RIKEN Interdisciplinary Theoretical and
Mathematical Sciences Program

Featured articles on iTHEMS published in "Sugaku Tsushin"

iTHEMS was featured in the August volume of "Sugaku Tsushin" (Japanese magazine published by The Mathematical Society of Japan). Our colleagues, Tetsuo Hatsuda, Ade Irma Suriajaya, Yosuke Kubota, Hiroyasu Miyazaki and Yukimi Goto, have written essays on iTHEMS in the volume. Let's see mathematicians' thoughts on the iTHEMS atmosphere.

2022-08-30

Is it possible to shorten isolation of people infected with new coronavirus? -Development of a simulator to verify the timing of quarantine termination

Professor Shingo Iwami (Graduate School of Science, Nagoya University / Visiting Scientist, iTHEMS), in collaboration with Assistant Professor Keisuke Ejima (Indiana University, USA), has developed a new simulator (computer simulation) to verify when to end isolation of persons infected with a novel coronavirus (COVID-19) through antigen testing. This will allow us to propose a flexible and safe isolation strategy that can terminate isolation of COVID-19-infected patients as early as possible with negative results of a predetermined number of antigen tests. Isolation of infected patients is an important means of preventing the spread of infection. While prolonged isolation reduces the risk of secondary infection, it also places various burdens on the person being isolated and the society that supports them. Using the simulator they have developed, the research group has successfully calculated "the risk of (prematurely) terminating isolation of infectious patients" and "the duration of unnecessary isolation of patients who are no longer infectious (the burden associated with isolation)." As a result, we are now able to propose an appropriate isolation strategy that takes into account individual differences and uses antigen testing to simultaneously reduce risk and burden. As we enter the era of with-colonization, in which social activities are resumed and maintained while infection prevention measures are thoroughly implemented, the successful use of antigen testing will allow for the safe implementation of educational and social activities. In contrast to the current situation where different isolation standards based on clinical and epidemiological data and empirical rules are adopted in different countries, this study is expected to contribute to the establishment of flexible isolation guidelines based on mathematical models, which are required not only in Japan but also worldwide. For more details, please visit the Nagoya University research results dissemination site from the related link.

2022-08-29

RIKEN Research: Applying quantum speed limits to macroscopic systems

An expression for the maximum speed at which changes in macroscopic systems can occur has been derived by a theoretical physicist at RIKEN. This will deepen our understanding of quantum phenomena in systems that are not in equilibrium. One of the hardest aspects of quantum mechanics to grasp is the Heisenberg uncertainty principle that states that it is not possible to simultaneously pin down both the position and momentum of an object. In other words, the more precisely a particle’s position is determined, the broader the range of its possible momentum becomes (and vice versa). In 1945, two physicists, Leonid Mandelstam and Igor Tamm, focused on another type of the uncertainty relation, namely one between time and energy fluctuation, and showed that transitions in quantum systems don’t happen instantaneously; rather, the speed at which a transition occurs is capped by an amount determined by how much the energy of the system fluctuates. Many other so-called quantum speed limits have subsequently been derived, which have helped better understand the physics of quantum systems and have been useful in various quantum applications. But big problems arise when quantum speed limits are applied to macroscopic systems. “Previous quantum speed limits, which are useful for small systems, typically become meaningless for macroscopic transitions,” notes Ryusuke Hamazaki of the Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team. “For example, conventional quantum speed limits give an infinite upper bound for the speed of transitions in a gas made up of atoms.” To read more, please visit the related link.

2022-08-26

Oita STEM Festa was held at Oita City

The Oita STEM Festa was held on 23 July 2022 at Oita city and Tetsuo Hatsuda from iTHEMS participated together with members from ADK Corporation. More than 50 high school students from Oita prefecture participated in Course B: "Let's deliver a message 1000 years from now using a black hole recorder” where the black hole recorder produced by the Useless Prototyping Studio was demonstrated. Also, the students were asked to write their Haiku to be recorderd in the black hole recorder. Over 150 high school students participated in the Oita STEM Festa. Course A: "Let's experience the lunar rover!, Course B: "Let's send a message 1000 years from now using a black hole recorder", Course C: "VR technology x solving social issues x SDGs", and Course D: "Let's think about jobs for Oita's future". iTHEMS was represented by Tetsuo Hatsuda and assistants Hitomi Wada and Chikako Ota contributed to the organisation of Course B on site.

2022-08-22

The book “An introduction to deep learning” written by Dr. Masato Taki was recently featured in the column “La Toccata” by Dr. T. Otsuki

Dr. Masato Taki (iTHEMS Visiting Research Scientist/ Rikkyo University) wrote the book “An introduction to deep learning” while he was at iTHEMS. The book was recently featured in the column “La Toccata” by Dr. T. Otsuki (Sophia University) in the journal BUTSURI published by the Physical Society of Japan in Aug. 2022. The features of this textbook are: 1. it understands what readers with a physics background will find difficult; 2. the examples are neither too simple nor too obvious so that the reader feels he/she understands by reading the examples; 3. the volume is reasonable; 4. each section is divided into small sections so that it is suitable for the reading club, and 5. the appendices are also very informative. Recommended for those who want to learn deep learning from scratch and for those who want to organize a reading club.

