iTHEMS Weekly News Letter

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SOKENDAI-iTHEMS Joint Workshop was held from July 7 to July 8


SOKENDAI-iTHEMS Joint Workshop "Genetics meets Mathematics" was held at Hayama, Kanagawa (close to SOKENDAI Hayama campus) from July 7 to July 8. This workshop brought together 36 participants, including 10 from RIKEN and 7 from SOKENDAI, of a wide variety of scientific background such as pure mathematicians, physicists, and biologists. There were lectures and talks on topics related to genetics and evolution given by biologists aimed at mathematicians and physicists without any background in biology, and those by mathematicians and physicists tackling biological problems. It was a very successful "interdisciplinary" event that provided many young mathematicians and physicists a unique opportunity to interact with biologists and vice-versa.

Upcoming Events


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iTHEMS Math Seminar

Introduction to Schroedinger Operators

July 12 at 16:00 - 18:10, 2019

Dr. Keita Mikami (Research Scientist, iTHEMS)

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.

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

Event Official Language: English


STAMP Seminar

Large scale dynamics of integrable systems

July 12 at 16:00 - 17:00, 2019

Dr. 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.

Venue: Building 14 #213, Yagami campus, Keio University

Event Official Language: English


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MACS ColloquiumSupported by iTHEMSSUURI-COOL (Kyoto)

The 9th MACS Colloquium

July 12 at 16:15 - 18:50, 2019

Prof. Makoto Fujita (Professor, Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo)
Prof. Kazutoshi Mori (Professor, Department of Biophysics, Kyoto University, Graduate School of Science)

16:15- Teatime
16:30- Talk by Prof. Makoto Fujita
17:50- Talk by Prof. Kazutoshi Mori

The 9th 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

External Event

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Interstellar Memes

July 25 at 20:00 - 21:30, 2019

Dr. Don Warren (Research Scientist, iTHEMS)

Memes are to cultures what genes are to people: ideas, behaviors, or styles that are transmitted within the culture and can propagate or die out. The universe is a big place. How much of it knows about Grumpy Cat? Tale of Genji? Earth?

Cost: JPY1,500 including a drink

Venue: Good Heavens Bar (2F 5-32-5 Daizawa, Setagaya-ku, Tokyo 155-0032)

Event Official Language: English


Co-hosted by iTHEMSSUURI-COOL (Kyoto)

RIMS-iTHEMS joint WS on "Math of Jets"

July 29 - 31, 2019

Co-hosted by RIMS Kyoto University and iTHEMS RIKEN.

Venue: Kyoto University, Main Campus Research Bldg No 15, #201

Event Official Language: Japanese


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SUURI-COOL (Kyushu) Lecture

July 31 - August 2, 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.

Venue: SUURI-COOL (Kyushu), Ito Campus, Kyushu University

Event Official Language: English


Math-Life Workshop

August 19 - 20, 2019

Masaharu Nagayama (MSC, Hokkaido Univ.)
Tetsuo Hatsuda (iTHEMS, RIKEN)
Hiroshi Suito (AIMR, Tohoku Univ.)
Takayuki Sakajyo (SACRA, Kyoto Univ.)

Venue: 1F Seminar Room, Frontier Research in Applied Sciences Building, Hokkaido Univ.

Event Official Language: Japanese

Featured Paper of the Week

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Instantons in Chiral Magnets


More than 50 years ago, Russian physicist Dzyaloshinsky has proposed the specific interaction in some kinds of magnets to explain weak ferromagnetic behavior of them, and soon after that, Professor Moriya has identified its microscopic origin as the spin-orbit coupling. That interaction, now called the Dzyaloshinskii–Moriya (DM) interaction, is one of the most important topics in both experimental and theoretical study of magnetism. This is because it induces novel inhomogeneously ordered states in spin systems such as a chiral soliton lattice and Skyrmion crystal. These interesting states support non-vanishing "topological" charges and have been experimentally observed in some magnetic materials. In this paper, focussing on one-dimensional antiferromagnetic spin chains with the DM interaction, we exhaustively construct instanton solutions with topological excitations and elucidate their properties based on the field theoretical (nonlinear sigma model) description of spin chains. As shown in Fig, the resulting spin configurations show helical ordering due to the DM interaction.

Masaru Hongo, Toshiaki Fujimori, Tatsuhiro Misumi, Muneto Nitta, Norisuke Sakai
"Instantons in Chiral Magnets"
Phys. Rev. B 101, 104417 (2020)
doi: 10.1103/PhysRevB.101.104417
arXiv: 1907.02062

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