Volume 258

iTHEMS Weekly News Letter

Upcoming Events

Seminar

DMWG Seminar

Searching for dark matter subhalos in the Fermi-LAT catalog with Bayesian neural networks

July 10 (Mon) at 16:30 - 18:00, 2023

Slivia Manconi (Marie Skłodowska-Curie Fellow, Laboratoire d'Annecy-Le-Vieux de Physique Theorique (LAPTh), CNRS, France)

Machine learning techniques are powerful tools to tackle diverse tasks in current astroparticle physics research. For example, Bayesian neural networks provide robust classifiers with reliable uncertainty estimates, and are particularly well suited for classification problems that are based on comparatively small and imbalanced data sets, such as the gamma-ray sources detected by Fermi-Large Area Telescope (LAT).
About one third of the gamma-ray sources collected in the most recent catalogs remain currently unidentified. Intriguingly, some of these could be exotic objects such as dark subhalos, which are overdensities in dark matter halos predicted to form by cosmological N-body simulations. If they exist in the Milky Way, they could be detected as gamma-ray point sources due to the annihilation or decay of dark matter particles into Standard Model final states.
In this talk I will discuss our recent work* in which, after training on realistic simulations, we use Bayesian neural networks to identify candidate dark matter subhalos among unidentified gamma-ray sources in Fermi-LAT catalogs. Our novel framework allows us to derive conservative bounds on the dark matter annihilation cross section, by excluding unidentified sources classified as astrophysical-like.

Reference

  1. Anja Butter, Michael Krämer, Silvia Manconi, Kathrin Nippel, Searching for dark matter subhalos in the Fermi-LAT catalog with Bayesian neural networks, arXiv: 2304.00032

Venue: via Zoom

Event Official Language: English

Colloquium

iTHEMS Colloquium

The eyes have it: Influenza virus infection beyond the respiratory tract

July 11 (Tue) at 14:00 - 15:30, 2023

Jessica Belser (Research Microbiologist, Influenza Division, US Centers for Disease Control and Prevention (CDC), USA)

Influenza viruses are typically considered a respiratory pathogen, but are nonetheless capable of causing ocular complications in infected individuals and establishing a respiratory infection following ocular exposure. While both human and zoonotic influenza A viruses can replicate in ocular tissue and use the eye as a portal of entry, many H7 subtype viruses possess an ocular tropism in humans, though the molecular determinants that confer a non-respiratory tropism to a respiratory virus are poorly understood. In this presentation, I will discuss the establishment of several mammalian models to study ocular exposure and ocular tropism, ongoing investigations conducted in vitro and in vivo to elucidate properties associated with ocular-tropic viruses, and ways in which this information can improve efforts to identify, treat, and prevent human infection following ocular exposure to influenza viruses. Continued investigation of the capacity for respiratory viruses to gain entry to the respiratory tract and to cause ocular complications will improve understanding of how these pathogens cause human disease, regardless of the virus subtype or exposure route.

Venue: Okochi Hall, 1F Laser Science Laboratory, RIKEN / via Zoom

Event Official Language: English

Seminar

iTHEMS Seminar

Conserved charges in the quantum simulation of integrable spin chains

July 12 (Wed) at 13:30 - 15:00, 2023

Juan William Pedersen (Ph.D. Student, Graduate School of Arts and Sciences, The University of Tokyo)

In this talk, we present the result of the quantum simulation of the spin-1/2 Heisenberg XXX spin chain. We implement the integrable Trotterization algorithm, which allows us to control the Trotter error with conserved charges remaining conserved, on a real quantum computer and classical simulators. We study the effects of quantum noise on the time evolution of several conserved charges and specifically observe the decay of the expectation values. Our work improves our understanding of quantum noises and can potentially be applied to benchmark quantum devices and algorithms.

