Colloquium

Mirror symmetry and KAM theory

April 16 (Fri) at 13:30 - 15:00, 2021

Kenji Fukaya (Permanent Member, Simons Center for Geometry and Physics, Stony Brook University, New York, USA)

13:30pm-15:00pm (JST) Mirror symmetry is a phenomenon discovered in String theory and is much discussed recently in mathematics especially in the field of complex (algebraic) geometry and symplectic geometry. Strominger-Yau-Zaslow found that this phenomenon is closed related to a Lagrangian torus fibration. In an integrable system in Hamiltonian dynamics, the phase space is foliated by Lagrangian tori. I would like to explain a program that the Lagrangian torus fibration found by Strominger-Yau-Zaslow could be regarded as one appearing certain integrable system and KAM theory (which describes a amiltonian dynamics that is a perturbation of an integrable system) could appear in the situation of Mirror symmetry.

Venue: via Zoom

Event Official Language: English

The 14th MACS Colloquium

February 17 (Wed) at 15:00 - 17:30, 2021

Yoshihiro Kaneko (Associate Professor, Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University)

15:00- Talk by Prof. Yoshihiro Kaneko 16:05- MACS Report Meeting FY2019 16:30- Discussion of each study group

Venue: via Zoom

Event Official Language: Japanese

Geometry (形); Inconspicuous regulator that determines the fate of cells

December 14 (Mon) at 10:00 - 11:30, 2020

Sungrim Seirin-Lee (Professor, Hiroshima University)

December 14 at 10:00-11:30, 2020 (JST) December 13 at 20:00-21:30, 2020 (EST) In the history of mathematical study in pattern formation, the effect of domain has been considered as an important factor that can regulate spatial patterning. However, it is still unknown in biology how the geometry of the domain such as nuclear or cellular shapes can directly regulate the cell fate. In this talk, I will introduce two studies of spatial reorganization in chromatin and cellular dynamics and show that the domain is likely to play a critical role in determining the cell function.

Venue: via Zoom

Event Official Language: English

The Unreasonable Effectiveness of Quantum Theory in Mathematics

November 26 (Thu) at 10:00 - 11:30, 2020

Robbert Dijkgraaf (Director, Institute for Advanced Study in Princeton, USA)

November 26 at 10:00-11:30, 2020 (JST) November 25 at 20:00-21:30, 2020 (EST) The physical concepts of quantum theory, in particular of quantum gravity and string theory, have proven to be extremely powerful in addressing deep problems in pure mathematics, from knot invariants to algebraic geometry. Is there such a thing as “quantum mathematics”? Should we add Feynman diagrams, strings, branes and black holes to the language of mathematics?

Venue: via Zoom

Event Official Language: English

The 13rd MACS Colloquium

November 13 (Fri) at 15:00 - 18:00, 2020

Shin-ya Kawaguchi (Professor, Division of Biological Sciences, Graduate School of Science, Kyoto University)
Yuji Sugita (Senior Research Scientist, iTHEMS / Chief Scientist, Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research (CPR))

15:00- Talk by Prof. Shin-ya Kawaguchi 16:15- Talk by Dr. Yuji Sugita 17:15- Discussion

Venue: via Zoom

Event Official Language: Japanese

The 12nd MACS Colloquium

July 17 (Fri) at 15:00 - 18:30, 2020

Yasuaki Hiraoka (Professor, Kyoto University Institute for Advanced Study (KUIAS) / Team Leader, Topological Data Analysis Team, RIKEN Center for Advanced Intelligence Project (AIP))
Motomu Tanaka (Professor, Physical Chemistry of Biosystems, Heidelberg University, Germany / Professor, Center for Integrative Medicine and Physics, Kyoto University Institute for Advanced Study (KUIAS))

15:00- Talk by Prof. Yasuaki Hiraoka 16:15- MACS Student Conference FY2020 17:30- Talk by Prof. Motomu Tanaka

Venue: via Zoom

Event Official Language: Japanese

iTHEMS Intensive Course [4] : "Adaptive strategies of organisms, their mathematical bases" - Cancer as a mini-evolutionary process

June 25 (Thu) at 15:00 - 16:30, 2020

Yoh Iwasa (Senior Advisor, iTHEMS / Professor, Kwansei Gakuin University / Professor Emeritus, Kyushu University)

Living systems exhibit features distinct from nonliving physical systems: their structure and behaviors appear to be chosen adaptive. They are the outcomes of evolution. Mathematical formalisms developed in engineering and social sciences (e.g. control theory, game theory, evolutionary game theory) are sometimes very useful in biology.

