Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS) is an international research program at RIKEN. It facilitates close collaborations among researchers from different disciplines in theoretical, mathematical and computational sciences. The ultimate goal of iTHEMS is to unravel the mystery of the Universe, matter, and life, as well as to solve key problems in modern society through interdisciplinary approaches.
Upcoming Events

Seminar
Recent Progress in the Swampland Program
May 19 at 14:00  15:30, 2022
Dr. Toshifumi Noumi (Associate Professor, Institute of Cosmophysics, Department of Physics, Graduate School of Science, Kobe University)
Abstract: In the past years, it has become increasingly clear that there exist nontrivial consistency conditions on symmetries in quantum gravity, that are invisible in classical gravity. The Swampland program aims at identifying such quantum gravity constraints and their implications for particle physics and cosmology, toward quantum gravity phenomenology. In this talk, I will review recent progress in this program, including my own works.
Venue: Hybrid Format (Common Room 246248 and Zoom)
Event Official Language: English

Seminar
More Data, More Problems: Big Data in Correlative Ecology
May 19 at 16:00  17:00, 2022
Dr. Dan Warren (Staff Scientist, Biodiversity and Biocomplexity Unit, Okinawa Institute of Science and Technology Graduate University (OIST))
The rapidly expanding pool of large data sets on species distributions, community composition, and environmental factors has been accompanied by an increasing number of methodological approaches to analyze this data. If done correctly, this represents an unprecedented opportunity for understanding ecological processes at large scales. However, it also represents an opportunity to be wrong about those same processes at a scale that was previously not possible. In this talk, I will use examples from ecology and other fields to discuss some of the issues that arise when we take big data approaches to ecological questions.
Venue: via Zoom
Event Official Language: English

Seminar
Deviations from the Standard Model Predictions and New Physics Interpretations
May 20 at 13:30  15:00, 2022
Dr. Teppei Kitahara (Assistant Professor, KobayashiMaskawa Institute for the Origin of Particles and the Universe (KMI), Nagoya University)
Continuous development of experiments in recent years has revealed a large number of experimental anomalies which the Standard Model cannot explain. It is statistically obvious that as the number of experiments increases, one encounters a new anomaly due to the statistical fluctuation. But interestingly, some of the anomalies have been crosschecked by different experiments. These would be hints for physics beyond the Standard model. In this talk, I will review the flavor anomalies (also known as lepton flavor universality violation), the muon g2 anomaly, and recently measured the W boson mass anomaly. I will also discuss these implications for the new physics, and introduce several of our works.
Venue: Hybrid Format (Common Room 246248 and Zoom)
Event Official Language: English

Seminar
The Hunt for Extraterrestrial Neutrino Counterparts
May 20 at 16:00  17:00, 2022
Dr. Yannis Liodakis (Postdoctoral Researcher, University of Turku, Finland)
The origin of highenergy neutrinos is fundamental to our understanding of the Universe. Apart from the technical challenges of operating detectors deep below ice, oceans, and lakes, the phenomenological challenges are even greater. The sources are unknown, unpredictable, and we lack clear signatures. Neutrino astronomy therefore represents the greatest challenge faced by the astronomy and physics communities thus far. The possible neutrino sources range from accretion disks and tidal disruption events, through relativistic jets to galaxy clusters with blazar TXS 0506+056 the most compelling association thus far. Since then, immense effort has been put into associating AGNjets with highenergy neutrinos, but to no avail. I will discuss our current efforts in understanding the multimessenger processes in the Universe, and once and for all proving or disproving if AGNjets are neutrino emitters.
Venue: via Zoom
Event Official Language: English

