セミナー
723 イベント
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Introduction to 1QBit Open Software QEMIST "Quantum-Enabled Molecular ab Initio Simulation Toolkit"
2019年10月17日(木) 13:30 - 15:00
松浦 俊司 (Fundamental Researcher, Quantum Simulation Division, 1QBit, Canada)
会場: 研究本館 433号室
イベント公式言語: 英語
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Dark matter search in extended dwarf spheroidal galaxies with CTA
2019年10月11日(金) 14:00 - 15:00
廣島 渚 (数理創造プログラム 特別研究員)
The nature of dark matter (DM) is still a big mystery. Among the varieties of candidates, Weakly Interacting Massive Particle (WIMP) is one of the most promising ones. Gamma-ray observations of dwarf spheroidal galaxies (dSphs) by Fermi satellites put the strongest constraints at mDM<~ a few hundreds of GeV. In the near future, Cherenkov Telescope Array (CTA) starts its operations and expect to probe WIMP of mDM>~O(1)TeV. Different from previous experiments, spatial distributions of DM in dSphs are resolved with CTA. In this talk, I explain how it affects our accessibility to DM annihilation cross-section.
会場: セミナー室 (132号室)
イベント公式言語: 英語
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セミナー
Finite N corrections to the superconformal index from D3-brane analysis in AdS_5/CFT_4
2019年10月8日(火) 15:30 - 17:00
荒井 玲於奈 (東京工業大学 博士課程)
In the context of the AdS/CFT, the Type IIB superstring theory on AdS_5 \times SE_5 corresponds to an N=1 quiver gauge theory, where SE_5 is a five-dimensional Sasaki-Einstein manifold. We study this correspondence by using the superconformal index, which contains the information of the BPS spectrum in the theory. It is known that the index of the large N limit is evaluated by the Kaluza-Klein modes on SE_5 and the agreement with CFT results was confirmed in many examples. In this talk, we consider the finite N corrections to the index on the gravity side as a next step. To do this, we focus on a single D3-brane wrapped around a three-cycle on SE_5. Because there are in general several three-cycles on SE_5, we need to sum up contributions of these single D3-branes. By using the D3-brane analysis, we propose a prescription to calculate the finite N corrections to the index. We explain our prescription through some examples and see the agreement with the CFT results calculated by the localization method.
会場: セミナー室 (160号室)
イベント公式言語: 英語
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A new lamppost in dark matter searches: Composite Dark Matter
2019年10月1日(火) 10:00 - 18:00
リナルディ エンリコ (数理創造プログラム 研究パートタイマー Ⅰ)
In the search for the nature of dark matter many particle physics models are proposed. Models originating from a new strongly coupled dark sector, similar to QCD and Nuclear Physics, give rise to Composite Dark Matter particles. These models are hard to study, but they have a very interesting phenomenology with clear signals that are distinct from the usual WIMP candidates. To make robust predictions in Composite Dark Matter models one often needs to investigate non-perturbative effects due to the strong dynamics. In my talk I will explain how Lattice Field Theory methods and numerical simulations are well suited for this task and contribute to a solid uncertainty quantification. A variety of detection signals can be studied with lattice simulations, from dark matter self interactions to interactions with regular matter and even signals of dark phase transitions generating primordial gravitational waves.
会場: 研究本館 424-426号室
イベント公式言語: 英語
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セミナー
Angular power spectrum analysis on current and future high-energy neutrino data
2019年9月18日(水) 14:00 - 15:00
Ariane Dekker (Faculty of Science, University of Amsterdam, Netherlands)
The astrophysical neutrino events that have been measured in the last couple of years show an isotropic distribution on the sky. To constrain the contribution of source populations to the observed neutrino sky, we consider isotropic and anisotropic components of the diffuse neutrino data. We simulate through-going muon neutrino events by applying statistical distributions for the fluxes of extra-galactic sources and investigate the sensitivities of current (IceCube) and future (IceCube-Gen2 and KM3NeT) experiments. I will show that the angular power spectrum is a powerful probe to assess the angular characteristics of neutrino data and demonstrate that we are already constraining rare and bright sources with current IceCube data. In addition, I will investigate the decay and annihilation of very heavy dark matter as a potential neutrino source suggested by the excess in HESE data. We apply our angular power spectrum analysis to HESE data for different channels, allowing us to interpret the observed neutrino sky and perform a sensitivity forecast.
