Volume 293

iTHEMS Weekly News Letter

Hot Topic

RIKEN-Nara Women's University Joint Diversity Promotion Workshop 2024 was held

2024-03-07

On February 29th and March 1st, a total of 23 students from various courses including mathematics, physics, chemistry, biology, and environmental science at Nara Women's University (2nd to 4th year undergraduates, 1st and 2nd year master's students) visited different laboratories at RIKEN: the Azuma Laboratory (CPR), the Takeishi Laboratory (CBS), iTHEMS, the RIBF facility, and the Sako Laboratory (CPR). At each laboratory, they had the opportunity to glimpse cutting-edge research, and during the evening exchange sessions with RIKEN researchers, they were able to ask deeper questions about the research topics and learn about the researchers' daily lives.

This diversity promotion activity is part of a joint initiative between the Faculty of Science at Nara Women's University and RIKEN iTHEMS, conducted in conjunction with a series of lectures at Nara Women's University, and is planned to continue in the coming years.

Upcoming Events

Seminar

DMWG Seminar

Multimessenger probes of superheavy dark matter decay and annihilation

March 26 (Tue) at 10:18 - 11:00, 2024

Saikat Das (Postdoctoral Fellows, Yukawa Institute for Theoretical Physics, Kyoto University)

We revisit constraints on decaying very heavy dark matter (VHDM) using the latest ultrahigh-energy cosmic-ray (UHECR; E >1e18 eV) data and ultrahigh-energy (UHE) gamma-ray flux upper limits, measured by the Pierre Auger Observatory. We present updated limits on the VHDM lifetime for masses up to ∼ 1e15 GeV, considering decay into quarks, leptons, and massive bosons. In particular, we consider not only the UHECR spectrum but their composition data that favors heavier nuclei. Such a combined analysis improves the limits at <1e12 GeV because VHDM decay does not produce UHECR nuclei. We also show that the constraints from the UHE gamma-ray upper limits are ∼ 10 times more stringent than that obtained from cosmic rays, for all of the Standard Model final states we consider. The latter improves our limits to VHDM lifetime by a factor of two for dark matter mass >1e12 GeV. We also provide constraints using neutrino flux from dark matter decay, including the neutrino-induced cascades. We consider the interaction of UHE neutrinos with the cosmic neutrino background, leading to the attenuation of the extragalactic flux reaching Earth, which improves our analysis to obtain tighter constraints.

Venue: via Zoom

Event Official Language: English

Special Lecture

Co-hosted by iTHEMS

Kyoto University SACRA-RIKEN iTHEMS Special Lecture by Prof. Tadashi Tokieda

March 28 (Thu) at 13:30 - 16:30, 2024

Tadashi Tokieda (Professor, Department of Mathematics, Stanford University, USA)

This event will be conducted in Japanese.

Venue: Large Conference Room, The Kyoto University Tokyo Office

Event Official Language: Japanese

Colloquium

The 25th MACS Colloquium thumbnail
Maskawa Building for Education and Research venue photo

MACS ColloquiumSupported by iTHEMS

The 25th MACS Colloquium

April 19 (Fri) at 14:45 - 18:30, 2024

Wataru Morita (Researcher, Department of Anthropology, National Museum of Nature and Science / Associate Professor, Department of Biological Sciences, Graduate School of Science, The University of Tokyo)

14:45-15:00 Teatime discussion
15:00-16:00 Talk by Dr. Wataru Morita (Researcher, Department of Anthropology, National Museum of Nature and Science / Associate Professor, Department of Biological Sciences, Graduate School of Science, The University of Tokyo)
16:15-17:20 2024 Study Group introduction session
17:30-18:30 Discussion

Venue: Maskawa Hall, 1F, Maskawa Building for Education and Research, North Campus, Kyoto University

Event Official Language: Japanese

Workshop

Recent Developments and Challenges in Topological Phases

June 3 (Mon) - 14 (Fri), 2024

Thanks to intensive research efforts, topology has been established as a fundamental concept in physics. For closed quantum systems, the classification of gapped topological phases has matured. Moreover, the importance of topology is not limited to isolated quantum systems. Recently, the topology of non-Hermitian Hamiltonians, which effectively describe systems with dissipation, has attracted much attention worldwide. This fascination is exemplified by topological phases and topological phenomena unique to non-Hermitian systems.

Against this background, the primary purpose of this workshop is to bring together researchers working on topological phases and to discuss (i) open questions in topological phases of closed quantum systems and (ii) the role of topology in open quantum systems and measurements.

Venue: Yukawa Institute for Theoretical Physics, Kyoto University

Event Official Language: English

Person of the Week

Lingxiao Wang thumbnail

Self-introduction: Lingxiao Wang

2024-03-11

Hello everyone! My name is Lingxiao Wang (王 凌霄). My research ambitiously bridges the fields of machine learning and physics, with a particular focus on using deep learning techniques, such as deep neural networks (DNNs) and generative AI, to explore QCD matter with physics models and lattice calculations. Beyond traditional boundaries, my work extends to pioneering applications of AI for Science, such as the automating scientific discovery, medical AI, and the analysis of collective behavior.

My academic journey in physics commenced with a Ph.D. at Tsinghua University, China(2015-2020), where I investigated quark matter under extreme conditions. Concurrently, I was a visiting Ph.D. student at the University of Tokyo, Japan(2018-2019), focusing on chiral matter. During my postdoctoral position at the Frankfurt Institute for Advanced Studies(FIAS), Germany (2020-2023), I honed my expertise in applying machine learning to physical sciences, and simultaneously held a joint position as a Research Assistant at Insitute of Physics in Goethe University, where I applied machine learning to THz physics. Currently, I am also a Visiting Scholar at the Institute of Modern Physics, Fudan University, China, working on machine learning applications in particle and nuclear physics.

For many years, I have organized a series of "Machine Learning Physics" seminars and learning clubs, providing an inclusive space for scientists interested in AI. I am especially enthusiastic about knowledge sharing and discussions that pave the way for interdisciplinary topics. My door (Main Building 249) is always open for anyone who wants to drink a cup of coffee/tea with me!

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