Our colleague Hiroshi Yokota has moved to the Graduate School of Human and Environmental Studies, Kyoto University as a CREST postdoctoral researcher from March 1, 2023. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Hiroshi Yokota:

I had worked at iTHEMS as a postdoctoral researcher for almost 4 years.
I would like to thank all the iTHEMS members for the valuable discussions on their researches including my own research. Moreover, in iTHEMS, I had very good opportunities to attend the exciting seminars and colloquiums which gave me brilliant ideas from the various fields: physics, biology, mathematics and information. I enjoyed the discussions, the seminars and the colloquiums in iTHEMS.
I also would like to thank all assistants who gave us the comfortable research environment.
Fortunately, I am allowed to be the visiting scientist in iTHEMS. I hope to discuss with iTHEMS members in future also.

Our colleague Naritaka Oshita will move to the Kyoto University as a Hakubi assistant professor from April 1st. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Naritaka Oshita:

I enjoyed studying gravity and black holes while being a part of iTHEMS and participating in some iTHEMS events and activities. As of the end of this March, it has been almost two years since I started my second postdoc at iTHEMS as an SPDR fellow in 2021 April. From 2023 April, I will be a Hakubi assistant professor at Kyoto University and will start my exciting new research to understand the mystery of gravity.

I enjoyed discussing with many iTHEMS members who are working on physics, biology, mathematics, (quantum) information theory, etc. I thank all faculties, researchers, and students at iTHEMS for having exciting discussions with me! iTHEMS assistants have been contributing to this group to improve the research environment at iTHEMS and they kindly helped me a lot when I needed their help and was in trouble.
I appreciate all the assistants at iTHEMS for their support and for having fun conversations!

Again, thank you to all members at iTHEMS for everything! I will still be a part of iTHEMS as a visiting researcher.
I hope I can have exciting discussions and conversations with you in the future. See you again!

Our colleague Masaki Taniguchi will move to the Kyoto University as an assistant professor from April 1st. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Masaki Taniguchi:

I'd like to thank the program director and assistants for many helpful supports over these three years and also many research members for discussing with me. I spent three years in iTHEMS as a mathematical researcher(SPDR). During the three years, I could concentrate on doing my research and communicating with researchers in other fields.
In particular, I had been attending a weekly seminar focusing on interactions between math and physics. It was a valuable experience to feel various viewpoints from physics. Also, I got a chance to give a presentation at an event of RIKEN for high school or junior high school students.
In my final year, I was chosen as a research member of a program at MSRI and spent four months at Berkeley to communicate with many researchers in my field. I could also invite several researchers to the math seminar and had good opportunities to promote research.
I appreciate a good environment in iTHEMS so that I could have these experiences. From this April, I’ll be an assistant professor at Kyoto University. But, I still have several collaborators in iTHEMS, so I’d like to continue discussing with many researchers in iTHEMS as a visiting researcher.

Our colleague Etsuko Itou will move to the Yukawa Institute for Theoretical Physics, Kyoto University as an associate professor from April 1st. We all will miss her and wish her the best of luck in her latest endeavor. Here is a message from Etsuko Itou :

I worked at iTHEMS for almost a year as a senior research scientist.
I had the opportunity to discuss researches with people from various backgrounds, go on a short trip to Kawagoe, and give presentations at interdisciplinary research meetings, which was a valuable experience for me.
I would also like to thank my assistants and PR staff for their support!
I will be a visiting scientist of iTHEMS next year. I look forward to working with you again.

On Feb.27 (Mon)-March 3 (Fri), ISCO 2023 (Interdisciplinary Science Conference in Okinawa 2023 - Physics and Mathematics meet Medical Science -) was held at OIST (Okinawa Institute of Science and Technology). The conference was co-hosted by RIKEN iTHEMS, Kavli IPMU and OIST, with 135 participants inside and outside Japan. This was the first in-person conference held in OIST after the Covid-19 pandemic. There were 28 invited talks and 9 contributed talks. From RIKEN iTHEMS, Gordon Baym, Catherine Beauchemin, Gen Kurosawa, Hiro Nagataki, Hidetoshi Nishimori, Tomoki Ozawa, and Takashi Tsuboi gave scientific talks, and Tetsuo Hatsuda gave a closing remark.

