Lecture

Introduction to the Quantum Theory of Gravity via Asymptotic Safety

January 24 (Tue) - 26 (Thu), 2023

Prof. Ohta Nobuyoshi (Visiting Professor, Department of Physics, National Central University, Taiwan)

We give an introduction to the formulation towards the quantum theory of gravity using the functional (or exact) renormalization group, the so-called asymptotic safety. First we briefly explain the necessity of quantization of gravity and why the Einstein gravity is not sufficient for this purpose. Second, we introduce the functional renormalization group equation and explain what is the asymptotic safety program to achieve the quantum theory of gravity. This includes the notion of relevant, irrelevant and marginal operators, and it is important that there are finite number of relevant operators to make any prediction of quantum effects. This gives a nonperturbatively renormalizable theory of gravity. We then discuss various examples how the program may be applied to various theories, and summarize the current status of this approach. (Tentative schedule) [Day 1: Jan. 24, 2023] Free discussion: 9:30 - 10:30 Lecture 1: 10:30 - 12:00 Lunch: 12:00 - 13:30 Lecture 2: 13:30 - 15:00 Break: 15:00 - 15:30 Lecture 3: 15:30 - 17:00 [Day 2: Jan. 25, 2023] Free discussion: 9:30 - 10:30 Lecture 4: 10:30 - 12:00 Lunch: 12:00 - 13:30 Lecture 5: 13:30 - 15:00 Break: 15:00 - 15:30 Lecture 6: 15:30 - 17:00 [Day 3: Jan. 26, 2023] Q&A + discussion: 9:30 - 15:00

Venue: #535-537, 5F, Main Research Building

Event Official Language: English

An Introduction to Quantum Measurement Theory for Physicists

November 10 (Thu) - 12 (Sat), 2022

Dr. Masahiro Hotta (Assistant Professor, Department of Physics, Graduate School of Science, Tohoku University)

In this lecture, basic concepts in quantum measurement theory are introduced, including measurement operators and POVM's. The related topics are also picked up. Lecture 1: Nov. 10, 10:30 - 12:00 Lecture 2: Nov. 10, 13:30 - 15:00 Lecture 3: Nov. 10, 15:30 - 17:00 Lecture 4: Nov. 11, 10:30 - 12:00 Lecture 5: Nov. 11, 13:30 - 15:00 Lecture 6: Nov. 12, 10:30 - 12:00

Venue: #345-347, 3F, Main Research Building (Main Venue) / via Zoom

Event Official Language: English

Introduction to Topological Insulators: From Quantum to Classical Physics 4

April 27 (Wed) at 15:00 - 17:00, 2022

Dr. Tomoki Ozawa (Associate Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

In this set of lectures, I give an introduction to topological insulators. A goal is to provide an overall understanding of basic concepts of the physics of topological insulators to mathematicians and physicists with no prior knowledge on the subject. Very roughly speaking, topological insulators are materials whose wavefunctions show nontrivial topological structure in momentum space. Materials with topologically nontrivial wavefunction in momentum space have been found to host modes which are localized at the surface (edge) of the material: a property known as the bulk-edge correspondence. The bulk-edge correspondence results in experimentally observable signature of somewhat abstract notion of topology of the wavefunction in momentum space. Originally, topological insulators were found and studied for electrons in solid-state materials, which are quantum mechanical. However, certain properties of topological insulators, including the bulk-edge correspondence, have been found to hold also for purely classical materials, such as electromagnetic waves obeying Maxwell’s equations, or waves described by Newtonian mechanics. I will try to introduce topological insulators in a way general enough to be applied to quantum as well as classical materials. In the final part of the lectures, I take this opportunity to discuss some of my own works, where I studied some relations between the two-dimensional topological insulators and Kähler geometry.

Venue: via Zoom

Event Official Language: English

Introduction to Topological Insulators: From Quantum to Classical Physics 3

April 21 (Thu) at 15:00 - 17:00, 2022

Dr. Tomoki Ozawa (Associate Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

In this set of lectures, I give an introduction to topological insulators. A goal is to provide an overall understanding of basic concepts of the physics of topological insulators to mathematicians and physicists with no prior knowledge on the subject. Very roughly speaking, topological insulators are materials whose wavefunctions show nontrivial topological structure in momentum space. Materials with topologically nontrivial wavefunction in momentum space have been found to host modes which are localized at the surface (edge) of the material: a property known as the bulk-edge correspondence. The bulk-edge correspondence results in experimentally observable signature of somewhat abstract notion of topology of the wavefunction in momentum space. Originally, topological insulators were found and studied for electrons in solid-state materials, which are quantum mechanical. However, certain properties of topological insulators, including the bulk-edge correspondence, have been found to hold also for purely classical materials, such as electromagnetic waves obeying Maxwell’s equations, or waves described by Newtonian mechanics. I will try to introduce topological insulators in a way general enough to be applied to quantum as well as classical materials. In the final part of the lectures, I take this opportunity to discuss some of my own works, where I studied some relations between the two-dimensional topological insulators and Kähler geometry.

