iTHEMS Weekly News Letter

Press Release

Prof. Hideaki Aoyama thumbnail

Untangling the complexity of market competition in consumer goods—A complex Hilbert PCA analysis

2021-02-04

A research collaboration of Prof. Makoto Mizuno (the Faculty of Commerce, Meiji University), Prof. Hideaki Aoyama (Senior Visiting Scientist, RIKEN iTHEMS) and others has developed a new econophysics method applicable to analyze marketing data.

Seminar Report

iTHEMS Theoretical Physics Seminar by Prof. Nobutoshi Yasutake on January 28, 2021

2021-01-29

On January 28, the iTHEMS-phys seminar entitled "Many body problems from quarks to stellar evolutions" given by Prof. Nobutoshi Yasutake (Chiba Institute of Technology/JAEA) was held. He has been working for the stelar evolutions as gravitational many-body problems and the hadronic matter as quantum many-body problems based on the Lagrangian schemes. Recently, he discussed hadronic matters properties using the color molecular dynamics.

The seminar was held via the Zoom online conference systems. Around 20 people, including outside from iTHEMS, attended the seminar. The discussion was quite lively, and it was continued more than one hour even after the seminar.

Upcoming Events

Workshop

Co-hosted by iTHEMS

The 12th RIKEN-Kyoto University Joint Data Assimilation Workshop

February 10 at 13:30 - 16:30, 2021

Language: Japanese/English
Participation deadline: Tuesday, February 9, 2021

Venue: via Online

Event Official Language: Japanese

Seminar

iTHEMS Biology Seminar

A machine learning approach for prediction of mitochondrial proteins in non-model organisms

February 12 at 10:00 - 11:00, 2021

Dr. Keitaro Kume (Assistant professor, Faculty of Medicine, University of Tsukuba)

The evolution of the repertoire of proteins localized to organelles is important for understanding the evolutionary process of organelles. However, experimental methods for identifying organelle-localized proteins have been established only for model organisms and some organisms. Therefore, prediction methods using sequence data obtained from genome and transcriptome analyses, which are relatively easy to obtain, are useful. However, such prediction methods had also been established only for model organisms. In this talk, I will introduce our study in which a machine learning method was used to obtain protein candidates localized to mitochondrion-related organelles in non-model organisms.

Venue: via Zoom

Event Official Language: English

Seminar

iTHEMS Theoretical Physics Seminar

Quantum mechanical description of energy dissipation and application to heavy-ion fusion reactions

February 16 at 13:00 - 14:30, 2021

Mr. Masaaki Tokieda (Graduate students, Department of Physics, Tohoku University)

For theoretical description of heavy-ion fusion reactions, two different models have been used depending on the incident energy. At energies above the Coulomb barrier, importance of energy dissipation and fluctuation has been deduced from scattering experiments. To describe them phenomenologically, the classical Langevin equation has successfully been applied. At energies below the Coulomb barrier, on the other hand, the quantum coupled-channels method with a few number of internal states has been applied, and it has succeeded in explaining sub-barrier fusion reactions. While each method succeeds in each energy range, a unified description of heavy-ion fusion reactions from sub-barrier energies to above barrier energies is still missing. To achieve this, we need to treat dissipation and fluctuation quantum mechanically.

In order to describe dissipation and fluctuation quantum mechanically, we have applied ideas of open quantum systems to heavy-ion fusion reactions. I will talk about recent development in this talk. First I will introduce a model Hamiltonian to treat dissipation and fluctuation quantum mechanically, and explain its character and a strategy for numerical studies. I will then apply the model to a fusion problem, and discuss a role of energy dissipation during quantum tunneling. Finally I will discuss a possible future direction for a unified description of heavy-ion fusion reactions.

Venue: via Zoom

Event Official Language: English

Seminar

DMWG Seminar

Mapping the Milky Way by VLBI Astrometry

February 16 at 13:30 - 15:00, 2021

Dr. Nobuyuki Sakai (Korea Astronomy and Space Science Institute (KASI), Republic of Korea)

Astrometry is the only way to obtain 6D (position-velocity) phase space information for astronomical objects. The unique capability allows us to examine the past, present, and future of the Milky Way.
Firstly, I will introduce history and basics of astrometry. Secondly, I will overview astrometric projects in the world. Thirdly, I will highlight recent astrometric results about the Galactic structure. Lastly, I will introduce astrometric research in Korea as well as future astrometric projects and sciences in 2020s and 30s.

