# Research News

## Susumu Inoue (iTHEMS Research Scientist) was highlighted in a recent article of RIKEN RESEARCH "Highly energetic neutrino traced back to a blazar"

2018-11-08

"The spectrum measured by MAGIC strongly points to the neutrino being generated by a high-energy proton in the blazar’s jet interacting with low-energy photons,” says Susumu Inoue of RIKEN’s Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS) program, who is part of the MAGIC team.

# Upcoming Events

## Seminar

### The 28th QCD Club

November 9 at 15:00 - 17:00, 2018

Title: Application of a gradient flow method to thermodynamics of QCD with dynamical quarks

Language: Japanese or English

Event Official Language: English

## External Event

### Nerd Nite Tokyo

November 9 at 20:00 - 22:00, 2018

Dr. Ade Irma Suriajaya (Special Postdoctoral Researcher, iTHEMS)

Chacha will tell us about infinities, some bad math, and some good math.

Price: ¥1000, but speakers get in free

Food and drinks available at the event

Venue: Nagatacho GRID (2-5-3 Hirakawa-cho, Chiyoda-ku, Tokyo 102-0093)

Event Official Language: English

## Seminar

### ABBL-iTHEMS Joint Seminar 1

November 12 at 14:00 - 15:00, 2018

Dr. Volodymyr Takhistov

Title: New Venues in Formation and Detection of Primordial Black Hole Dark Matter

Abstract: Primordial black holes (PBH) provide an attractive non-particle dark matter (DM) candidate. I will discuss a novel PBH production mechanism that can appear generically in models with scalar fields. Recent re-evaluations of PBH constraints suggest that the open parameter space for PBHs to constitute all of dark matter is appreciably larger than previously thought. I will show how compact stars can serve as laboratories for probing it. The variety of resulting novel astrophysical signals are of particular interest to the vibrant field of multi-messenger astronomy. More-so, PBH-star interactions suggest an elegant resolution to some of the most puzzling questions in astrophysics, such as the origin of gold and other heavy elements.

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

Event Official Language: English

## Seminar

### Spintronics in Non-Inertial Frames

November 15 at 13:00 - 18:00, 2018

Prof. Mamoru Matsuo (University of Chinese Academy of Sciences, China)

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

Event Official Language: Japanese

## 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

## 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

## Workshop

### 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.

Organizers:

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

## 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

### 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

## Conference

### 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

# Featured Paper of the Week

## Effective field theory of time-translational symmetry breaking in nonequilibrium open system

2018-11-02

Although we know "all things are in a state of flux. (Patna rhei.)", it has been still an interesting question whether we have "universal" features in such time-evolution of all things. Considering the non-equilibrium open systems like the Brownian particles, we have tackled this problem from the point of view of time-translational symmetry. We regard the transient diffusive (or time-oscillating) behaviors as "symmetry-broken phases of matter", and develop a way to describe their spacetime evolution. Our formalism is based on the so-called effective field theory (EFT) originally developed in the context of particle physics and now used in almost every branches of physics. The advantage of the EFT is that it enables us to capture the possible universal properties in the large-scale (low-energy) behaviors of systems. As a result, we find the existence of the Nambu-Goldstone-like mode during transient time-evolution, which gives the universal diffusive behaviors of all things in a state of flux.

Reference:

Masaru Hongo, Suro Kim, Toshifumi Noumi, Atsuhisa Ota

"Effective field theory of time-translational symmetry breaking in nonequilibrium open system"

doi: 10.1007/JHEP02(2019)131

arXiv: 1805.06240

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