Matching markets often suffer from fragmentation, which leads to inefficiency. We model a fragmented market in a school-choice context and offer a practically relevant method for integration. Specifically, each student and school belong to a region, and we allow for inter-regional transfer of students with "balancedness" constraint: a matching is said to be balanced if, for each region, the outflow of students from that region to other regions is equal to the inflow of students from the latter to the former. Using a directed bipartite graph defined on students and schools, we characterize the set of Pareto efficient matchings among those that are individually rational, balanced and fair (efficient iBF). We also provide a class of polynomial-time algorithms to compute such matchings. When each region favors local students in their priority, the outcome of an algorithm from this class weakly improves student welfare upon the outcome where each region independently uses the deferred acceptance mechanism. Various real-life examples of fragmentation are discussed, and we illustrate how our method would address the issue.

In the 11th event of the Intensive Lecture Series, organized by the Quantum Gravity Gatherings (QGG) study group at RIKEN iTHEMS, we will have Prof. Yasuyuki Hatsuda from Rikkyo University, who will deliver a three-day lecture series on the analytic methods in black hole perturbation theory.

Black hole perturbation theory plays a very important role in the developments of modern physics. For instance, in gravitational wave astronomy, it can describe the ringdown phase during the merger events of binary black holes. As the frequency and decay rate of each quasinormal mode are unique to the remnant black hole, one can test extreme-gravity physics by extracting those modes from the ringdown signal. In addition, the computation of black hole quasinormal modes based on black hole perturbation theory has relations connecting to conformal field theories and even to the computations of tidal Love numbers. With the broad applications, we expect this lecture series to provide fresh perspectives to researchers across a wide range of fields and to inspire new directions in their own research.

The lectures will be delivered in a blackboard-style format (in English), designed to foster interaction, active participation, and in-depth Q&A discussions. In addition, short talk sessions will be held, giving participants the opportunity to present briefly on topics of their choice. Through this informal and dynamic setting, we hope to spark active interactions among participants and create an environment where ideas can be shared openly and enthusiastically.

This event will take place in person only.

Target audience:
Senior scholars, early-career researchers, and students are all warmly welcome.

Registration deadline:
July 31, 2026

We are pleased to announce that the SNP School 2026 will be held at Aobayama Campus, Tohoku University, from 7th to 11th, September, 2026. This is the 15th of the series which has been held every year since 2012.

The school provides lectures that cover subjects from basics to the frontiers of strangeness nuclear physics as well as other related fields such as astrophysics, atomic physics, etc. Lecturers are invited both from theoretical or experimental physics, and their materials are prepared to be useful to students and also to researchers who would have wider interests.

For more details, please see the related link.

Many devastating crop diseases, including anthracnose and rice blast, begin when a fungal pathogen builds a single infection cell called an appressorium. This single cell generates up to ~8 megapascals of turgor pressure (roughly 40 times a car tire’s air pressure), among the highest documented in any living organism, to physically rupture the plant's tough surface. This pressure arises because the cell wall acts as a semipermeable membrane, retaining internal osmolytes such as glycerol while allowing water to pass. What confers this selective permeability had remained unknown for decades: melanin was long assumed responsible, but turgor still forms in melanin-deficient mutants.

Using genome editing and direct biochemical analysis of these fungi, we identified two enzymes, PKS2 and PBG13, that synthesize a novel polymer from dihydroxyhexanoic acid (DHHA), which narrows cell-wall pore size at the nanometer scale and is required for turgor generation (Kumakura* et al., Science, 2026). I will frame this system as a living adaptive porous material and discuss questions open to mathematical and physical modeling, including how pore geometry sets the limits of selective permeability.

The redshifted 21 cm line signal is a unique probe for the Epoch of Reionisation by tracking the evolution of the averaged intergalactic medium properties as well as their fluctuations, enabling tomographic studies. Accurate modelling of the 21 cm global and power spectrum signals is crucial for interpreting measurements from current and forthcoming 21 cm experiments. Theoretical predictions usually post-process reionisation simulations with optical depth approximation, which treats local line broadening and peculiar velocities approximately and often leads to divergences due to its velocity gradient term. I will present our cosmological 21 cm line radiative transfer (C21LRT) formulation which resolve these issues naturally. I will compare the 21-cm signals calculated with C21LRT and the conventional optical depth method, and highlight the need to fully quantify the uncertainties of using the optical depth method for exploring the 21-cm signals associated from various possible reionisation scenarios.

