Volume 78

iTHEMS Weekly News Letter

Seminar Report

iTHEMS Public Lectures at RIKEN Kobe Open Campus 2019

2019-11-13

iTHEMS Public Lectures were held at the 8th floor of the RIKEN IIB building on Nov.9 as a part of the RIKEN Kobe Open Campus 2019. Takumi Doi (RNC/iTHEMS) and Emiko Hiyama (Kyushu U./RNC) gave lectures on computational nuclear and particle physics. Takumi introduced the history and concept of computers with full of Kansai jokes, followed by an explanation of the recent results from massive parallel computers such as the K computer. Emiko explained why quantum systems with more than 3 particles are fundamentally different from the two-body systems, and how to overcome the difficulty by computational approach. Both lectures were pedagogical enough for non-scientists and stimulated interesting questions from the audience.

RIKEN Open Campus in Kobe image

Upcoming Events

Seminar

Variational methods in quantum annealing thumbnail

QuCoIn Seminar

Variational methods in quantum annealing

November 15 (Fri) at 13:30 - 15:00, 2019

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

The rapid progress in the manufacturing of quantum computing hardware has opened up the possibility of exploring its application in solving computationally challenging problems. In this work, we present variational methods in quantum annealing for solving problems more efficiently than the standard adiabatic methods. Important limitations common to all near-term quantum devices include the absence of error correction and the short coherence time, which restrict the computational power of these systems. Therefore, shortening the time taken to perform an individual run of a quantum algorithm and making the annealing process noise resilient is essential for successfully obtaining accurate results.
The efficiency of the methods is demonstrated in the ground-state energy estimation of simple molecular systems. Compared with the standard annealing method, the variational algorithms show significant improvements in the annealing time required to achieve a high accuracy.

Venue: #433, Main Research Building, RIKEN

Event Official Language: English

Colloquium

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MACS ColloquiumSupported by iTHEMSSUURI-COOL (Kyoto)

The 10th MACS Colloquium

November 15 (Fri) at 14:45 - 18:45, 2019

Nami Sakai (Chief Scientist, Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research (CPR))
Kazuya Watanabe (Professor, Graduate School of Science, Kyoto University)

14:45- Teatime
15:00- Talk by Dr. Nami Sakai
16:15- Talk by Prof. Kazuya Watanabe
17:45- Discussion

The 10th MACS colloquium supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good confectionery at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Event Official Language: Japanese

Seminar

ABBL-iTHEMS Joint Astro Seminar

A multiscale study of turbulent heating in hot accretion flows

November 18 (Mon) at 14:00 - 15:00, 2019

Yohei Kawazura (Assistant Professor, Tohoku University)

Recently, the Event Horizon Telescope (ETH) collaboration revealed the stunning picture of radiation from the vicinity of the black hole. For accurate interpretation of the observation, it is crucial to understand the nature of plasma in the accretion disk. The disks that EHT is observing are called radiatively inefficient accretion flows, in which the plasma is hot and dilute, and consequently collisionless. In collisionless plasma, ions and electrons can have different temperatures as they do not thermally relax through Coulomb interaction. The ion-to-electron temperature ratio is the key to interpreting the observation because we can measure only the electrons' energy via radiation. To study ion and electron heating, kinetic treatment, rather than hydrodynamic treatment, is necessary. However, kinetic plasma turbulence is an extremely challenging subject. Therefore, we utilized gyrokinetics that is widely used in magnetic confinement fusion research. Our new multiscale approach treats a "large scale" where turbulence is driven by magnetorotational instability via MHD, and a "small scale" where turbulence is dissipated via gyrokinetics. Using this approach, we formulated a prescription of ion-to-electron heating ratio. In my talk, I will also present basic knowledge that is necessary to study collisionless turbulent heating.

Venue: Seminar Room #132, 1F Main Research Building, RIKEN

Event Official Language: English

Conference

2019 RIKEN Symposium: Understand to Predict the properties of Things and Matters through Computational Calculations ~ Data Science, Natural Intelligence and Category Theory~

December 23 (Mon) at 9:50 - 18:10, 2019

This workshop is supported by RIKEN iTHEMS (RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program).

Venue: Okochi Hall, 1F Laser Science Laboratory, RIKEN

Event Official Language: Japanese

Workshop

RIKEN-Kyushu workshop on particle, nuclear and astrophysics thumbnail

RIKEN-Kyushu workshop on particle, nuclear and astrophysics

December 23 (Mon) - 24 (Tue), 2019

Organizers
Emiko Hiyama (Kyushu U./RIKEN)
Hiroshi Suzuki (Kyushu U.)
Tetsuo Hatsuda (RIKEN)

Venue: Faculty of Science, Ito Campus, Kyushu University

Event Official Language: Japanese

Person of the Week

Takashi Sakajo thumbnail

Self-introduction: Takashi Sakajo

2019-11-11

I am a full professor of Department of mathematics at Kyoto University, and a project professor of Liaison Center in Mathematics in RIMS at Kyoto University. From Nov. 2019, I am appointed to a senior visiting scientist at RIKEN iTHEMS. My educational background in undergraduate/graduate courses at Kyoto University was mathematics, but I have been keeping strong interests in the other fields of sciences. My expertise in research is applied mathematics, especially mathematical fluid dynamics, in which I would like to understand highly nonlinear and complex fluid phenomena observed in the evolutions of incompressible fluid motions from mathematical points of view theoretically as well as numerically. In addition to those academic topics, I am keen to conduct many interdisciplinary studies with people from the other disciplines (meteorology, medical, material science etc.) and industries. I am the chief coordinator of Math Clinic at MACS program in Kyoto University. These interdisciplinary activities are not just for applying existing mathematical theories, but for exploring new future problems for mathematical sciences from modern world. I am very happy to be a member of iTHEMS, where I can share the same interests with the members.

Research Topics:
• Topological Flow Data Analysis
• Dissipative weak solutions of the Euler equations and turbulence theory
• Vortex dynamics
• Flow control of vortex dominated flows
• Singularity formation and long-time behavior of vortex dynamics
• Applied and computational complex analysis (ACCA)
• Uncertainty Quantification (Data Assimilations)
• Interdisciplinary Studies (Meteorology, Medical, Industrial problems)

Person of the Week

Hidetoshi Nishimori thumbnail

Self-introduction: Hidetoshi Nishimori

2019-11-13

I am a Professor at the Institute of Innovative Research, Tokyo Institute of Technology. I obtained my degrees, BSc, MSc, and DSc, from the Department of Physics of the University of Tokyo. After a stint as a postdoctoral fellow at Carnegie-Mellon University and Rutgers University in the United States, I returned to Japan and have been working at Tokyo Institute of Technology, mostly at the Physics Department but I recently moved to the Institute of Innovative Research as the head of the Quantum Computing Research Unit.

My main interest has been the theory of spin glasses, a typical hard problem of equilibrium statistical mechanics, especially exact results derived by using a special type of symmetry. I am recently more interested in quantum annealing, a quantum-mechanical paradigm to solve combinatorial optimization problems, a typical example of which is the ground-state search of spin glasses. This is a very exciting field not just because of the big attention from the society to quantum computing in general, but also due to the very interdisciplinary characteristics of the field in that very basic theoretical results are sometimes immediately implemented in real devices, typically the D-Wave quantum annealer, thus affecting the performance of the device in real-world industrial applications. I hope the stimulating environment of iTHEMS to further broaden the scope my research activities, leading to unexpected developments that are hard to be achieved elsewhere.

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