Seminar
A mathematical formulation of twodimensional conformal field theory
May 23 at 14:00  16:30, 2022
Dr. Yuto Moriwaki (Special Postdoctoral Researcher, iTHEMS)
The mathematical construction of nontrivial quantum field theory in four dimensions, known as the "YangMills existence and mass gap problem", is a very important issue in mathematical sciences. There are many examples of rigorous quantum field theories in two dimensions, although the four dimensions have not yet been solved. In particular, twodimensional conformal field theory, which is a quantum field theory with conformal symmetry, has good properties and can be formulated mathematically using algebraic structures formed by "products of a field and a field" (operator product expansion). In this talk, this algebraic formulation (full vertex algebra) will be explained. Various construction methods and concrete examples (construction using codes, construction from quantum groups, and construction by deformation) will then be discussed. All the talk here is mathematical, but I will try to speak in a way that is motivated by physics as much as possible throughout the talk. I hope to receive various comments from the viewpoints of other fields.
Venue: Hybrid Format (Common Room 246248 and Zoom)
Event Official Language: English

Seminar
Introduction to Topological Insulators: The Tenfold Classification of Topological Insulators and Superconductors
May 24 at 14:00  15:30, 2022
Dr. ChingKai Chiu (Senior Research Scientist, iTHEMS)
Venue: via Zoom
Event Official Language: English

Seminar
Equilibrium or not? Mathematical differences between acute & chronic virus infections
May 25 at 13:30  15:00, 2022
Prof. Catherine Beauchemin (Deputy Program Director, iTHEMS)
The widely acclaimed 1995/1996 papers by Ho, Perelson and others [1,2] demonstrated the important insights that come from mathematical modelling of virus infection kinetics within a person. But there are key dynamical differences between chronic and acute infections, namely whether the infection reaches or maintains some equilibrium or not. In this talk, I will introduce the equations used to describe a virus infection within a person. I will show some of the tricks used by mathematical modellers to extract important rate estimates from measurements in patients infected with chronic diseases, like HIV or Hepatitis C virus. I will explain why it is difficult to extract meaningful information from measurements in patients with an acute infection, like influenza or possibly COVID19 [3]. I hope to hear from the audience if they have any thoughts about overcoming the issue to extract better rate information from limited data in patients with acute infections. (This seminar is a joint seminar between Nonequilibrium working group and Biology study group)
Venue: via Zoom
Event Official Language: English

Seminar
"TBA" by Yuki Fujimoto (University of Washington)
June 15 at 13:30  15:00, 2022
Dr. Yuki Fujimoto (Postdoctoral Scholars, Department of Physics, University of Washington, USA)
TBA
Venue: via Zoom
Event Official Language: English

Seminar
"TBA" by Sotaro Sugishita (Nagoya University)
June 22 at 13:30  15:00, 2022
Dr. Sotaro Sugishita (Designated Assistant Professor, Institute for Advanced Research (IAR), Nagoya University)
TBA
Venue: via Zoom / #246, 2F, RIKEN Wako Campus
Event Official Language: English

Seminar
Superconductinglike heat current: Effective cancellation of currentdissipation tradeoff by quantum coherence
July 25 at 13:30  15:00, 2022
Dr. Tajima Hiroyasu (Assistant Professor, Graduate School of Informatics and Engineering, The University of ElectroCommunications)
Recent developments in statistical mechanics have revealed a tradeoff between heat current and dissipation [1,2]. In various situations, this currentdissipation tradeoff represents a relationship between thermal energy flow and entropy increase, similar to Joule’s law W=RI^2. On the other hand, the coherence effect on the currentdissipation tradeoff has not been thoroughly analyzed. Here, we systematically analyze how coherence affects the currentdissipation tradeoff [3]. The results can be summarized in the following three rules:
Venue: via Zoom
Event Official Language: English

Workshop
DM3  Deep insights and Multiple strategies for Deciphering the Mystery of Dark Matter
September 15  17, 2022
Venue: SUURICOOL (Kobe) / via Zoom
Event Official Language: English
Opportunities

Seeking a Research Scientist or Senior Research Scientist (W21319) *theoretical and mathematical biology or biophysics
Deadline: Open until filled
Research Scientists or Senior Research Scientists a few positions. iTHEMS is seeking a research scientist or senior research scientist in theoretical and mathematical biology or biophysics. The successful applicant is expected not only to pursue toplevel research in mathematical science but also to lead interdisciplinary collaborations among different fields such as mathematics, physics, chemistry, biology, information sciences, computational sciences, and social sciences, under the concept of iTHEMS.