会場: 研究本館 1階 160号室
イベント公式言語: 英語
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セミナー
iTHEMS Biology Seminar
2019年9月13日(金) 15:00 - 17:20
久保田 浩行 (九州大学 生体防御医学研究所 教授)
上江洲 安史 (NTTコミュニケーション科学基礎研究所 感覚運動研究グループ 研究員)Timetable 15:00-16:00 Hiroyuki Kubota (Kyushu Univ.) 16:00-16:20 Break 16:20-17:20 Yasufumi Uezu (NTT) Time: 15:00-16:00 Speaker: Hiroyuki Kubota (Kyushu Univ.) Title: Regulation of insulin action by temporal patterns of insulin Abstract: Cells respond to various extracellular stimuli through a limited number of signaling pathways. One strategy to process such stimuli is to code the information into the temporal patterns of molecules. Almost all hormones exhibit distinct temporal patterns and the importance of their patterns has been reported. However, the mechanisms of how hormones regulate downstream molecules depending on their temporal patterns remain unknown. We focused on insulin which plays crucial roles on glucose homeostasis and shows several temporal patterns in vivo. In this study, we show how the Insulin signaling pathway processes the information encoded into the temporal patterns of blood insulin using a cultured cell line and mice. We found that insulin patterns selectively regulate the insulin-AKT pathway, metabolites, and mRNAs. Mathematical modeling revealed the mechanisms via differences in network structures and from sensitivity and time constants. Given that almost all hormones exhibit distinct temporal patterns, temporal coding may be a general principle of system homeostasis by hormones. Time: 16:20-17:20 Speaker: Yasufumi Uezu (NTT) Title: Source-filter interaction brings various representation in speech and singing voice Abstract: Speech plays a very important role in human communication. The source-filter interaction, a model that takes into account the actual speech production process, assumes that the sound source generation mechanism and the vocal-tract filter are not independent, but affect each other physiologically and acoustically. It is known that the source-filter interaction brings about non-linearity of speech and singing, such as singing voice with a loud volume and wide pitch range like an opera singer, or voice register transition where the vocal suppression and/or the voice pitch jump occurs. I would like to introduce my researches targeting non-linear vocalization phenomena due to the source-filter interaction and results of measuring and analyzing the time waveform of speech sound and vocal-fold vibrations through measurement experiments.
会場: 研究本館 424-426号室
イベント公式言語: 日本語
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セミナー
量子多体系入門-格子模型を中心に-
2019年9月5日(木) - 6日(金)
桂 法称 (東京大学 大学院理学系研究科 物理学専攻 准教授)
2019.09.05 @ 理研 研究本館 535-537号室 10:00-11:30 (1)イントロダクション -連続系から格子系へ- 13:00-14:30 (2)自由フェルミオン系と二次形式 15:00-16:30 (3)自由ボゾン系と二次形式 2019.09.06 @ 理研 研究本館 435-437号室 10:00-11:30 (4)古典・量子Ising模型 13:00-14:30 (5)量子スピン系の話題 15:00-16:30 (6)まとめと展望
会場: 研究本館 535-537号室 / 研究本館 435-437号室
イベント公式言語: 日本語
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Introduction to Quantum Annealing: from Fundamentals to Applications
2019年9月2日(月) - 3日(火)
入江 広隆 (数理創造プログラム 客員研究員 / 株式会社デンソー 先端技術研究所 アシスタントマネージャー)
Sep. 2 (Mon) 10:30-12:00, 13:30-15:00, 15:30-17:00 Lecture 1: What is quantum annealing and quantum computation? Lecture 2: Quatum Ising models as flux-qubit degree of freedom Lecture 3: Basic usage of quantum annealer Sep. 3 (Tue) 10:30-12:00, 13:30-15:00, 15:30-17:00 Lecture 4: Optimization problems and computational complexity Lecture 5: Real-world applications Lecture 6: Some other topics Room: 435-437 (main research building): Sep.2 (Mon) am 424-426 (main research building): Sep.2 (Mon) pm & Sep.3 (Tue) am+pm Abstract: Quantum annealing is a quantum-computational scheme which tackles computationally hard optimization problems. Its quantum-mechanically implemented machine, called quantum annealer, is commercially manufactured by D-Wave Systems, Inc., and is currently available with more than 2000 quantum bits. In this two-day lecture, I would like to discuss fundamental aspects of quantum annealing (1st day) and its real-world applications (2nd day). In particular, I try to overview the current status of the machine and several problems which we should theoretically overcome. In the first day, I will start with discussing what is quantum annealing and then review how quantum Ising model is implemented with flux-qubit degree of freedom. Later on, I will discuss the basic usage of the quantum annealer as a preparation for applications. In the second day, I will first summarize several classes of optimization problems and their computational complexity, and then discuss examples of real-world applications of quantum annealing. Finally, if I have enough time, I would like to discuss other related topic on quantum annealing.
