Volume 38

iTHEMS Weekly News Letter

Upcoming Events

Math Lecture

Introduction to Public-Key Cryptography

Introduction to Public-Key Cryptography (8th)

February 7 (Thu) at 13:30 - 15:00, 2019

Eren Mehmet Kıral (Visiting Scientist, iTHEMS / Visiting Scientist (JSPS Research Fellow), Faculty of Science and Technology, Sophia University)

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

Event Official Language: English

Colloquium

The 7th MACS Colloquium thumbnail

MACS ColloquiumSupported by iTHEMSSUURI-COOL (Kyoto)

The 7th MACS Colloquium

February 7 (Thu) at 15:00 - 17:30, 2019

Akira Tsuchiyama (Professor, Division of Earth and Planetary Sciences, Graduate School of Science/Faculty of Science, Kyoto University)

15:00- Teatime
15:15- MACS Report Meeting FY2018
16:40- Talk by Prof. Akira Tsuchiyama

The 7th MACS colloquium is 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 confectionary at Kyoto!

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

Event Official Language: Japanese

Colloquium

iTHEMS Colloquium

Tropical Rain Forest

February 21 (Thu) at 15:30 - 17:00, 2019

Akiko Satake (Professor, Mathematical Biology Laboratory, Department of Biology, Faculty of Science, Kyushu University)

In a unique phenomenon restricted to the tropical rain forests in Southeast Asia, hundreds of plant species from dozens of families reproduce synchronously at irregular, multi-year intervals. Although several hypotheses have been proposed, the proximate environmental cues that synchronize these general flowering events are uncertain. Fortunately, accumulation of long-term data and advanced statistical and modeling techniques are starting to shed new light on phenology of tropical plants. In this talk, series of studies that integrate long-term field monitoring, gene expression analyses, and modeling will be presented.

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

Broadcast: #311, Computational Science Research Building, R-CCS, Kobe Campus, RIKEN / SUURI-COOL (Kyoto), #204-205, 2F Maskawa Building for Education and Research, North Campus, Kyoto University / SUURI-COOL (Sendai), #303, 3F AIMR Main Building, Advanced Institute for Materials Research (AIMR), Tohoku University

Event Official Language: English

Math Lecture

Theory of Operator Algebras

Theory of Operator Algebras (8th)

March 5 (Tue) at 14:00 - 15:00, 2019

Yosuke Kubota (Research Scientist, iTHEMS)

Title: An introduction to operator algebras

Abstract: Operators are linear maps from a (usually an infinite dimensional) linear space (most frequently the Hilbert space) to itself, which is like matrices of infinite degree. Operators form an algebra by obvious addition and multiplication. Operators appear in most of the fields in mathematics, in algebra, in geometry, in analysis, ... Some of the key words at the beginning of these lectures are "spectral theory" "operator algebras" "Tomita-Takesaki theory". These lectures are for non-professional people.

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

Event Official Language: Japanese

Math Lecture

Theory of Operator Algebras

Theory of Operator Algebras (9th)

March 5 (Tue) at 15:30 - 16:30, 2019

Yosuke Kubota (Research Scientist, iTHEMS)

Title: An introduction to operator algebras

Abstract: Operators are linear maps from a (usually an infinite dimensional) linear space (most frequently the Hilbert space) to itself, which is like matrices of infinite degree. Operators form an algebra by obvious addition and multiplication. Operators appear in most of the fields in mathematics, in algebra, in geometry, in analysis, ... Some of the key words at the beginning of these lectures are "spectral theory" "operator algebras" "Tomita-Takesaki theory". These lectures are for non-professional people.

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

Event Official Language: Japanese

Workshop

Workshop of Nuclear-Astrophysics by UKAKUREN/Japan Forum of Nuclear Astrophysics (JaFNA): Nuclear data & Heavy Element Nucleosynthesis

March 6 (Wed) - 8 (Fri), 2019

We are pleased to announce that we will have a meeting on Nuclear-Astrophysics at Hokkaido Univ. Especially this time we will focus on the impact of nuclear data & nucleosynthesis of heavy elements. Gravitational wave is another keyword.

This workshop is held by UKAKUREN (JaFNA), together with Nuclear Reaction Data Centre, Hokkaido University (JCPRG). This workshop is supported by iTHEMS, CNS, RCNP, NAOJ, KEK, and WNSC.

You are welcomed to join us. For registration, please fill in the attached form (in Japanese) and send it to: sec-ukakuren18@kek.jp by 30th November 2018.
We are looking forward to seeing you at Hokkaido U.