Venue: via Zoom

Event Official Language: English

Introduction to Topological Insulators: From Quantum to Classical Physics 2

April 14 (Thu) at 15:00 - 17:00, 2022

Dr. Tomoki Ozawa (Associate Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

In this set of lectures, I give an introduction to topological insulators. A goal is to provide an overall understanding of basic concepts of the physics of topological insulators to mathematicians and physicists with no prior knowledge on the subject. Very roughly speaking, topological insulators are materials whose wavefunctions show nontrivial topological structure in momentum space. Materials with topologically nontrivial wavefunction in momentum space have been found to host modes which are localized at the surface (edge) of the material: a property known as the bulk-edge correspondence. The bulk-edge correspondence results in experimentally observable signature of somewhat abstract notion of topology of the wavefunction in momentum space. Originally, topological insulators were found and studied for electrons in solid-state materials, which are quantum mechanical. However, certain properties of topological insulators, including the bulk-edge correspondence, have been found to hold also for purely classical materials, such as electromagnetic waves obeying Maxwell’s equations, or waves described by Newtonian mechanics. I will try to introduce topological insulators in a way general enough to be applied to quantum as well as classical materials. In the final part of the lectures, I take this opportunity to discuss some of my own works, where I studied some relations between the two-dimensional topological insulators and Kähler geometry.

Venue: via Zoom

Event Official Language: English

Introduction to Topological Insulators: From Quantum to Classical Physics 1

April 7 (Thu) at 15:00 - 17:00, 2022

Dr. Tomoki Ozawa (Associate Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

In this set of lectures, I give an introduction to topological insulators. A goal is to provide an overall understanding of basic concepts of the physics of topological insulators to mathematicians and physicists with no prior knowledge on the subject. Very roughly speaking, topological insulators are materials whose wavefunctions show nontrivial topological structure in momentum space. Materials with topologically nontrivial wavefunction in momentum space have been found to host modes which are localized at the surface (edge) of the material: a property known as the bulk-edge correspondence. The bulk-edge correspondence results in experimentally observable signature of somewhat abstract notion of topology of the wavefunction in momentum space. Originally, topological insulators were found and studied for electrons in solid-state materials, which are quantum mechanical. However, certain properties of topological insulators, including the bulk-edge correspondence, have been found to hold also for purely classical materials, such as electromagnetic waves obeying Maxwell’s equations, or waves described by Newtonian mechanics. I will try to introduce topological insulators in a way general enough to be applied to quantum as well as classical materials. In the final part of the lectures, I take this opportunity to discuss some of my own works, where I studied some relations between the two-dimensional topological insulators and Kähler geometry.

Venue: via Zoom

Event Official Language: English

Public Lecture for Darwin Day

February 17 (Wed) at 9:00 - 10:00, 2021

Prof. Catherine Beauchemin (Deputy Program Director, iTHEMS / Professor, Department of Physics, Ryerson University, Canada)

Japan, February 17, 2021, 09:00 AM JST Canada/USA, Feb 16, 2021, 07:00 PM Eastern Time Through mutations and genetic reassortment, a virus can mutate and the resulting virus variants can evade our drugs, our vaccines, and our body's own immune response. Using specific viruses like influenza, HIV or SARS-CoV-2 (the virus responsible for COVID-19) as examples, I will introduce the basics of how viruses replicate, and the processes via which mutations arise. *Detailed information about the seminar refer to the Prof. Beauchemin’s email.

Venue: via Zoom

Event Official Language: English

Toward the Practical Use of Quantum Computers

December 4 (Fri) at 10:30 - 12:00, 2020

Dr. Shunji Matsuura (Visiting Scientist, iTHEMS / Fundamental Researcher, Quantum Simulation Division, 1QBit, Canada)

量子コンピュータは古典コンピュータとは異なる原理に基づいて動いており、自然科学を含む様々な分野において大きな変化をもたらすと考えられている。特にこの数年の進展は著しく、量子計算の古典計算に対する優位性が実験的に初めて示されるなど、期待されているマイルストーンが着実に達成されていっている。一方で量子コンピュータの発展において常に障害となっているのがノイズである。量子状態はノイズの影響を受けやすく、現在の量子コンピュータにおいては量子ゲート操作を行うごとに状態の精度が減衰していってしまう。そのため、量子コンピュータにかける負担をできるだけ減らすようなアルゴリズムの開発や、計算結果からエラーを取り除く方法、観測回数をできるだけ減らす方法等、様々な研究が行われている。本講義ではこれら量子コンピュータの実用化に向けた最近の研究と今後の課題について話す。

