develop a comprehensive theory that explains how kilometer-sized planetesimals form from micrometer-sized dust grains, drawing upon findings from these diverse research methods. This workshop will focus on the concept of pebbles, which play a crucial role in the planet formation process. Pebbles — typically defined as solids ranging from millimeter to centimeter in size — are intermediate building blocks in planet formation, though their definition varies depending on the context. Assuming pebbles has led to theoretical advances in mechanisms such as streaming instability and pebble accretion, which promote the formation and growth of planetesimals. Additionally, pebbles have been linked to barriers against dust growth, such as the bouncing barrier. Furthermore, observations of protoplanetary disks have revealed the size distribution and porosity of solids, while the strength and thermal conductivity of comets obtained by the Rosetta mission suggest the accumulation of pebbles due to disk instabilities. However, inconsistencies have been pointed out between pebble formation and theories of dust growth. This workshop aims to revisit and refine our understanding of solid materials implicated in planet formation, particularly in light of findings from solar system explorations and protoplanetary disk observations. We aim to reevaluate the definition and role of pebbles in the broader context of planet formation, with a special focus on the current challenges and open questions in the field. The workshop will include discussions of experiments and simulations of dust growth and collisions, and planetesimal formation mechanisms such as streaming instability. The workshop features keynote talks from the perspectives of explorations, observations, experiments, simulations, and theories, and we also call for presentations on related topics.
会場: 国立天文台三鷹キャンパス (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
Investigating the Crust Urca Process in Accretion Neutron Stars: Implications for Superburst Ignition and Hot Cooling Curve of MAXI J0556-332
2025年2月7日(金) 16:00 - 17:15
Hao Huang (Ph.D. Student, Institute of Modern Physics, China)
This seminar investigates the Urca cooling strength of the 63Fe-63Mn pair, which varies due to uncertainties in the spin-parity of 63Fe, relevant to the Island of Inversion at N = 40. We present simulations that analyze the impact of this cooling mechanism on the thermal evolution of neutron star crusts, focusing on superburst ignition and anomalous hot quiescent phase cooling of MAXI J0556-332. Additionally, we explore the potential crust Urca process through the anomalous cooling curve of MAXI J0556-332, fitting observational data to determine neutron star mass and radius preferences. Preliminary results suggest that neutron stars with a crust Urca process tend to have smaller masses and larger radii, highlighting the need for precise β-decay measurements to further understand these phenomena.
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
Fireworks in the cosmos: The Hidden Power of Nuclear Reactions
2025年2月7日(金) 14:00 - 15:15
Irin Sultana (Ph.D. Student, Department of Physics, Central Michigan University, USA)
Neutron stars in low-mass X-ray binaries, accreting hydrogen- or helium-rich material from a companion star, frequently exhibit thermonuclear runaways on their surfaces known as Type-I X-ray bursts (XRBs). These bursts are powered by nuclear processes, such as the triple-α process, the αp process, and the rapid proton capture process, which play a critical role in model-observation comparisons. In this study, we investigate the impact of nuclear reaction uncertainties on XRBs using the ONEZONE model (Cyburt et al., 2016), considering different accreted compositions and accretion rates for the binary systems that are within the range of observed burst sources. The study is carried out in two stages. First, we determine the burst ignition conditions by simulating the settling of the accreted material with a full reaction network and a semi-analytical model. Second, we perform a sensitivity analysis by varying proton- and alpha-induced reaction rates in JINA REACLIBV2.2 within their estimated uncertainties. We explore the influence of these reactions on the XRBs light curve and the final abundances. The findings highlight key nuclear reactions that significantly affect XRB observables and the final abundances produced, offering guidance for future experimental efforts to improve our understanding of the uncertainties in the reaction rates involved in XRBs.
会場: 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
A coarse-grained model of disordered RNA for simulations of biomolecular condensates
2025年2月6日(木) 16:00 - 17:00
安田 一希 (慶應義塾大学 大学院理工学研究科 博士課程)
Protein-RNA condensates are involved in a range of cellular activities. Coarse-grained molecular models of intrinsically disordered proteins have been developed to shed light on and predict single-chain properties and phase separation. An RNA model compatible with such models for disordered proteins would enable the study of complex biomolecular mixtures involving RNA. Here, we present a sequence-independent coarse-grained, two-bead-per-nucleotide model of disordered, flexible RNA based on a hydropathy scale. We parameterize the model, which we term CALVADOS-RNA, using a combination of bottom-up and top-down approaches to reproduce local RNA geometry and intramolecular interactions based on atomistic simulations and in vitro experiments. The model semi-quantitatively captures several aspects of RNA-RNA and RNA-protein interactions. We examined RNA-RNA interactions by comparing calculated and experimental virial coefficients, and non-specific RNA-protein interaction by studying reentrant phase behavior of protein-RNA mixtures. We demonstrate the utility of the model by simulating the formation of mixed condensates consisting of the disordered region of MED1 and RNA chains, and the selective partitioning of disordered regions from transcription factors into these, and compare the results to experiments. Despite the simplicity of our model we show that it captures several key aspects of protein-RNA interactions and may therefore be used as a baseline model to study several aspects of the biophysics and biology of protein-RNA condensates.
会場: 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
Mathematics of the Future, Science of the Future: Large Language Models and Their Applications
2025年2月6日(木) 14:00 - 16:00
三内 顕義 (京都大学 大学院理学研究科 特定准教授)
In recent years, the rapid development of large language models (LLMs) such as ChatGPT has given many researchers a strong impression that these systems truly exhibit “intelligence.” In this presentation, we first review the evolution of AI research, explaining how large language models go beyond conventional machine learning by enabling more “general” forms of learning. We then highlight the importance of “sensors” and “mathematical capability” as key factors that allow AI to autonomously carry out scientific tasks such as problem analysis, hypothesis generation, and proofs in fields like mathematics and physics. We also examine how proof assistants can address the issue of hallucinations in LLM outputs, and discuss the role of combinatorial creativity in accelerating interdisciplinary research. Finally, we introduce our “AI Mathematician” agent project, demonstrating how integrating large language models with proof assistants can open new horizons in mathematical sciences.
会場: 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
Master equations for general non-Markovian processes: the Hawkes process and beyond
2025年2月5日(水) 16:30 - 18:00
金澤 輝代士 (京都大学 大学院理学研究科 物理学・宇宙物理学専攻 准教授)
The Markovian process is one of the most important classes of stochastic processes. The Markovian process is defined as a stochastic process whose time evolution is independent of the system's entire history and has been extensively studied using the master equation and Fokker-Planck equation approaches. In contrast, non-Markovian processes -- where time evolution depends on the full history of the system -- have not been systematically explored, except for a few special cases, such as semi-Markovian processes. In this talk, we present a recent master-equation approach to general non-Markovian jump processes [1-4]. Beginning with a general non-Markovian jump process, we derive the corresponding master equation through a Markovian-embedding approach. The Markovian embedding is a scheme to add a sufficient number of auxiliary variables to convert a non-Markovian model to a high-dimensional Markovian model. For the case of our model, the one-dimensional non-Markovian model is shown to be equivalent to a Markovian stochastic field theory, and we derive the field master equation correspondingly [4]. As an application, we examine the nonlinear Hawkes process, a history-dependent and self-exciting model frequently used in studying complex systems [1-3]. Additionally, we explore the stochastic thermodynamic framework for general jump processes [5] as another example.
会場: 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
34件のイベント / 2025年
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