Organizers
T. Kajino (Chair), T. Kawabata (Osaka), H. Utsunomiya (Konan), S. Nishimura (RIKEN), H. Yamaguchi (CNS), T.Hayakawa (QST), T.Motobayashi (RIKEN),
K.Terada(Osaka), S.Nagataki(RIKEN), S.Chiba(TIT), T.Tamagawa(RIKEN), W.Aoki(NAOJ), S.Wanajo(AEI), S.Kubono(RIKEN), T.Shima(RCNP)

Venue: Hokkaido University Conference Hall

Event Official Language: Japanese

Colloquium

iTHEMS Colloquium

ZetaValue2019-iTHEMS Special Mathematics Colloquium

March 21 (Thu) at 14:00 - 17:30, 2019

Kohji Matsumoto (Professor, Nagoya University)
Jörn Steuding (University of Würzburg, Germany)

Prof. Kohji Matsumoto (Nagoya University)
"An overview of the theory of multiple zeta-functions"
Multiple zeta-functions are generalizations of the Riemann zeta-function, and its theory has been rapidly developed in these decades. It is connected with various fields of mathematics and mathematical physics. In this talk I will give an overview of some part of recent developments, mainly from the analytic viewpoint.

Prof. Jörn Steuding (University of Würzburg, Germany)
"On the Infinite in Number Theory"
Beginning with two simple examples from elementary number theory (one of diophantine origin and one of arithmetical nature), we discuss the role of “infinity” in number theory. We touch upon topics like how to find good rational approximations to irrational quantities and the distribution of prime numbers. We conclude with a motivation of the big open question in this field, namely, the Riemann hypothesis (one of the six unsolved millennium problems) and the Langlands program.

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

Event Official Language: English

Workshop

Value distribution of zeta and L-functions and related topics thumbnail

Value distribution of zeta and L-functions and related topics

March 22 (Fri) - 27 (Wed), 2019

March 22–26, 2019
Main Conference (invited talks, posters and a limited number of short contributed talks)

Welcome Reception: March 22, 2019 (18:00~20:00)
Conference Dinner: March 25, 2019 (18:30~21:00)

March 27, 2019 (9:30~17:00)
One-day Workshop (a series of short contributed talks by young researchers to facilitate active discussions)

ORGANIZING COMMITTEE
Ade Irma Suriajaya (RIKEN)
Yoshinosuke Hirakawa (Keio University)
Masataka Ono (Kyushu University)
Shin-ichiro Seki (Tohoku University)
Keiju Sono (Ehime University)
Shingo Sugiyama (Nihon University)
Yuta Suzuki (Nagoya University)

ADVISORY COMMITTEE
Tetsuo Hatsuda (RIKEN iTHEMS)
Kenichi Bannai (Keio University, RIKEN AIP Center)

Venue: Okochi Hall, 1F Laser Science Laboratory, RIKEN / Large Meeting Room, 2F Welfare and Conference Building (Cafeteria), RIKEN

Event Official Language: English

School

AIMR Main Building venue photo

g-RIPS Sendai 2019

June 17 (Mon) - August 9 (Fri), 2019

GRIPS (Graduate-level Research in Industrial Projects for Students)-Sendai program was held last summer (June 18 - Aug. 10, 2018) with the support of iTHEMS as well as other institutions and companies. Two industrial projects were launched under the suggestion of TOYOTA and NEC, and two teams composed of US and Japanese students have worked intensively to find solutions of these problems. See for the details of the GRIPS program and the summary of activities at GRIPS-Sendai 2018.

This year, GRIPS-Sendai program will be held from June 17 through Aug. 9, 2019 with a larger scale under the support of iTHEMS. Stay tuned for further information.

Venue: 4F Research Space, AIMR Main Building, Advanced Institute for Materials Research (AIMR), Tohoku University

Event Official Language: English

Featured Paper of the Week

Index theory and topological phases of aperiodic lattices thumbnail
Christopher Bourne thumbnail

Index theory and topological phases of aperiodic lattices

2019-01-22

The paper studies the interactions between dynamical systems, represented via groupoid operator algebras, and index theory, described using Kasparov's bivariant K-functor. The key motivating example is the dynamical systems associated to Delone sets.

Delone sets give a model of aperiodic atomic configurations, where the material may be amorphous or quasi-crystalline. The atomic configuration does not have a group structure, but key properties can be encoded in a discrete groupoid. We construct bivariant K-cycles, a generalisation of K-theory classes, that encode the dynamics of the aperiodic lattice. For the case of quasi-crystalline configurations, we obtain finer information coming from the long-range aperiodic order of the material.

We then use our constructed K-cycles to define bulk topological phases of aperiodic materials. A bulk-boundary correspondence is also shown, which arises from factorisation properties of the constructed K-cycles.

Reference:
Chris Bourne, Bram Mesland
"Index theory and topological phases of aperiodic lattices"
Ann. Henri Poincare 20 (6) (2019), 1969--2038
doi: 10.1007/s00023-019-00764-9
arXiv: 1807.03972

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