会場: 研究本館 435-437号室 / 研究本館 424-426号室
イベント公式言語: 英語
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Physics of Gamma-Ray Bursts: Emission Mechanism, Particle Acceleration, Nucleosynthesis, and Gravitational Waves
2019年8月17日(土) 12:00 - 13:00
長瀧 重博 (数理創造プログラム 副プログラムディレクター / 理化学研究所 開拓研究本部 (CPR) 長瀧天体ビッグバン研究室 主任研究員)
Gamma-Ray Bursts (GRBs) are very powerful, special explosions of massive stars. In the explosions, highly relativistic jets are launched from progenitor stars and lots of gamma-rays are emitted from the jets. It is also suggested by gravitational wave detection with follow-up observations that (short duration) GRBs are triggered by neutron star mergers (NSMs). In this talk, physics of GRBs are introduced with some of our recent studies. I would like to introduce how the relativistic jets will emit bunch of gamma-rays, and how particle acceleration happens in the relativistic jets. I also would like to introduce our recent studies on r-process nucleosynthesis & gravitational wave emission at NSMs. Location: 50A-5132
会場: Lawrence Berkeley National Laboratory (Berkeley, California)
イベント公式言語: 英語
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セミナー
Complex analysis on a neighborhood of a complex submanifold and its applications
2019年7月30日(火) 16:00 - 18:10
小池 貴之 (大阪市立大学 大学院理学研究科 数学教室 講師)
Plan of the seminar: we separate each talk into two. In the first 60 minutes the speaker gives an introductory talk for non-mathematicians. After a short break, the second 60 minutes is spent for a bit more detailed talk for mathematicians (working in other areas). We welcome you joining both parts of the seminar or only the first/second half. Abstract: We explain our recent study on the complex analytic structure of a small tubular neighborhood of a complex submanifold, which is based on T. Ueda's classification theory. We also explain how to apply them to: (i) a study on (non-) existence of a smooth Hermitian metric on a nef line bundle over a projective manifold with semi-positive curvature, and (ii) a study on non-projective and non-Kummer K3 surfaces.
会場: セミナー室 (160号室)
イベント公式言語: 英語
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Introduction to magnitude of metric spaces
2019年7月22日(月) 13:00 - 15:00
大内 元気 (数理創造プログラム 基礎科学特別研究員)
Leinster introduced the notion of magnitude of a metric space. It is a real number measuring the effective number of points in a metric space. In this talk, I will review generalizations of metric spaces (e.g. asymmetric metric spaces). After that, I would like to talk about the definition, examples and fundamental properties of magnitude.
会場: セミナー室 (160号室)
イベント公式言語: 英語
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Introduction to Schroedinger Operators
2019年7月12日(金) 16:00 - 18:10
三上 渓太 (数理創造プログラム 研究員)
Plan of the seminar: we separate each talk into two. In the first 60 minutes the speaker gives an introductory talk for non-mathematicians. After a short break, the second 60 minutes is spent for a bit more detailed talk for mathematicians (working in other areas). We welcome you joining both parts of the seminar or only the first/second half. Abstract: In this seminar, I will talk about mathematical study of Schroedinger operators (or Schroedinger equation). Part 1: I will talk about what mathematicians do to find a solution to Schroedinger equation. The goal of the first part is to be able to check the existence of solutions of Schroedinger equations in terms of decay/growth rate of potentials. Part 2: I will talk about what can we say about solutions to Schroedinger equation constructed in the first part. Especially, the relationship to the corresponding classical mechanic is introduced.