Venue: Seminar Room #359, 3F Main Research Building, RIKEN / via Zoom

Event Official Language: English

Seminar

iTHEMS Biology Seminar

Evolution of dormant egg production and their hatching rate in Aedes albopictus

July 13 (Thu) at 16:00 - 17:00, 2023

Yusuke Kuwano (Ph.D. Student, The Graduate University for Advanced Studies (SOKENDAI))

Mosquitoes are important insect vectors of infectious diseases in humans, and knowledge of their population dynamics is pivotal in disease control. Some mosquito species have dormancy in their life history to survive harsh environments. However, the population dynamics of mosquitoes have not yet been well understood due to the lack of field and experimental data on dormancy. For that reason, I modeled the population dynamics of mosquitoes that face environmental fluctuations and examine the evolution of egg dormancy strategy to survive harsh periods. I found that the ESS dormancy fraction monotonically increases with the period of environmental fluctuation. Next, I analyzed evolutionary traits of the dependence of the dormancy rate and the hatching rate from dormant egg on soil moisture content and conducted evolutionary simulations using actual weather measurement in Tokyo. The results of the hatching rate from dormant egg showed that two mosquito phenotypes having distinctly different responses to soil moisture were selected.

Venue: via Zoom

Event Official Language: English

Colloquium

The 23rd MACS Colloquium thumbnail
Maskawa Building for Education and Research venue photo

MACS ColloquiumSupported by iTHEMS

The 23rd MACS Colloquium

July 14 (Fri) at 14:45 - 18:00, 2023

Tetsushi Ito (Associate Professor, Division of Mathematics and Mathematical Sciences, Graduate School of Science, Kyoto University)
Aya Ishihara (Professor, International Center for Hadron Astrophysics / Institute for Advanced Academic Research, Chiba University)

14:45-15:00 Teatime discussion
15:00-16:00 Talk by Dr. Tetsushi Ito (Associate Professor, Division of Mathematics and Mathematical Sciences, Graduate School of Science, Kyoto University)
16:15-17:15 Talk by Prof. Aya Ishihara (Professor, International Center for Hadron Astrophysics / Institute for Advanced Academic Research, Chiba University)
17:15-18:00 Discussion

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

Event Official Language: Japanese

Lecture

3rd QGG Intensive Lectures: Spinfoam path integrals for Quantum Gravity

July 26 (Wed) - 28 (Fri), 2023

Etera Livine (Research Director CNRS, Ecole Normale Supérieure de Lyon, France)

At the crossroads of several approaches to quantum gravity, Spinfoams propose a discrete path integral for quantum general relativity built from topological field theory. With the spectrum of geometric operators directly read from the representation theory of the local symmetry group, they can be interpreted as a quantized version of Regge calculus and can be understood as implementing the dynamics of quantum states geometry in loop quantum gravity. I will explain the basics of the formalism, the motivations, the mathematical framework and the main tools. In three space-time dimensions, the spinfoam quantization of 3d gravity is given by the Turaev-Viro topological invariant, which is intimately related to the quantization of Chern-Simons theory. I will explain in particular how the spinfoam amplitudes solve the Wheeler-de Witt equation, implement the invariance under 3d diffeomorphisms (despite being formulated in a discretized space-time) and lead to a quasi-local version of holography. In four space-time dimensions, general relativity can be formulated as an almost-topological theory and I will explain how the existing spinfoam models introduce a sea of topological defects to re-create the gravitational degrees of freedom from a topological path integral. Finally, I will show how spinfoams are naturally defined in terms of group field theory, which are generalized tensor models, and the prospects that this opens. I will conclude with the main challenges and open lines of research of the field.

Program:

July 26
10:00 - 10:15 Registration and reception
10:15 - 11:45 Lecture 1
11:45 - 13:30 Lunch & coffee break
13:30 - 15:00 Lecture 2
15:00 - 16:00 Coffee break
16:00 - 17:00 Lecture 3
17:10 - 18:30 Short talk session

July 27
10:00 - 11:45 Lecture 4
11:45 - 13:30 Lunch & coffee break
13:30 - 15:00 Lecture 5
15:00 - 16:00 Coffee break
16:00 - 17:00 Lecture 6
17:30 - 20:00 Banquet

July 28
10:00 - 11:45 Lecture 7
11:45 - 13:30 Lunch & coffee break
13:30 - 15:00 Lecture 8
15:00 - 16:00 Coffee break
16:00 - 17:30 Lecture 9 & Closing

Venue: #435-437, 4F, Main Research Building, RIKEN

Event Official Language: English

Lecture

Higher Algebra in Geometry

July 31 (Mon) - August 10 (Thu), 2023

Hiro Lee Tanaka (Assistant Professor, Department of Mathematics, Texas State University, USA)

In these lectures, we will shed light on modern tools of higher algebra, where the traditional structures of algebra yield themselves only after controlled deformations. We will introduce infinity-categories, spectra, operads, and other standard tools of the last decade. The main applications will be to encode various higher-algebraic structures that inevitably arise in, and shed light on, geometry and topology. If time permits, we will illustrate how spectra naturally arise in geometric invariants.