In 1980s, K. Saito introduced the primitive forms in his study of periods as to generalize the elliptic period integral theory to higher dimensions. An important consequence was that there exists a flat structure on the space of universal unfolding of a singularity. Later after Witten proposed his famous conjecture relating the intersection theory on moduli space to the integrable hierarchy, this flat structure was re-discovered by Dubrovin, and nowadays it is referred as a Frobenius mafniold structure. Frobenius mafniolds provide a convenient tool for formulating the mirror symmetry, which was a special type of duality among string theories orginally studied by physicits. In this talk, I will explain the related constructions, and show by examples how the study of primitive forms gives prediction of geometric quantities such as Gromov-Witten invariants.

Tannaka duality asks to what extent a geometric object can be recovered from a category naturally associated with it. In this talk, the geometric objects are topological spaces, and the associated categories are their categories of sheaves of spectra.
I showed that, for compact Hausdorff spaces X and Y, every colimit-preserving symmetric monoidal functor from Shv(X; Sp) to Shv(Y; Sp) arises uniquely from a continuous map from Y to X, where Shv(X; Sp) denotes the (∞, 1)-category of sheaves of spectra on X. The main ingredient is an adjunction between the construction of sheaves and a new variant of the smashing spectrum. I will also discuss variants of this machinery to broader classes of spaces, including ongoing work on toposes.

This workshop brings together mathematicians and physicists to explore the deep connections among quantum information, mathematics, and physics. Topics span quantum gravity, condensed matter physics, quantum computing, and quantum error correction, with an emphasis on the mathematical structures that underlie entanglement and quantum information across these fields.

The program is designed to foster genuine cross-disciplinary dialogue, allowing ample time for discussion alongside formal talks.

[Invited speakers]
Akira Furusaki (RIKEN CEMS/iTHEMS)
Marcel Franz (UBC / SBQMI)
Ching-Kai Chiu (iTHEMS)
Jasmin Bedow (UBC)
Max McGinley (UBC)
Yosuke Kubota (Kyoto University)
Shunji Matsuura (RIKEN iTHEMS)
Bartosz Regula (RIKEN RQC)
Ryuji Takagi (University of Tokyo)
Sisi Zhou (Perimeter Institute)
Olivia Di Matteo (UBC / SBQMI)
Daochen Wang (UBC Computer Science)
Polina Feldmann (UBC)
Masazumi Honda (RIKEN iTHEMS)
Yasuyuki Kawahigashi (RIKEN iTHEMS)
Carolyn Zhang (UBC)
Masahito Yamazaki (Kavli IPMU, University of Tokyo)
Aswin Parayil Mana (University of Tokyo)
Alex May (Perimeter Institute)
Masamichi Miyaji (RIKEN iTHEMS)
Mark Van Raamsdonk (UBC Physics & Astronomy)

Note. The lectures will be given in Japanese. This workshop will be jointly organized by RIKEN AIP.

During this five-day workshop, we will hold a learning seminar and intensive lectures on gestalt theory, which was recently developed by Scholze and Stefanich.

Gestalt theory is a new geometric framework that unifies various derived analytic geometry and higher sheaf theory, building on the foundations of higher and derived category theory.
At this event, we will host Ko Aoki, who has contributed to the foundations and development of the theory, for the intensive lecture session.

During the first three days of the workshop, we will feature tutorial lecture sessions, presented by the participants. All lectures will be given in Japanese, with the aim of promoting the dissemination and development of gestalt theory in Japan.

Lecture
Professor Mingsheng Ying is internationally recognised for his contributions to quantum computing, quantum programming, and quantum software verification. He is a Distinguished Professor at the UTS Centre for Quantum Software and Information at the University of Technology Sydney.

His research interests include quantum computation, programming language theory, quantum program semantics, verification, and the foundations of quantum software.

Professor Ying is Co-Editor-in-Chief of ACM Transactions on Quantum Computing and has served in editorial roles for several leading journals and conferences.

Abstract
Recent advances in quantum hardware have brought the field from prototype devices to increasingly practical platforms.

To fully realise the potential of quantum computing, quantum programming and software-development technologies will play a crucial role.

This lecture series systematically introduces the theoretical foundations of quantum programming, including operational and denotational semantics, quantum program logics with an emphasis on quantum Hoare logic, verification and analysis of quantum programs, and quantum recursive programming.

The lectures will also discuss open problems that may inspire future research in quantum programming.

Join us for a comprehensive workshop on the application of quantum computing to nuclear physics, bringing together experts from around the world to share the latest developments and advancements in this rapidly evolving field. The workshop will cover a broad range of topics, including quantum algorithms, quantum computing hardware, and their applications to lattice field theories, gauge field theories, scattering, nuclear structure, and nuclear astrophysics.

The workshop will provide ample opportunities for participants to exchange ideas, share their research, and initiate new collaborations. Through a combination of presentations and interactive discussion sessions, we aim to foster a collaborative environment that drives innovation and advances our understanding of the intersection of quantum computing and nuclear physics.

