News
12 news in 2025
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2025-01-30
Paper of the WeekWeek 5, January 2025
Title: $Λ$(1405) in the flavor SU(3) limit using a separable potential in the HAL QCD method Author: Kotaro Murakami, Sinya Aoki arXiv: http://arxiv.org/abs/2501.17423v1 Title: Multi-Messenger and Cosmological Constraints on Dark Matter through Two-Fluid Neutron Star Modeling Author: Ankit Kumar, Sudhakantha Girmohanta, Hajime Sotani arXiv: http://arxiv.org/abs/2501.16829v1 Title: Left-hand cut and the HAL QCD method Author: Sinya Aoki, Takumi Doi, Yan Lyu arXiv: http://arxiv.org/abs/2501.16804v1 Title: Reconstruction of QCD first-order phase transition from neutron star measurements Author: Ronghao Li, Sophia Han, Zidu Lin, Lingxiao Wang, Kai Zhou, Shuzhe Shi arXiv: http://arxiv.org/abs/2501.15810v1 Title: Synthesis of a semimetallic Weyl ferromagnet with point Fermi surface Author: Ilya Belopolski, Ryota Watanabe, Yuki Sato, Ryutaro Yoshimi, Minoru Kawamura, Soma Nagahama, Yilin Zhao, Sen Shao, Yuanjun Jin, Yoshihiro Kato, Yoshihiro Okamura, Xiao-Xiao Zhang, Yukako Fujishiro, Youtarou Takahashi, Max Hirschberger, Atsushi Tsukazaki, Kei S. Takahashi, Ching-Kai Chiu, Guoqing Chang, Masashi Kawasaki, Naoto Nagaosa, Yoshinori Tokura Journal Reference: Nature (2025) doi: https://doi.org/10.1038/s41586-024-08330-y Title: Grassmann Tensor Renormalization Group for two-flavor massive Schwinger model with a theta term Author: Hayato Kanno, Shinichiro Akiyama, Kotaro Murakami, Shinji Takeda arXiv: http://arxiv.org/abs/2501.14086v1 Title: Pair Correlation of Zeros of the Riemann Zeta Function I: Proportions of Simple Zeros and Critical Zeros Author: Siegfred Alan C. Baluyot, Daniel Alan Goldston, Ade Irma Suriajaya, Caroline L. Turnage-Butterbaugh arXiv: http://arxiv.org/abs/2501.14545v1
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2025-01-29
Press Release
Make it worth Weyl: engineering the first semimetallic Weyl quantum crystal
An international research team, including Ching-Kai Chiu (Senior Research Scientist, iTHEMS) and led by the Strong Correlation Quantum Transport Laboratory of the RIKEN Center for Emergent Matter Science (CEMS) has achieved a world-first by realizing an ideal Weyl semimetal, marking a major breakthrough in quantum materials research. Weyl fermions emerge as quantum excitations of electrons in crystals and are predicted to exhibit exotic electromagnetic properties. However, previous Weyl materials were often overshadowed by unwanted electronic states, making it difficult to observe pure Weyl fermion behavior. The team successfully engineered an ideal Weyl semimetal by precisely controlling the composition of the topological semiconductor (Cr,Bi)2Te3, eliminating irrelevant electronic states. Published in Nature, this work opens new possibilities for terahertz (THz) light devices and next-generation electronics. For more details, please refer to the related link.
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2025-01-28
Award
Lingxiao Wang received the “Best ‘Physics for AI’ Paper Award”
Our colleague Lingxiao Wang (Research Scientist, iTHEMS) has received the “Best ‘Physics for AI’ Paper Award” of the Machine Learning and the Physical Sciences Workshop. The winning paper is entitled “Higher-order cumulants in diffusion models”. Congratulations, Lingxiao!
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2025-01-24
Hot Topic
Farewell message from Liang Zhang
Our colleague, Liang Zhang, has returned to the Shanghai Institute of Applied Physics at the University of Chinese Academy of Sciences to complete his PhD thesis. We will all miss him and wish him the very best of luck in successfully defending his thesis ! Here is a message from Liang Zhang: I joined iTHEMS in January 2023 as a joint student and completed my two-year journey here in January 2025. I initially joined iTHEMS to study lattice QCD and the HAL QCD method, and I am deeply grateful to Hatsuda-san and Doi-san for guiding me into this fascinating field. However, I soon realized that my experience at iTHEMS extended far beyond my original purpose. For example I had a discussion with Namba san on chiral symmetry breaking which is studied in both particle physics and cosmology. It left an immediate impression that physics is so universal other than reading such sentences in textbooks. And the interdisciplinary energy at iTHEMS constantly amazed me. When I first came here I always struggled to pinpoint people’s major. In some seminars, theoretical physicists gave a biology talk (like Christy)! I vaguely feel like there is a group theory for nature which can be expressed to different representations, biological, mathematical, physical, etc. Is this what the “i” in iTHEMS means? At last I would like to thank everyone in iTHEMS again for my two-year experience here. This experience gives me a great impulse to expand the possibilities of my future research life. iTHEMS’s uniqueness lies in its boundless possibilities. And I dearly hope our paths will cross again!
