Volume 77

iTHEMS Weekly News Letter

Announcement

Takashi Sakajo thumbnail
Hidetoshi Nishimori thumbnail

Two Senior Visiting Scientists jointed iTHEMS

2019-11-07

It is our great pleasure to announce that two Senior Visiting Scientists have joined iTHEMS from Nov.1, 2019.

Prof. Takashi Sakajo (Kyoto Univ.) whose research fields are applied mathematics and mathematical fluid dynamics.
He is in charge of the SUURI-COOL Kyoto.

Prof. Hidetoshi Nishimori (Tokyo Institute of Technology) whose research fields are statistical mechanics and quantum computation.
He is one of the founding members of the iTHEMS QCoIn working group.

Hot Topic

iTHEMS Coffee Meeting continues

2019-11-08

Every Friday, we have iTHEMS coffee meeting from 12:30, where somebody is asked to give a 15 min. lecture on a specific topic for non-experts by using our jumbo blackboard.
On Oct.25, 2019, Ivan Kostov (CEA-Saclay) gave a 15 min. lecture on integrability in quantum field theory by drawing s multi-particle scattering diagram for elementary particles living in 2 space-time dimensions.
On Nov.1, 2019, Pascal Naidon (RIKEN Nishina Center) gave a 15 min. lecture on the quantum physics of Efimov effect by using his handmade Borromean rings (three entangled ribbons which is a classical analogue of the Efimov effect).

Seminar Report

Math Seminar talks by Dr. Ken Shiozaki

2019-11-01

The iTHEMS Math seminar was held on 24 Oct., inviting Ken Shiozaki from Kyoto university. The title of the talk was "Atiyah-Hirzebruch spectral sequence in band theory". The main subject of the talk was topological K-theory, a branch of topology in mathematics, from the viewpoint of physics. In the theory of condensed matter physics, it is well-understood that a classification of topological phases is given by topological (twisted equivariant) K-theory. Conversely, some physical intuitions help us understanding (or even calculating) K-theory. In the talk, the speaker illustrated "physical meanings" of basic mathematical notions such as the axioms of cohomology theory, the Mayer-Vietoris exact sequence and the Bott periodicity.

Upcoming Events

Workshop

SUURI-COOL (Kyoto) venue photo

Collaborative Meeting on Supernova Remnants between Japan and USA

November 7 (Thu) - 12 (Tue), 2019

The aim of the workshop is to bring together experts on supernova remnants and related topics for active discussions and to initiate possible collaborations among the participants.
The workshop will be held at RIKEN Wako campus (first week, Nov. 7th and 8th) and Kyoto University (second week, Nov. 11th and 12th).

This workshop is supported by iTHEMS (RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program) and r-EMU (RIKEN Pioneering Project:Evolution of Matter in the Universe).

Venue: Okochi Hall, 1F Laser Science Laboratory, RIKEN / 224-226, Main Research Building / SUURI-COOL (Kyoto), #204-205, 2F Maskawa Building for Education and Research, North Campus, Kyoto University

Event Official Language: English

Seminar

iTHEMS Math Seminar

Some topics in projective geometry of algebraic varieties

November 8 (Fri) at 16:00 - 18:10, 2019

Atsushi Ito (Assistant Professor, Graduate School of Mathematics, Nagoya University)

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 talk about Gauss maps and projective dual varieties, which are classical objects in projective geometry of algebraic varieties.
In particular, we explain Gauss maps in positive characteristic and projective dual varieties of toric varieties in characteristic 0.

Venue: Seminar Room #160, 1F Main Research Building, RIKEN

Event Official Language: English

Lecture

RIKEN Open Campus in Kobe thumbnail
Integrated Innovation Building (IIB) venue photo

RIKEN Open Campus in Kobe

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

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), Kobe Campus, RIKEN

Event Official Language: Japanese

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

The 10th MACS Colloquium thumbnail

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

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

Upcoming Visitor

Catherine Beauchemin thumbnail

November 13 (Wed) - 27 (Wed), 2019

Catherine Beauchemin

Senior Visiting Scientist, iTHEMS / Professor, Department of Physics, Ryerson University, Canada

Research fields: Virophysics

Visiting Place: 231, Main Research Building

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