[Workshop Schedule]
The workshop will start from the morning of October 13
The banquet will be held on the evening of October 15
[Important Dates]
Registration deadline with oral presentation: August 31, 2026
Recommended to register by: August 31, 2026

[Invited Speakers]
A. Baha Balantekin (University of Wisconsin Madison)
Raul Briceño (University of California Berkeley/Lawrence Berkeley National Laboratory)
Philipp Höhn (Okinawa Institute of Science and Technology
Etsuko Itou (Kyoto University)
Dima Kharzeev (Brookhaven National Laboratory/Stony Brook University)
Yuta Kikuchi (Quantinuum)
Denis Lacroix (IJCLab)
Dean Lee (Michigan State University)
Mario Motta (IBM Quantum)
Takeshi Sato (University of Tokyo)
Ionel Stetcu (Los Alamos National Laboratory)
Paul Stevenson (University of Surrey)
Nathan Wiebe (University of Toronto)
Seiji Yunoki (RIKEN)

[Organizers]
Ermal Rrapaj (Lawrence Berkeley National Laboratory/RIKEN, Chair)
Carlo Barbieri (University of Milan)
Tetsuo Hatsuda (RIKEN)
Masaaki Kimura (RIKEN/University of Tokyo)
Haozhao Liang (University of Tokyo)
Tomoya Naito (University of Tokyo/RIKEN)
Enrico Prati (University of Milan)
Alessandro Roggero (University of Trento)
Takeshi Sato (University of Tokyo)

Motivated by applications to topological data analysis, in the last years we have been witnessing a growing interest in new (topological, homological, categorical) features associated to graphs. The aim of the talk is to describe a recently developed (co)homology theory of directed graphs, called multipath cohomology, whose definition is inspired by Khovanov homology of knots. We will show its relations with more established invariants, such as chromatic homology of graphs, Hochschild homology of algebras, and matching complexes. If time allows it, we will show that the ranks of multipath cohomology, when restricted to graphs with bounded genus, grow at most polynomially in the number of edges, and that the order of its torsion is bounded. This will depend upon structural properties of (the representation category of) graphs, such as its Noetherianity properties.

Workshop Overview
Majorana modes lie at the heart of contemporary condensed-matter physics, exhibiting non-Abelian exchange statistics; when protected by topology, they are robust against environmental perturbations. Here, “Majorana mode” is used broadly to include a localized zero-energy Majorana state (a Majorana zero mode) and chiral Majorana edge states with gapless dispersion crossing zero energy.

This three-day in-person workshop returns to fundamentals and open questions. It opens with a tutorial session on the afternoon of October 13 for non-experts and adjacent fields, and emphasizes rigorous theory–experiment dialogue, robust methodology, and concrete benchmarks for realizing and testing Majorana modes.

Participants
Experimentalists and theorists working on Majorana modes
Researchers in adjacent fields (quantum materials, superconductivity, mesoscopic physics)
Graduate students and postdocs interested in entering the field
Topics include (non-exhaustive)
Majorana zero modes in a variety of nanostructures
Chiral Majorana edge states in quantum spin liquids and other platforms
Disorder, interactions, and realistic device modeling
Experimental diagnostics and “smoking gun” signatures
Topological Quantum Spin Systems

Artificial intelligence is having a transformative impact on health and scientific discovery. This presentation will trace the evolution from foundational breakthroughs to the sophisticated capabilities of today's large-scale AI models. It will explore how these advanced systems are creating new possibilities across the healthcare landscape, from accelerating therapeutic development to enhancing diagnostic processes and interpreting complex medical data. The session will also take a deeper look at the future possibilities for AI in health and explore the emerging role of agentic AI in scientific discovery. The core theme is the responsible development of AI to create tools that assist scientists, support healthcare professionals, and empower users.

Bio:
Dr Joseph Ledsam leads Google Health in Japan, where he works across AI research, digital health and health in Google products. He has led research in medical AI, genomics and drug discovery published in journals including Nature, Nature Medicine and Nature Methods. Before moving to Japan he worked as a medical doctor in the UK, and founded the Health Research and Genomics teams in Google DeepMind. He obtained his medical degree from The University of Leeds, UK, and was a research fellow at University College London during his clinical residency.

The KEK Theory Workshop is an annual workshop on string theory and quantum field theory.
Since 2014, it has been held every winter as an international workshop and has become one of the major annual events in the high-energy physics community in Japan.
This year’s workshop will be held on site at the KEK Tsukuba Campus from November 25 to 27, and it will be jointly organized with RIKEN iTHEMS.

The workshop this year aims to provide a forum for extensive discussions on recent developments in string theory, matrix models, gauge/gravity duality, black-hole microstates, lattice constructions of chiral gauge theories, and open quantum systems.