iTHEMS Weekly News Letter

Upcoming Events


Number Theory Seminar

Generating functions of CM & RM values

November 22 at 10:30 - 11:30, 2018

Dr. Toshiki Matsusaka (Kyushu University)

The special values of the elliptic modular j function j(z) at imaginary quadratic points are known as singular moduli (CM values), and play important roles in algebraic number theory. As a real quadratic analogue, Kaneko (2009) defined the `values’ of j(z) at real quadratic points (RM values). In 2011, Duke-Imamoglu-Toth showed that the generating function of the traces of these CM & RM values becomes a harmonic Maass form of weight 1/2. In this talk, I shall introduce a new class called polyharmonic weak Maass forms, inspired by works of Lagarias-Rhoades on the Kronecker limit formula, and give a generalization of Duke-Imamoglu-Toth’s work for any polyharmonic weak Maass form.

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

Event Official Language: English


Number Theory Seminar

On A_2-liftings of sum formulas and Bowman-Bradley type formulas for finite multiple zeta values

November 22 at 11:40 - 12:40, 2018

Dr. Shin-ichiro Seki (Tohoku University)

Both the sum formula and Bowman-Bradley's theorem for multiple zeta values are well known. Recently, Saito and Wakabayashi proved counterparts of these two formulas for A-finite multiple zeta values. In this talk, I will explain that A_2-liftings of some parts of Saito-Wakabayashi's results have simple forms using Seki-Bernoulli numbers. The first part of this talk is a joint work with Shuji Yamamoto. The second part is a joint work with Hideki Murahara and Tomokazu Onozuka.

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

Event Official Language: English


Supported by iTHEMS

Workshop on Recent Developments of Chiral Matter and Topology

December 6 - 9, 2018

The aim of this workshop is to gather researchers of high-energy and condensed-matter physics working on chiral Matter and Topology, to exchange ideas and establish collaborations to tackle unsolved issues and carry out future extensions. The workshop expects to welcome 40-60 participants who are interested in the aforementioned topics.

Tomoki Ozawa, Tetsuo Hatsuda (RIKEN iTHEMS)
Di-Lun Yang (RIKEN Nishina Center; YITP, Kyoto)
Chang-Tse Hsieh (Kavli IPMU / ISSP, the Univ. of Tokyo)
Jiunn-Wei Chen, Guang-Yu Guo (National Taiwan Univ.)
Hsiang-Nan Li (Academia Sinica)

Venue: National Taiwan University, Taipei, Taiwan

Event Official Language: English


Number Theory Seminar

Probability density functions attached to zeta functions

December 6 at 16:00 - 17:00, 2018

Dr. Masahiro Mine (Tokyo Institute of Technology)

The study of the value-distribution of the Riemann zeta function is a classical topic in analytic number theory. In 1930s, Bohr and Jessen proved the existence of a certain limit value regarded as the probability that values of the Riemann zeta function belong to a given region in the complex plane. After Bohr and Jessen, similar results were proved for many other zeta functions. In this talk, I'll talk about density functions of such probabilities attached to the value-distributions of zeta functions. The density functions, which were named ``M-functions'' by Ihara, are connected with mean values of zeta functions, distributions of zeros of zeta functions, and so on.

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

Event Official Language: English

Special Lecture

The physical and biological basis of tissue growth

December 12 at 15:00 - 16:30, 2018

Dr. Kaoru Sugimura (Program-Specific Research Center Associate Professor, Kyoto University)
Dr. Shuji Ishihara (Project Associate Professor, The University of Tokyo)

15:00 - 15:40 "Physical and molecular mechanism of cell rearrangement" Kaoru Sugimura
15:50 - 16:30 "From cells to tissue: A continuum model of epithelial tissue mechanics" Shuji Ishihara

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

Broadcast: R511, 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: Japanese

Math Lecture

Dr. Yosuke Kubota thumbnail

Theory of Operator Algebras

Theory of Operator Algebras (6th)

December 20 at 15:30 - 17:00, 2018

Dr. 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


Computational Science Research Building venue photo

Co-hosted by iTHEMS

The 7th International Symposium on Data Assimilation (ISDA2019)

January 21 - 24, 2019

The symposium will focus on the cross-cutting issues shared in broad applications of data assimilation from geoscience to various physical and biological sciences. In particular, the symposium will enhance discussions among researchers with various background on, for example, non-Gaussian and nonlinear data assimilation problems, Big Data Assimilation (BDA), high-performance computation (HPC), Uncertainty Quantification (UQ), advanced intelligence (AI) and machine learning, multi-scale and multi-component treatments, observational issues, and mathematical problems.

Abstract Submission Deadline: October 14, 2018 at 11:59 p.m. UTC
Registration Deadline: December 16, 2018 at 11:59 p.m. UTC
Submission/Registration Fee: Free

Venue: 6F auditorium, Computational Science Research Building, R-CCS, Kobe Campus, RIKEN

Event Official Language: English


RIKEN-Berkeley WS on Quantum Information Science (RB19)

January 25 - 29, 2019

Initiated by the RIKEN Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program at Berkeley, this workshop will focus on the development of quantum computing techniques, quantum 
materials, and quantum sensing, as well as their corresponding applications to physical sciences, with an emphasis to galvanize the participants into future collaboration.

Takumi Doi (RIKEN iTHEMS)
Tetsuo Hatsuda (RIKEN iTHEMS)
Alan Poon (LBNL NSD/BQ)

Jonathan Carter (LBNL CRD/BQ)
Yasunobu Nakamura (RIKEN CEMS/Tokyo)
Franco Nori (RIKEN/Michigan)
Thomas Schenkel (LBNL AT-AP/BQ)
Irfan Siddiqi (UCB/BQ)
Seigo Tarucha (RIKEN CEMS/Tokyo)

Co-hosted by
Lawrence Berkeley National Lab. (LBNL) 
Univ. of California at Berkeley (UCB) 

Supported by
Berkeley Quantum (bq) 
US Dept. of Energy (DOE) 

Venue: Lawrence Berkeley National Laboratory (Berkeley, California)

Event Official Language: English


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

March 6 - 8, 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: by 30th November 2018.
We are looking forward to seeing you at Hokkaido U.

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

Person of the Week

Mr. Yongjia Huang thumbnail

Self-introduction: Yongjia Huang


I am Yongjia Huang, an International Program Associate (IPA) student studying in iTHEMS. My research interest is to explore what are the new states of matter at exceedingly high density and temperature. In the universe, various compact objects can reach more extreme condition than laboratory, thus they would be ideal candidates. I am studying the GRMHD simulation of binary neutron stars and neutron star-black hole mergers, which would generate various observable outcomes like gravitational wave (GW) radiation, kilonova, outflow and so on. With the GW astronomy era in progress, we would have a good chance to get the information like chirp mass and tidal deformability of the objects. Combining the GW data with the simulation works, then we can determine the equation of state of neutron stars efficiently. I am glad to have colleagues from different fields, and I believe our communication would play an important role in research.

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