The audience is imagined to consist of mathematicians interested in applications of infinity-categorical tools -- so a broad range of geometers (including topologists) and algebraists. From Lecture Two onward, I will assume basic knowledge of algebraic topology (e.g., the material of Hatcher) and homological algebra.

These lectures will be held between July 31 and August 10, each from 10:30 to 12:00, for a total of 8 lectures.

1st Week: Jul 31(mon), Aug 1(tue) - 3(thu)
- Introduction to ideas of higher algebra in geometry, for a general audience.
- Introduction to infinity-categories and to spectra.

2nd Week: Aug 7(mon) - 10(thu)
- Examples in geometry and topology, including invariants of Legendrian links and generating functions.
- Future Directions.

Profile:
Hiro Lee Tanaka is an assistant professor in the Department of Mathematics. After receiving his Ph.D. from Northwestern University and completing postdoctoral work at Harvard University, he conducted research at the Mathematical Sciences Research Institute in Berkeley, California, and at the Isaac Newton Institute in Cambridge, England. His research aims to fuse the higher structures in modern algebra with geometries emerging from both classical mechanics and supersymmetric field theories. Beyond research, Tanaka engages in efforts to create more equitable and supportive environments throughout the mathematics community.

References

  1. Jacob Lurie, Higher Topos Theory (PDF 4.8MB), doi: 10.1515/9781400830558
  2. Jacob Lurie, Higher Algebra (PDF 6.9MB)
  3. Kerodon - an online resource for homotopy-coherent mathematics
  4. Jacob Lurie, Hiro Lee Tanaka, Associative algebras and broken lines, arXiv: 1805.09587
  5. Jacob Lurie, On the Classification of Topological Field Theories, arXiv: 0905.0465
  6. Oleg Lazarev, Zachary Sylvan, Hiro Lee Tanaka, The infinity-category of stabilized Liouville sectors, arXiv: 2110.11754
  7. Araminta Amabel, Artem Kalmykov, Lukas Müller, Hiro Lee Tanaka, Lectures on Factorization Homology, Infinity-Categories, and Topological Field Theories, arXiv: 1907.00066
  8. David Ayala, John Francis, Hiro Lee Tanaka, Factorization homology of stratified spaces, arXiv: 1409.0848
  9. David Nadler, Hiro Lee Tanaka, A stable infinity-category of Lagrangian cobordisms, arXiv: 1109.4835
  10. David Gepner, An Introduction to Higher Categorical Algebra, arXiv: 1907.02904

Venue: #435-437, Main Research Building, RIKEN / via Zoom

Event Official Language: English

Upcoming Visitor

July 11 (Tue), 2023

Johannes Henn

Director and Department Head, Max Planck Institute for Physics, Germany

Visiting Place: RIKEN Wako Campus

Person of the Week

Jan Schuette-Engel thumbnail

Self-introduction: Jan Schuette-Engel

2023-07-03

Hello, I’m Jan and I work on theoretical high energy particle physics, astroparticle physics and cosmology. I’m based at UC Berkeley.
My work focuses on probing high energy particle physics with gravitational waves (GWs). Additionally, I develop novel ideas for earth based experiments to discover new physics.

Paper of the Week

Week 2, July 2023

2023-07-06

Title: String-net formulation of Hamiltonian lattice Yang-Mills theories and quantum many-body scars in a nonabelian gauge theory
Author: Tomoya Hayata, Yoshimasa Hidaka
arXiv: http://arxiv.org/abs/2305.05950v1

Title: HBT signature for clustered substructures probing primordial inhomogeneity in hot and dense QCD matter
Author: Kenji Fukushima, Yoshimasa Hidaka, Katsuya Inoue, Kenta Shigaki, Yorito Yamaguchi
arXiv: http://arxiv.org/abs/2306.17619v1

If you would like to cancel your subscription or change your email address,
please let us know via our contact form.