Seeking a Research Scientist or Senior Research Scientist (W21320) *mathematical sciences including pure mathematics
Deadline: Open until filled
Research Scientists or Senior Research Scientists a few positions. iTHEMS is seeking a research scientist or senior research scientist in mathematical sciences including pure mathematics, applied mathematics and information sciences. Successful applicant is expected not only to pursue toplevel research in mathematical science but also to lead interdisciplinary collaborations among different fields such as mathematics, physics, chemistry, biology, information sciences, computational sciences, and social sciences, under the concept of iTHEMS.

Seeking an Assistant (W21316) [Japanese page only]
Deadline: June 10, 2022
Latest News

20220509
Press ReleaseDiscovering Speed Limits for Macroscopic Transitions  A Unified Approach Based on the Equation of Continuity
Ryusuke Hamazaki (RIKEN Hakubi Team Leader, Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team / Senior Research Scientist, iTHEMS) has discovered a new inequality for the “speed limit," or transition rate, which is useful for physical processes that involve "macroscopic transitions". The research results are expected to have implications for nonequilibrium statistical mechanics, including the time scale of thermalization of quantum manybody systems. They are also expected to contribute to the fundamental understanding of quantum technology, e.g., the control of macroscopic quantum systems, which has become important in recent years. Please see related link for more details.

20220509
Press ReleaseClear Visualization of Lamb Waves from Tonga's Undersea Volcano Eruption The Full Picture of the Waves Captured by the Himawari8
Takemasa Miyoshi (Deputy Program Director, iTHEMS / Team Leader, Data Assimilation Research Team, RIKEN Center for Computational Science (RCCS)) and Shigenori Otsuka (Research Scientist, iTHEMS / Research Scientist, Data Assimilation Research Team, RIKEN Center for Computational Science (RCCS)) have developed an original method to clearly visualize "Lamb waves," a type of sound wave associated with Tonga's undersea volcanic eruption in January 2022, using images from the Himawari 8 meteorological satellite. Furthermore, we developed a method to automatically extract the Lamb waves from this image and clarified the relationship between the distribution of arrival times and ground pressure observations. The results of this research are expected to contribute to the scientific understanding and monitoring of atmospheric waves and associated tidal fluctuations caused by volcanic eruptions, and to the development of advanced simulations and future forecasting methods by integrating observation data with largescale atmospheric and oceanographic calculations. Please see related links for more details.

20220505
Paper of the WeekWeek 2, May 2022
Title: High energy emission component, population, and contribution to the extragalactic gammaray background of gammaray emitting radio galaxies Author: Yasushi Fukazawa, Hiroto Matake, Taishu Kayanoki, Yoshiyuki Inoue, Justin Finke arXiv: http://arxiv.org/abs/2204.14019v1 Title: The $a$points of the Riemann zetafunction and the functional equation Author: Athanasios Sourmelidis, Jörn Steuding, Ade Irma Suriajaya arXiv: http://arxiv.org/abs/2204.13887v1 Title: Speed Limits for Macroscopic Transitions Author: Ryusuke Hamazaki Journal Reference: PRX Quantum 3, 020319 (2022) doi: https://doi.org/10.1103/PRXQuantum.3.020319 arXiv: http://arxiv.org/abs/2110.09716v3
Upcoming Visitors

Visiting
Dr. Toshifumi Noumi
Associate Professor, Institute of Cosmophysics, Department of Physics, Graduate School of Science, Kobe UniversityTerm: May 17  20, 2022Visiting Place: RIKEN Wako Campus 
Tomorrow
Dr. Naomi Tsuji
Visiting Scientist, iTHEMS / Assistant Professor, Faculty of Science, Kanagawa UniversityTerm: May 18, 2022Visiting Place: RIKEN Wako Campus