Volume 211
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Volume 211
August 12, 2022
Hot Topic
iTHEMS Science Outreach Workshop 2022 was held on July 29-31, 2022
2022-08-08
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.
iTHEMS Science Outreach Workshop 2022
July 29 (Fri) - 31 (Sun), 2022
Seminar Report
iTHEMS Math Seminar by Prof. Narutaka Ozawa on August 2, 2022
2022-08-08
On August 2, Professor Narutaka Ozawa (RIMS, Kyoto University) gave a talk entitled "Product Replacement Algorithm, Semidefinite Programming, and Operator Algebras" in the iTHEMS Math Seminar. He elegantly explained how his recent study on Kazhdan's property (T) ties the field of functional analysis/operator algebras and that of computer sciences.
Reported by Michiya Mori
Product Replacement Algorithm, Semidefinite Programming, and Operator Algebras
August 2 (Tue) at 16:00 - 17:00, 2022
Seminar Report
iTHEMS Math Seminar by Dr. Hokuto Konno on July 15, 2022
2022-08-05
On July 15, there was a math seminar by Professor Konno. He gave an introductory talk on the Seiberg-Witten Floer homotopy type.
Reported by Keita Mikami
Seiberg-Witten Floer homotopy
July 15 (Fri) at 14:00 - 16:30, 2022
Upcoming Events
Seminar
Testing Astrophysical Models from the Shadow of the Galactic Center Black Hole
August 26 (Fri) at 14:00 - 15:00, 2022
Yosuke Mizuno (T.D. Lee Fellow / Associate Professor, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, China)
We present the first Event Horizon Telescope (EHT) observations of Sagittarius A* (Sgr A*), the Galactic center source associated with a supermassive black hole. These observations were conducted in 2017 using a global interferometric array of eight telescopes operating at a wavelength 1.3 mm. A variety of imaging and modeling analyses all support an image that is dominated by a bright, thick ring with a diameter of ~50 micro-arcsecond. Using a large suite of numerical simulations, we demonstrate that the EHT images of Sgr A* are consistent with the expected appearance of a Kerr black hole with mass ∼4 million solar mass, which is inferred to exist at this location based on previous infrared observations of individual stellar orbits, as well as maser proper-motion studies. Our model comparisons disfavor scenarios where the black hole is viewed at high inclination (i > 50 deg), as well as non-spinning black holes and those with retrograde accretion disks. Our results provide direct evidence for the presence of a supermassive black hole at the center of the Milky Way. In this talk, I will focus on more theoretical interpretation and model comparison to understand the accretion flow properties nearby Sgr A*.
Venue: via Zoom
Event Official Language: English
Seminar
Study of the eta' meson in nuclei in the LEPS2/BGOegg experiment
August 26 (Fri) at 16:30 - 18:00, 2022
Natsuki Tomida (Specially Appointed Assistant Professor, Center for Science Adventure and Collaborative Research Advancement (SACRA), Graduate School of Science, Kyoto University)
A large mass reduction of eta'(958) meson in nuclear medium owing to its UA(1) anomaly is expected in several model calculations. We carried out the LEPS2/BGOegg experiment at SPring-8 to study eta' meson properties in nuclei. If there is a large mass reduction in nuclei, an eta' meson and a nucleus may form a bound state. We searched for the eta'-nucleus bound states via missing mass spectroscopy of the 12C(gamma, p) reaction. To suppress background events from multi-meson production, we simultaneously measured decay products from the eta'-nucleus system for the first time.
We also carried out the missing mass spectroscopy simultaneously detecting an eta' meson escaping from a nucleus for the first time. We will show the experimental results and comparisons with theoretical calculations. We will also show the preliminary results of the line shape analysis of the invariant mass spectra of the eta'->2gamma decay in the gamma+12C->eta'+X reaction.
Reference
- N. Tomida et al. (LEPS2/BGOegg Collaboration), Search for η ′ Bound Nuclei in the 12 C ( γ , p ) Reaction with Simultaneous Detection of Decay Products, Phys. Rev. Lett. 124, 202501 (2020), doi: 10.1103/PhysRevLett.124.202501
Venue: Common Room #246-248, 2F Main Research Building, RIKEN / via Zoom
Event Official Language: English
Workshop
DM3 - Deep insights and Multiple strategies for Deciphering the Mystery of Dark Matter
September 15 (Thu) - 17 (Sat), 2022
Venue: SUURI-COOL (Kobe), #S704-S705, Integrated Innovation Building (IIB), Kobe Campus, RIKEN / via Zoom
Event Official Language: English
Paper of the Week
Week 2, August 2022
2022-08-11
Title: Calibration of nuclear charge density distribution by back-propagation neural networks
Author: Zu-Xing Yang, Xiao-Hua Fan, Tomoya Naito, Zhong-Ming Niu, Zhi-Pan Li, Haozhao Liang
arXiv: http://arxiv.org/abs/2205.15649v2
Title: Stability against three-body clustering in one-dimensional spinless p-wave fermions
Author: Yixin Guo, Hiroyuki Tajima
arXiv: http://arxiv.org/abs/2208.03654v1
Title: Thermal Ringdown of a Kerr Black Hole: Overtone Excitation, Fermi-Dirac Statistics and Holography
Author: Naritaka Oshita
arXiv: http://arxiv.org/abs/2208.02923v1
Title: Tricritical phenomena in holographic chiral phase transitions
Author: Masataka Matsumoto
arXiv: http://arxiv.org/abs/2208.02605v1
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