Venue: via Zoom

Event Official Language: Japanese

Forefront of Modern Science: Frontiers in Mathematics, Astronomy, Physics, Biology and Computation

October 2 (Fri) at 16:20 - 17:50, 2020

Dr. Tetsuo Hatsuda (Program Director, iTHEMS)
Dr. Yuka Kotorii (Visiting Scientist, iTHEMS / Associate Professor, Mathematics Program, Graduate School of Advanced Science and Engineering, Hiroshima University / Visiting Scientist, Mathematical Analysis Team, RIKEN Center for Advanced Intelligence Project (AIP))
Dr. Shigehiro Nagataki (Deputy Program Director, iTHEMS / Chief Scientist, Astrophysical Big Bang Laboratory, RIKEN Cluster for Pioneering Research (CPR))
Dr. Makiko Nio (Senior Scientist, Quantum Hadron Physics Laboratory, RIKEN Nishina Center for Accelerator-Based Science (RNC))
Dr. Ryosuke Iritani (Research Scientist, iTHEMS)
Dr. Ai Niitsu
Dr. Shigenori Otsuka (Research Scientist, iTHEMS / Research Scientist, Data Assimilation Research Team, RIKEN Center for Computational Science (R-CCS))
Dr. Emi Yukawa (Assistant Professor, Department of Physics, Faculty of Science Division I, Tokyo University of Science)

Venue: Changed to Zoom

Event Official Language: Japanese

Public Lecture : Math meets Quantum Materials

September 29 (Tue) at 19:00 - 20:30, 2020

Prof. Hidetoshi Nishimori (Senior Visiting Scientist, iTHEMS / Specially Appointed Professor, Tokyo Institute of Technology)
Dr. Tomoki Ozawa (Visiting Scientist, iTHEMS / Associate Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

Public Lecture "Math meets Quantum Materials" for high school students and above will be held. The lecture will introduce the latest topics in mathematics and physics, such as topology and quantum computers, in an easy-to-understand manner. For more information and to register for the event, please click on the related links.

Venue: via Online

Event Official Language: Japanese

iTHEMS Intensive Course [5] : "Adaptive strategies of organisms, their mathematical bases" - Evolution of cooperation

June 26 (Fri) at 13:30 - 15:00, 2020

Prof. Yoh Iwasa (Senior Advisor, iTHEMS / Professor, Kwansei Gakuin University / Professor Emeritus, Kyushu University)

Living systems exhibit features distinct from nonliving physical systems: their structure and behaviors appear to be chosen adaptive. They are the outcomes of evolution. Mathematical formalisms developed in engineering and social sciences (e.g. control theory, game theory, evolutionary game theory) are sometimes very useful in biology.

Venue: via Zoom

Event Official Language: English

iTHEMS Intensive Course [3] : "Adaptive strategies of organisms, their mathematical bases" - Masting, synchronized reproduction of trees: Coupled chaotic system

June 25 (Thu) at 13:30 - 14:30, 2020

Prof. Yoh Iwasa (Senior Advisor, iTHEMS / Professor, Kwansei Gakuin University / Professor Emeritus, Kyushu University)

Living systems exhibit features distinct from nonliving physical systems: their structure and behaviors appear to be chosen adaptive. They are the outcomes of evolution. Mathematical formalisms developed in engineering and social sciences (e.g. control theory, game theory, evolutionary game theory) are sometimes very useful in biology.

Venue: via Zoom

Event Official Language: English

iTHEMS Intensive Course [2] : "Adaptive strategies of organisms, their mathematical bases" - Dynamic optimization models for growth and reproduction

June 19 (Fri) at 13:30 - 15:00, 2020

Prof. Yoh Iwasa (Senior Advisor, iTHEMS / Professor, Kwansei Gakuin University / Professor Emeritus, Kyushu University)

Living systems exhibit features distinct from nonliving physical systems: their structure and behaviors appear to be chosen adaptive. They are the outcomes of evolution. Mathematical formalisms developed in engineering and social sciences (e.g. control theory, game theory, evolutionary game theory) are sometimes very useful in biology.

Venue: via Zoom

Event Official Language: English

iTHEMS Intensive Course [1] : "Adaptive strategies of organisms, their mathematical bases" - Sex expression and sex allocation of marine organisms

June 18 (Thu) at 13:30 - 15:00, 2020

Prof. Yoh Iwasa (Senior Advisor, iTHEMS / Professor, Kwansei Gakuin University / Professor Emeritus, Kyushu University)

Living systems exhibit features distinct from nonliving physical systems: their structure and behaviors appear to be chosen adaptive. They are the outcomes of evolution. Mathematical formalisms developed in engineering and social sciences (e.g. control theory, game theory, evolutionary game theory) are sometimes very useful in biology.