2022-08-18

iTHEMS Science Outreach Workshop 2022 was held on July 29-31, 2022

On July 29-31, we had Meeting on Outreach of RIKEN iTHEMS 2022 @Kobe & Zoom. This year the meeting was hosted by Suuri Cool Kobe and the venue was the auditorium (8F) + the cafeteria (6F) of Kobe Integrated Innovation Building (IIB). This meeting was hit by the big growth of infected population by Covid-19 omicron BA.5. However, under careful preparation and precaution taken, 27 people participated at Kobe IIB and 24 more by zoom. There were 11 talks at the venue and 6 talks by zoom. 4 talks were by members of iTHEMS explaining recent development in various fields in sciences. 3 talkes were from universities on different aspects of research or fostering young researchers. 10 talks were given by journalists. There were also 3 posters (2 on research and 1 on a monthly academic magazine), in addition, the Black Hole Reacorder was exhibited at the cafeteria. The participants consist of 9+10 members from RIKEN, 6+4 from universities and 12+10 journalists (at venue + by zoom). By the success of this meeting, we hope the continuation of Journalist in residence program and this workshop next year.

2022-08-08

iTHEMS and RIKEN-Berkeley Center is featured in RIKEN at a Glance 2022

RIKEN's pamphlet "RIKEN at a Glance 2022" features iTHEMS and the newly opened RIKEN-Berkeley Center. Please see the related link for details.

2022-07-26

RIKEN Research: Flitting between the wings of a butterfly

Just making small tweaks to certain variables could potentially modify extreme weather events such as sudden downpours, computer simula- tions by two RIKEN researchers have shown. Scientists have long desired to develop ways to control the weather. Research in this area has intensified due to climate change, which is giving rise to more extreme weather events. Present methods for modifying the weather have limited success. Seeding the atmosphere can induce rain, but only when the atmosphere is already in a state where it might rain. Geoen- gineering projects have been envisioned, but they have yet to be conducted due to concerns about unpredicted long-term effects. As a promising approach, Takemasa Miyoshi and Qiwen Sun, both of the RIKEN Center for Computational Science, have looked to chaos theory to assess the possibility of mitigating weather events such as torrential rain by making small changes. Instead of con- sidering the weather system in all its complexity, they focused on a far simpler system—the butterfly attractor. To read more, please see related links.

2022-06-28

RIKEN Research: Worming out of the black-hole information paradox

RIKEN physicist and two colleagues have found that a wormhole—a theoretical bridge connecting distant regions of the Universe—may help to shed light on the mystery of what happens to information about matter consumed by black holes. Einstein’s theory of general relativity predicts that nothing that falls into a black hole can escape its clutches. But in the 1970s, Stephen Hawking calculated that black holes should emit radiation when quantum mechanics, the theory governing the microscopic realm, is considered. “This is called black hole evaporation because the black hole shrinks, just like an evaporating water droplet,” explains Kanato Goto of the RIKEN Interdisciplinary Theoretical and Mathematical Sciences. To read more, please see related links.

2022-06-28

RIKEN-Berkeley Center was opened

RIKEN iTHEMS and N3AS Physics Frontier Center have started a joint research center, RIKEN-Berkeley Center (RBC), physically located on the 3rd floor of the physics building in Univ. California, Berkeley. This new Center aims to enhance the collaboration on nuclear astrophysics and quantum information science between the two institutions. On May 27-29, 2022, the first annual meeting of N3AS was held in Berkeley together with their international partners, RIKEN iTHEMS and CNRS Centre Pierre Binetruy. iTHEMS members are encouraged to use RBC as a base to interact with researchers in physics, mathematics, biology and related fields at Berkeley.

2022-06-09

What about climate change in actuality?

Odd couples of interdisciplinary research

Khovanov homology theory - an introduction to categorification by Dr. Taketo Sano on May 13, 2022

Fundamentals Fest, mini Pre-event on Science "Exploring and Bridging: The Potential of Basic Science"

In Search of Pc pentaquark - Simulate Hadron Interactions with FUGAKU

AAS Journal Author Series: Hirotaka Ito on 2021ApJ…918...59I

Will Useless Knowledge Change the Future? - What is the Black Hole Recorder?

RIKEN 2019 (in Japanese)

Area law of entanglement entropy in quantum many body systems and its implication in tensor network calculation

Comparison between conventional computers and quantum computers

A glimpse of enumerative geometry

Message-passing algorithms for graphical models