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2025-01-23
Paper of the WeekWeek 4, January 2025
Title: Numerical simulation of fractional topological charge in $SU(N)$ gauge theory coupled with $\mathbb{Z}_N$ 2-form gauge fields Author: Motokazu Abe, Okuto Morikawa arXiv: http://arxiv.org/abs/2501.11438v1 Title: On the connected sums of the $(2,1)$-cable of the figure eight knot Author: Yoshihiro Fukumoto, Masaki Taniguchi arXiv: http://arxiv.org/abs/2501.07910v1 Title: Lifetime measurement of the muonic atom of enriched Si isotopes Author: R. Mizuno, M. Niikura, S. Akamatsu, T. Fujiie, K. Ishida, T. Ito, T. Kikuchi, T. Matsuzaki, F. Minato, J. Murata, T. Naito, K. Shimomura, S. Takeshita, I. Umegaki, Y. Yamaguchi arXiv: http://arxiv.org/abs/2501.05897v1 Title: On the slice-torus invariant $q_M$ from $\mathbb{Z}_2$-equivariant Seiberg--Witten Floer cohomology Author: Nobuo Iida, Taketo Sano, Kouki Sato, Masaki Taniguchi arXiv: http://arxiv.org/abs/2501.07788v1 Title: Tridiagonal Hamiltonians modeling the density of states of the Double-Scaled SYK model Author: Pratik Nandy Journal Reference: JHEP 01 (2025) 072 doi: https://doi.org/10.1007/JHEP01(2025)072 arXiv: http://arxiv.org/abs/2410.07847v2
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2025-01-17
Hot Topic
Farewell message from Lucy McNeill
Our colleague Lucy McNeill has moved on to a new career as a Hakubi Assistant Professor at The Hakubi Center for Advanced Research, Kyoto University as of January 16, 2025. We all will miss her and wish her the best of luck in her latest endeavor. Here is a message from Lucy McNeill: During my 1 year at iTHEMS as a postdoctoral researcher, I was presented with opportunities to further both my own research and professional development at every turn. I am especially grateful for iTHEMS directors and colleagues' support in starting the "asymptotics in astrophysics" iTHEMS study group, ample chances to travel abroad to share my work, and the frequent international workshops organised at iTHEMS. In particular, workshops co-hosted with RIKEN-Berkeley left this lasting impression on me; that new stellar astrophysics and supernova physics paradigms are creatively and efficiently conceived when physicists, mathematicians and data scientists join forces to solve longstanding astrophysical puzzles. iTHEMS is such a special place where those necessary first interactions are regularly facilitated, and I am sad to leave. But... "I'll be back"!
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2025-01-16
Paper of the WeekWeek 3, January 2025
Title: Direct Monte Carlo computation of the 't~Hooft partition function Author: Okuto Morikawa, Hiroshi Suzuki arXiv: http://arxiv.org/abs/2501.07042v1 Title: Impact of dark matter distribution on neutron star properties Author: Ankit Kumar, Hajime Sotani arXiv: http://arxiv.org/abs/2501.07052v1 Title: Physics-Driven Learning for Inverse Problems in Quantum Chromodynamics Author: Gert Aarts, Kenji Fukushima, Tetsuo Hatsuda, Andreas Ipp, Shuzhe Shi, Lingxiao Wang, Kai Zhou Journal Reference: Nature Reviews Physics (2025) doi: https://doi.org/10.1038/s42254-024-00798-x arXiv: http://arxiv.org/abs/2501.05580v1
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2025-01-10
Hot Topic
Farewell message from Yantao Wu
Our colleague Yantao Wu will move on to a new career as a faculty member at Institute of Physics, Chinese Academy of Sciences as of January 10, 2025. We all will miss him and wish him the best of luck in his latest endeavor. Here is a message from Yantao Wu: I joined iTHEMS in June 2021 as a RIKEN-Berkeley fellow, and have stayed here for three years and a half now. iTHEMS is a precious rare place in the academic world, where there seems to be no responsibility, no one telling you what to do, and infinite space for travel; where there seems to be a curious mind on every subject and every question ought to be asked. The interdisciplinary nature of the group has forever left an imprint on me, and I will always remember the vivid biological facts and mathematical tricks that I have learned here. Entering as a condensed matter physicist and leaving as a condensed matter physicist, my heart will always have a spot for the particle theory which I have learned from here. It has been an unexpected, yet very pleasant mix. Sadly, it appears that every gathering ends somewhere, and I need to leave this warm and protective bubble to a new place, to really enter the grown world of independent research and start my own group. iTHEMS will always remain as a source of lasting encouragement. I will move to the Institute of Physics, Chinese Academy of Sciences in Beijing to start a faculty position. If you ever want to visit, please let me know you are from iTHEMS and I will make you a cup of tea (amidst taking you to the great wall and covering your travel costs.)