Venue: via Zoom

Event Official Language: English

RIKEN Open Campus in Kobe

November 9 (Sat) at 10:00 - 16:30, 2019

Dr. Takumi Doi (Senior Research Scientist, iTHEMS / Senior Research Scientist, Quantum Hadron Physics Laboratory, RIKEN Nishina Center for Accelerator-Based Science (RNC))

RIKEN Open Campus in Kobe will be held on Nov.9, 2019. Dr. Emiko Hiyama (Kyushu Univ.) and Dr. Takumi Doi (Nishina Center / iTHEMS) will give lectures on computational nuclear and particle physics at Kobe IIB building where SUURI-COOL Kobe is located. Please inform the news to anybody who are interested in visiting RIKEN Kobe.

Venue: Integrated Innovation Building (IIB)

Event Official Language: Japanese

Outlook for Industrial Applications of Quantum Computers

September 4 (Wed) at 15:30 - 18:00, 2019

Dr. Yuya Nakagawa (QunaSys Inc.)

Venue: Okochi Hall

Broadcast:R311, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: Japanese

SUURI-COOL (Kyushu) Lecture

July 31 (Wed) - August 2 (Fri), 2019

Dr. Takumi Doi (Senior Research Scientist, iTHEMS / Senior Research Scientist, Quantum Hadron Physics Laboratory, RIKEN Nishina Center for Accelerator-Based Science (RNC))

SUURI-COOL (Kyushu) at the Ito-campus of Kyushu Univ. will be launched on July 31, 2019. As a first event at SUURI-COOL (Kyushu), the following lecture by Takumi Doi (RIKEN Nishina Center/iTHEMS) will be held. Feel free to join if you will be around Ito-campus. Nuclei, many-body systems of baryons as protons and neutrons, are ultimately consist of elementary particles of quarks and gluons and their properties are governed by quantum chromodynamics (QCD). Recently, a new theoretical method is developing in lattice QCD, the first-principles calculation of QCD, and the new era is dawning where nuclear physics is constructed directly based on QCD. In this lecture, I first introduce the formulation of lattice QCD. I will then discuss the theoretical foundation and the latest numerical results about the lattice QCD study of hadron interactions, the key quantities to construct nuclear physics from QCD. I will also give a lecture on computational science, in particular, about supercomputers.

Venue: SUURI-COOL (Kyushu)

Event Official Language: English

First M87 Event Horizon Telescope Results: The Shadow of the Supermassive Black Hole

May 24 (Fri) at 14:00 - 15:00, 2019

Dr. Yosuke Mizuno (Frankfurt University, Germany)

The Event Horizon Telescope (EHT) has mapped the central compact radio source of the elliptical galaxy M87 at 1.3 mm with unprecedented angular resolution. These images show a prominent ring with a diameter of ~40 micro-arcsecond, consistent with the size and shape of the lensed photon orbit encircling the “shadow” of a supermassive black hole. The ring is persistent across four observing nights and shows enhanced brightness in the south. Here we consider the physical implications of the asymmetric ring seen in the 2017 EHT data. To this end, we construct a large library of models based on general relativistic magnetohydrodynamic simulations and synthetic images produced by general relativistic ray tracing. We compare the observed visibilities with this library and confirm that the asymmetric ring is consistent with earlier predictions of strong gravitational lensing of synchrotron emission from a hot plasma orbiting near the black hole event horizon. Overall, the observed image is consistent with expectations for the shadow of a spinning Kerr black hole as predicted by general relativity. If the black hole spin and M87’s large scale jet are aligned, then the black hole spin vector is pointed away from Earth. Models in our library of non-spinning black holes are inconsistent with the observations as they do not produce sufficiently powerful jets. We also briefly discuss the possibility of the alternatives to a black hole for the central compact object.

Venue: #435-437, Main Research Building

Event Official Language: English

Introduction to Quantum Computation

May 13 (Mon) - 15 (Wed), 2019

Dr. Shunji Matsuura (Fundamental Researcher, Quantum Simulation Division, 1QBit, Canada)

The schedule of the lectures on "Quantum Computation" by Dr. Shunji Matsuura (1QBit) is as follows. May 13 (Mon) [Lecture 1] 10:00-11:30, [Lecture 2] 14:00-15:30 May 14 (Tues) [Lecture 3] 10:00-11:30, [Lecture 4] 14:00-15:30 May 15 (Wed) [Lecture 5] 10:00-11:30, [Lecture 6] 14:00-15:30

Venue: Nishina Hall

Event Official Language: English