会場: セミナー室 (160号室)
イベント公式言語: 英語
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セミナー
Large scale dynamics of integrable systems
2019年7月12日(金) 16:00 - 17:00
Takato Yoshimura (King's college London, UK)
Hydrodynamics has been a universal tool to study the large scale (long-wavelength) dynamics of interacting many-body systems. It had not been, however, applied to integrable systems until 2016 when two papers, one of which is ours [Physical Review X 6 (4), 041065, (2016)], provided a first legitimate hydrodynamic theory of integrable systems that incorporates the anomalous number of conserved quantities in those systems. The key idea of the theory rests upon the use of thermodynamic Bethe ansatz that allows us to express the essential ingredients in hydrodynamics, densities and currents average of conserved charges, in terms of the quasi-particle basis. In this talk I will review this new hydrodynamic theory, coined generalized hydrodynamics (GHD). I will first introduce the basics of GHD, highlighting the difference with the conventional hydrodynamics (i.e. hydrodynamics for non-integrable systems). I will then present some recent developments in the theory, such as the exact computation of the Drude weight and hydrodynamic correlation functions.
会場: Building 14 #213, Yagami campus, Keio University
イベント公式言語: 英語
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セミナー
ABBL/iTHEMS/r-EMU Joint Seminar: Towards systematic and consistent nuclear data inputs for astrophysical r-process with Bayesian approaches
2019年6月28日(金) 14:00 - 15:00
ハオジヤオ・リアン (理化学研究所 仁科加速器科学研究センター (RNC) 量子ハドロン物理学研究室 専任研究員)
This is his 2nd seminar talk for non-experts of nuclear physics, following the 1st one on 18th Jan. 2019. Abstract: In this interdisciplinary talk, I will start with some basic concepts as well as some frontiers of nuclear physics, and then introduce the roles of nuclear data inputs for the study of astrophysical rapid neutron-capture process (r-process), which is responsible for the creation of approximately half the abundances of the atomic nuclei heavier than iron. Recent progress in nuclear physics focuses on improving the accuracy of crucial nuclear inputs, such as nuclear masses, beta-decay half-lives. Nevertheless, in most of the studies these inputs are investigated individually. One of our ongoing attempts is to organize the crucial nuclear inputs in a systematic and consistent way, together with Bayesian and/or machine learning approaches, which are able to provide not only the theoretical results but also the corresponding uncertainties.
会場: 研究本館224-226室
イベント公式言語: 英語
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Asymmetric metric and coarse geometry
2019年6月20日(木) 16:00 - 18:10
児玉 大樹 (数理創造プログラム 客員研究員 / 東北大学 材料科学高等研究所 (AIMR) 助教)
Plan of the seminar: we separate each talk into two. In the first 60 minutes the speaker gives an introductory talk for non-mathematicians. After a short break, the second 60 minutes is spent for a bit more detailed talk for mathematicians (working in other areas). We welcome you joining both parts of the seminar or only the first/second half. Abstract: For most of mathematicians, metric is symmetric. However, we can define asymmetric metric without any difficulty. "Coarse" is a notion to describe some large scale viewpoint. For example, the set of real numbers is coarse equivalent to the set of integers (with respect to standard metric). I will discuss asymmetric metric space in "coarse" sense. Part 1: I will define metric space and asymmetric metric space. I will also explain a notion of coarse equivalence. Part 2: I will discuss what kind of asymmetric metric space is not coarse equivalent to (symmetric) metric space. I also would like to give other generalizations of metric.