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2025-01-10
Press Release
Discovery of Measurement-Induced Spectral Phase Transition in Quantum Systems
A collaborative research team, including Ryusuke Hamazaki (Senior Research Scientist, iTHEMS / RIKEN Hakubi Team Leader, Nonequilibrium Quantum Statistical Mechanics RIKEN Hakubi Research Team, RIKEN Cluster for Pioneering Research (CPR)), has discovered a spectral phase transition in quantum systems under measurement. This research is expected to bridge the gap between two seemingly distinct phenomena: the recently emerging field of “measurement-induced phase transitions in nonequilibrium quantum systems" and the long-studied "phase transitions in equilibrium quantum systems." By discovering the analogy between these transitions, this work paves the way for a deeper understanding of quantum many-body systems. Using a method known as Lyapunov analysis, the team demonstrated the existence of spectral phase transitions in quantum systems under measurement. Furthermore, they found that the critical point of these spectral phase transitions coincides with the critical point of entanglement transitions. For more details, please refer to the related link.
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2025-01-09
Paper of the WeekWeek 2, January 2025
Title: Imaginary Hamiltonian variational ansatz for combinatorial optimization problems Author: Xiaoyang Wang, Yahui Chai, Xu Feng, Yibin Guo, Karl Jansen, Cenk Tüysüz arXiv: http://arxiv.org/abs/2408.09083v2 Title: GRB Redshift Classifier to Follow-up High-Redshift GRBs Using Supervised Machine Learning Author: Maria Giovanna Dainotti, Shubham Bhardwaj, Christopher Cook, Joshua Ange, Nishan Lamichhane, Malgorzata Bogdan, Monnie McGee, Pavel Nadolsky, Milind Sarkar, Agnieszka Pollo, Shigehiro Nagataki arXiv: http://arxiv.org/abs/2408.08763v3 Title: Isosceles trapezoids of unit area with vertices in sets of infinite planar measure Author: Junnosuke Koizumi arXiv: http://arxiv.org/abs/2501.01914v1 Title: From planar to annular to toroidal bracket polynomials for pseudo knots and links Author: Ioannis Diamantis, Sofia Lambropoulou, Sonia Mahmoudi arXiv: http://arxiv.org/abs/2501.00736v1 Title: Monte Carlo simulation of the $SU(2)/\mathbb{Z}_2$ Yang--Mills theory Author: Motokazu Abe, Okuto Morikawa, Hiroshi Suzuki arXiv: http://arxiv.org/abs/2501.00286v1 Title: Deep learning for exploring hadron-hadron interactions Author: Lingxiao Wang arXiv: http://arxiv.org/abs/2501.00374v1
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2025-01-02
Paper of the WeekWeek 1, January 2025
Title: QCD sum rule approach to Okamoto-Nolen-Schiffer anomaly Author: Hiroyuki Sagawa, Tomoya Naito, Xavier Roca-Maza, Tetsuo Hatsuda arXiv: http://arxiv.org/abs/2412.19851v1 Title: Jackiw-Teitelboim Gravity and Lorentzian Quantum Cosmology Author: Masazumi Honda, Hiroki Matsui, Kota Numajiri, Kazumasa Okabayashi arXiv: http://arxiv.org/abs/2412.20398v1 Title: Phase and equation of state of finite density QC$_2$D at lower temperature Author: Etsuko Itou, Kei Iida, Kotaro Murakami, Daiki Suenaga arXiv: http://arxiv.org/abs/2412.18825v1 Title: Violation of Parity and Flavor Symmetries in a Nambu-Jona-Lasinio Model Author: Yukimi Goto, Tohru Koma arXiv: http://arxiv.org/abs/2412.19244v1
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2025-01-02
Press Release
Ancient DNA unlocks new understanding of migrations in the first millennium AD
A new study published in Nature reveals waves of human migration across Europe during the first millennium AD using a more precise method of analysing ancestry with ancient DNA. Led by Leo Speidel, ECL Unit Leader at RIKEN iTHEMS, formally a Sir Henry Wellcome postdoctoral researcher at the Francis Crick Institute and UCL, alongside Pontus Skoglund at the Francis Crick Institute, this study reports a new data analysis method called Twigstats. Applied to over 1500 ancient genomes, the new approach reveals previously unknown details of migrations in Europe during the first millennium AD (year 1 to 1000), encompassing the Iron Age, the fall of the Roman Empire, the early medieval ‘Migration Period’ and the Viking Age. The new approach can be applied to populations across the world and may enable researcher to reveal more missing pieces of the puzzle in future. Please refer to the press release by the Francis Crick Institute for further details.
12 news in 2025