Wednesday, December 8, 16:00– 18:00 iTHEMS Math Seminar
Thursday, December 9, 10:00– 11:00 iTHEMS Biology Seminar
Friday, December 10, 12:30- Coffee Meeting

Defective interfering virus particles (DIPs) are viruses that are defective in a very specific way that allows them to out-compete standard, non-defective virus. It is difficult to count DIPs because they can look too similar to standard virus. So instead, people are counting them based on their effect on suppressing the standard virus population. In this talk, C. Beauchemin explained the basic biology of virus replication, what are DIPs, and how they compete with standard virus. She presented her group's mathematical model (ordinary differential equation) that describes co-infection competition with DIPs and standard virus. She also showed applications of the mathematical model to show how experiments to count DIPs can give incorrect results, and proposed some solutions.

Dr. Yoshino gave us a talk on his recent work on axions around rotating black holes. He showed results of his numerical simulations of so-called “superradiant instability” in which an axion field around a rotating black hole extracts the energy of the black hole. These results suggest that every astrophysical black hole is expected to wear a cloud of the axion.

Reported by Akira Mizuta (ABBL, RIKEN)

From American University, Prof. Nathan Harshman gave a seminar talk about topological exchange statistics in one spatial dimension on Nov. 17th, 2021. To introduce exchange statistics as done in the literature, he started with statistics for bosons and fermions and extended fractional and non-abelian exchange statistics. Then, the speaker raised questions about particle exchange in 1D and the collisions of the particles. Can a collision and an exchange at all be distinguished in one dimension? Is it reasonable to include points of coincidence in the configuration space? The way to resolve these problems is to introduce orbifolds. After pedagogically explaining the concepts of the orbifolds, he began to use the orbifold topological approach to study exchange statistics for any dimension. This approach offers great chances for novel abelian and nonabelian anyons in effectively 1D cold atom and condensed matter systems.

Reported by Thore Posske (University of Hamburg, Germany) and Ching-Kai Chiu

In the first part, he introduced the concept of simulation-based inference (SBI), which is inference methods driven by machine learning, and show some examples. In the later part, he showed some preliminary results of SBI on a biological neural circuit. We had a great discussion during Enrico’s talk. Thanks again for the fantastic talk, Enrico! We look forward to working with you.

Reported by Akinori Tanaka

Title: Flavor number dependence of QCD at finite density by the complex Langevin method
Author: Yusuke Namekawa, Yuhma Asano, Yuta Ito, Takashi Kaneko, Hideo Matsufuru, Jun Nishimura, Asato Tsuchiya, Shoichiro Tsutsui, Takeru Yokota
arXiv: http://arxiv.org/abs/2112.00150v1

Title: Emergence of the rho resonance from the HAL QCD potential
Author: Yutaro Akahoshi, Sinya Aoki, Takumi Doi
arXiv: http://arxiv.org/abs/2111.15138v1

Title: Color superconductivity in a small box: a complex Langevin study
Author: Shoichiro Tsutsui, Yuhma Asano, Yuta Ito, Hideo Matsufuru, Yusuke Namekawa, Jun Nishimura, Asato Tsuchiya, Takeru Yokota
arXiv: http://arxiv.org/abs/2111.15095v1

Title: Perturbative predictions for color superconductivity on the lattice
Author: Takeru Yokota, Yuhma Asano, Yuta Ito, Hideo Matsufuru, Yusuke Namekawa, Jun Nishimura, Asato Tsuchiya, Shoichiro Tsutsui
arXiv: http://arxiv.org/abs/2111.14578v1

Title: QHC21 equation of state of neutron star matter -- in light of 2021 NICER data
Author: Toru Kojo, Gordon Baym, Tetsuo Hatsuda
arXiv: http://arxiv.org/abs/2111.11919v1

Title: Flux tube profiles in two-color QCD at low temperature and high density
Author: Katsuya Ishiguro, Kei Iida, Etsuko Itou
arXiv: http://arxiv.org/abs/2111.13067v1

My name is Tomoki Nosaka. I have joined RIKEN iTHEMS as a research part-time worker in November 2021. My research field is the theoretical physics. I have been trying to reveal new aspects of M-theory, which is supposed to be the theory of everything though still being mysterious, by means of the supersymmetric gauge theories, matrix models and their integrability. Recently I am also interested in the quantum information theory and the various notions of chaos in quantum many-body systems which are found to be closely related to the black hole physics. I am looking forward to interacting with people in iTHEMS working with various research interests and finding a new direction of research out of it.