会場: セミナー室 (160号室)
イベント公式言語: 英語
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セミナー
Using combined Particles-in-MHD-Cells to model particle acceleration in astrophysical shocks
2019年6月17日(月) 14:00 - 15:00
Allard Jan van Marle (Research Professor, Ulsan National Institute of Science and Technology, Republic of Korea)
Astrophysical shocks can accelerate charged particles through diffusive shock acceleration. This process involves repeated shock crossings where the particle gains energy from collisions with the electromagnetic field. Eventually, these particles will reach relativistic speeds and can be observed as cosmic rays. In order to simulate this process, we need a method that can handle both the large-scale structure of astrophysical shocks, as well as the behaviour of individual particles. We achieve this by combining the classical magnetohydrodynamics (MHD) and particle-in-cell (PIC) methods. This allows us to describe the thermal plasma of the shock through MHD, while simultaneously using PIC to follow the movement of non-thermal particles as they are accelerated. Our results show a complicated interaction that destabilizes the shock, reducing the efficiency with which particles can be accelerated.
会場: セミナー室 (132号室)
イベント公式言語: 英語
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Quantum physics and science with open-source software: QuTiP, the Quantum Toolbox in Python
2019年6月13日(木) 10:00 - 11:30
ナタン・シャマー (理化学研究所 開拓研究本部 (CPR) Nori理論量子物理研究室 特別研究員)
I will address the rise of open source software based on the Python language ecosystem in quantum physics research, in particular with relevance to quantum technology and quantum computing. I will introduce the Quantum Toolbox in Python, QuTiP, a very popular software in the quantum tech community, whose core development has revolved around Prof. F. Nori’s group at RIKEN since 2011. QuTiP is open-source software for simulating the dynamics of closed and open quantum systems, and is used for quantum information science and cavity quantum electrodynamics studies. The QuTiP ecosystem has grown considerably in the past years, with many quantum tech libraries using its functionalities, similarly to what has happened for AstroPy in the astrophysics community. Following the seminar, an interactive session will illustrate some features of this software package library. I will also show, drawing from recent research examples, how everyone can build its own library. Only a laptop with wifi working is required to join the hands-on session.
会場: 仁科ホール
イベント公式言語: 英語
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Quantum Mechanics of an Evaporating Black Hole
2019年6月6日(木) 15:30 - 17:00
野村 泰紀 (Director, Berkeley Center for Theoretical Physics, University of California, Berkeley, USA)
会場: セミナー室 (160号室)
イベント公式言語: 英語
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セミナー
ABBL-iTHEMS Joint Seminars (Following r-EMU seminar 13:30-15:00)
2019年5月31日(金) 15:15 - 17:35
15:15-15:35 Hiroyuki Sagawa (ICRR, U.Tokyo) “Recent TA Results and the extension status for the study of the highest-energy cosmic rays” 15:35-16:30 Igor Tkachev (Russian Academy of Sciences) “Axion stars: from birth to death” 16:30-16:40 Break 16:40-17:35 Peter Tinyakov (U. Libre de Bruxelles) “Solar mass black holes and dark matter"
会場: 研究本館 435-437号室
イベント公式言語: 英語
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Certain invariants as dimension
2019年5月24日(金) 16:00 - 18:10
大内 元気 (数理創造プログラム 基礎科学特別研究員)
Plan of the seminar: we separate each talk into two. In the first 60 minutes the speaker gives an introductory talk for non-mathematicians. After a short break, the second 60 minutes is spent for a bit more detailed talk for mathematicians (working in other areas). We welcome you joining both parts of the seminar or only the first/second half. Abstract: In this talk, I would like to talk about certain invariants that look like dimension. This talk has independent two parts. In part 1, I will talk about finite metric spaces. In 2013, Leinster introduced the notion of magnitude of finite metric spaces. It measures effective number of points in finite metric spaces. Considering magnitude and scale transformation, Leinster and Willerton defined dimension of finite metric space with scale. I will explain the definition of magnitude of finite metric spaces and see examples. In part 2, I will talk about derived categories of smooth projective varieties or finite dimensional algebras. In 2014, Dimitrov, Heiden, Katzarkov and Kontsevich introduced the notion of entropy of endofunctors of derived categories. It measures complexity of endofunctors under iteration. Serre functor is an autoequivalence of derived category, that describes Serre duality. Entropy of Serre functor looks like dimension of derived categories. I will talk about known results for entropy of Serre functors and some related topics.
会場: セミナー室 (160号室)
イベント公式言語: 英語
723 イベント
イベント
カテゴリ
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- iTHEMSコロキウム
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- iTHEMSセミナー
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