The purpose of ISCO 2023 was to bring together leading researchers in the fields of physics, astrophysics, mathematics, data science, life science, environmental science, and medical science, and to discuss the latest advancements in their respective fields. In addition to the presentations held at the OIST auditorium, a tour inside the OIST campus as well as a special lecture about Sharks by Dr. K. Sato at Churaumi Aquarium were held. Participants have intensive discussions beyond the disciplines at the plenary, poster, and lunch sessions. Some of the presentation slides can be downloaded from the ISCO 2023 webpage.

On March 7 and 8, sophomores, juniors, and seniors (16 students in total) from the Faculty of Science at Nara Women's University visited RIKEN's Kawakami Laboratory, Hou Laboratory, iTHEMS, RIBF facility, and Miyawaki Laboratory. In addition to experiencing some of the cutting-edge research at each of these laboratories, they had the opportunity to ask more in-depth questions about their research and learn about the daily lives of RIKEN researchers during a social event held in the evening of the first day of the program. It was also an opportunity for students from different courses in the Faculty of Science at Nara Women's University, including mathematics, physics, biology, and environmental chemistry, to interact with each other beyond their grade level.

This diversity promotion activity is part of the RIKEJO training program jointly promoted by the Faculty of Science at Nara Women's University and RIKEN iTHEMS, and is combined with a series of lectures at Nara Women's University, and will be continued in the next fiscal year and beyond.

Taketo Sano (Special Postdoctoral Researcher, iTHEMS) is interviewed on the RIKEN website.

RIKEN has a Special Postdoctoral Researchers Program, which allows young researchers to work independently on a research theme of their own choice and free thinking, with the aim of fostering researchers who will be active internationally. We took this opportunity to interview senior researchers and current researchers who are active in their respective fields. In this second installment, we interview Taketo Sano, a Special Postdoctoral Researcher, iTHEMS.

To read more, please see the related link.

The origin of a mysterious experimental observation in a superconductor with a magnetic impurity sitting on top of it has been revealed in a theoretical study by a RIKEN researcher and a collaborator. This could help realize a robust quantum state residing in a superconductor that may find application in quantum computers.

Superconductors conduct electricity without any resistance because electrons in them form pairs that have an energy gap. But placing a magnetic atom on top of a superconductor creates a new state in this energy gap as a result of the atom’s magnetism interacting with the superconductor’s paired electrons.

Known as the Yu–Shiba–Rusinov state, or Shiba state for short, this state has been attracting a lot of interest because it could shed light on the emergence of a special state in a topological superconductor called the Majorana zero mode, which is promising for realizing fault-tolerant quantum computing.

To read more, please visit the related link.

Ultra high-energy (UHE) cosmic rays (CRs) from distant sources interact with intergalactic radiation fields, leading to their spallation and attenuation through photo-hadronic processes. Their deflection and diffusion in large scale intergalactic magnetic fields (IGMFs), in particular those associated with Mpc-scale structures, alter the cumulative cooling and interactions of a CR ensemble to modify their spectral shape and composition observed on Earth. In this talk, Ellis Owen demonstrated the extent to which IGMFs can affect observed UHE CRs, and showed that source population models are degenerate with IGMF properties. Interpretation of observations, including the endorsement or rejection of any particular UHE CR source classes, needs careful consideration of the structural properties and evolution of IGMFs. Future observations providing tighter constraints on IGMF properties will significantly improve confidence in assessing UHE CR sources and their intrinsic CR production properties.

Reported by Shigehiro Nagataki

Title: Coupled Hénon Map, Part II: Doubly and Singly Folded Horseshoes in Four Dimensions
Author: Jizhou Li, Keisuke Fujioka, Akira Shudo
arXiv: http://arxiv.org/abs/2303.06824v1

Title: Coupled Hénon Map, Part I: Topological Horseshoes and Uniform Hyperbolicity
Author: Keisuke Fujioka, Ryota Kogawa, Jizhou Li, Akira Shudo
arXiv: http://arxiv.org/abs/2303.05769v1