Venue: via Zoom

Event Official Language: English

Conference

Co-hosted by iTHEMS

Blockchain in Kyoto 2021

February 17 - 18, 2021

Language: Some parts will be in Japanese.

The International Conference on Blockchains and their Applications aims at bringing together researchers and practitioners from various communities of science and technology working on areas related to FinTech, Crypto-asset, and Blockchain.

Venue: partly online

Event Official Language: English

Colloquium

The 14th MACS Colloquium thumbnail

MACS ColloquiumSupported by iTHEMSSUURI-COOL (Kyoto)

The 14th MACS Colloquium

February 17 at 15:00 - 17:30, 2021

Prof. Yoshihiro Kaneko (Associate Professor, Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University)

15:00- Talk by Prof. Yoshihiro Kaneko
16:05- MACS Report Meeting FY2019
16:30- Discussion of each study group

Venue: via Zoom

Event Official Language: Japanese

Seminar

Prof. Gordon Baym thumbnail

ABBL-iTHEMS Joint Seminar

The Evolution of Primordial Neutrino Helicities under Gravitational and Magnetic Fields and Implications for their Detection

February 22 at 10:00 - 11:30, 2021

Prof. Gordon Baym (Senior Visiting Scientist, iTHEMS / Professor Emeritus, University of Illinois, USA)

Feb.22 (Mon) 10:00am-11:30am (JST)

Primordial neutrinos decoupled in the early universe in helicity eigenstates. As I will discuss, two effects -- dependent on neutrinos having a non-zero mass -- can modify their helicities as they propagate through the cosmos. First, finite mass neutrinos have a magnetic moment and thus their spins, but not their momenta, precess in cosmic and galactic magnetic fields. The second is the propagation of neutrinos past cosmic matter density fluctuations, which bend their momenta, and bend their spins by a smaller amount. (The latter is a general relativistic effect.) Both effects turn a fraction of left-handed neutrinos into right-handed neutrinos, and right-handed antineutrinos into left-handed. If neutrino magnetic moments approach that suggested by the XENON1T experiment as a possible explanation of their excess of low energy electron events -- a value well beyond the moment predicted by the standard model -- helicities of relic Dirac (but not Majorana) neutrinos could be considerably randomized. I finally will discuss the implications of neutrino helicity rotation, as well as their Dirac vs. Majorana nature, on their detection rates via the Inverse Tritium Beta Decay reaction.

Venue: via Online

Event Official Language: English

Paper of the Week

Week 1 of February

2021-02-04

Title: Twisted crystallograpic T-duality via the Baum--Connes isomorphism
Author: Kiyonori Gomi, Yosuke Kubota, Guo Chuan Thiang
arXiv: http://arxiv.org/abs/2102.00393v1

Title: Most charming dibaryon near unitarity
Author: Yan Lyu, Hui Tong, Takuya Sugiura, Sinya Aoki, Takumi Doi, Tetsuo Hatsuda, Jie Meng, Takaya Miyamoto
arXiv: http://arxiv.org/abs/2102.00181v1

Title: Time to revisit the endpoint dilution assay and to replace TCID50 and PFU as measures of a virus sample's infection concentration
Author: Daniel Cresta, Donald C. Warren, Christian Quirouette, Amanda P. Smith, Lindey C. Lane, Amber M. Smith, Catherine A. A. Beauchemin
arXiv: http://arxiv.org/abs/2101.11526v1

Person of the Week

Dr. Björn Victor Ahlgren thumbnail

Self-introduction: Björn Ahlgren

2021-02-04

My name is Björn Ahlgren. I joined iTHEMS as a visiting scientist in February 2021 as part of my current postdok, and I'm otherwise based at KTH in Stockholm, Sweden. My field of research is astrophysics, where I work mainly on gamma-ray bursts (GRBs), which are some of the most violent explosions in the Universe. These phenomena are caused by the collapse of particularly massive stars, and by compact object binary mergers, and they can serve both as laboratories for physics under extreme conditions, as well as probes of the early Universe. In my research I focus on the intersection between theory and observations, where I try to develop and reconcile theoretical models for the emission mechanisms of GRBs with the best available observations, using statistical methods. My specialisation lying in applied statistics, I really enjoy interdisciplinary projects where I get to work with new ideas and new data. I'm excited to join iTHEMS and I hope I will get the opportunity to engage in new collaborations across different disciplines.

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