Venue: via Zoom

Event Official Language: English

Emergence of life in an inflationary universe

May 11 (Mon) at 15:30 - 17:00, 2020

Tomonori Totani (Professor, Department of Astronomy, Graduate School of Science, The University of Tokyo)

The origin of life may be the greatest mystery in natural science. Especially, we know almost nothing about how the first biological molecule (possibly an RNA) appeared from abiotic chemical processes. A widespread notion is that the abiogenesis probability is extremely low when we consider only random chemical reactions to polymerize a large biological molecule. However, we do not know any more efficient polymerization process expected to work in a realistic prebiotic environment. Here, I consider this problem from a viewpoint of cosmology. Cosmologists agree that the universe created by an inflation should extend far beyond the observable universe (13.8 billion light year radius). Then the inflationary universe may be sufficiently large to produce many abiogenesis events, even if we consider only the basic random polymerization. I will give a quantitative answer to this question, and discuss various implications about the origin-of-life studies.

Venue: via Zoom

Event Official Language: English

Interaction Models in Quantum Optics, Representation Theory and Number Theory

April 10 (Fri) at 15:30 - 17:00, 2020

Masato Wakayama (Senior Advisor, iTHEMS / Vice President, Tokyo University of Science)

Recently, interaction models originated in quantum optics, with the quantum Rabi model (QRM) as a distinguished representative, are appearing ubiquitously in various quantum systems including cavity and circuit quantum electrodynamics, quantum dots and artificial atoms, with potential applications to quantum information technologies such as quantum computing. Together with the integrability of QRM, demonstrated by Daniel Braak in 2011, this has led to wide discussion and development of various aspect of the QRM and its generalizations from the point of view of theoretical physics and mathematics. In this talk, firstly, we characterize the structure of the spectra of QRM and its asymmetric version via sℓ2-representations. Secondly, we introduce the non-commutative harmonic oscillator, which may be considered to be a “cover” of the QRM in the Heun ODE picture, and describe certain number theoretical aspects arising from its spectral zeta function. Further, we discuss the heat kernel and partition function of the QRM toward the number theoretical investigation of the model. In addition, a number of related open problems will be presented.

Venue: via Zoom

Event Official Language: English

The 11st MACS Colloquium

February 19 (Wed) at 15:00 - 17:30, 2020

Hiroyuki Hata (Professor, Graduate School of Science, Kyoto University)

15:00- Teatime 15:15- Talk by Prof. Hiroyuki Hata 16:40- MACS Report Meeting FY2019 The 11th MACS colloquium is supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good confectionery at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Event Official Language: Japanese

Exploring the learning principle in the brain

January 16 (Thu) at 15:30 - 17:00, 2020

Taro Toyoizumi (Team Leader, RIKEN Center for Brain Science (CBS))

Animals adapt to the environment for survival. Synaptic plasticity is considered a major mechanism underlying this process. However, the best-known form of synaptic plasticity, i.e., Hebbian plasticity that depends on pre- and post-synaptic activity, can surge coincident activity in model neurons beyond a physiological range. Our lab has explored how neural circuits learn about the environment by synaptic plasticity. The instability of Hebbian plasticity could be mitigated by a global factor that modulates its outcome. For example, TNF-alpha that mediates homeostatic synaptic scaling is released by glia, reflecting the activity level of surrounding neurons. I show that a specific interaction of Hebbian plasticity with this global factor accounts for the time course of adaptation to the altered environment (Toyoizumi et al. 2015). At a more theoretical level, I ask what is the optimal synaptic plasticity rule for achieving an efficient representation of the environment. A solution is the error-gated Hebbian rule, whose update is proportional to the product of Hebbian change and a specific global factor. I show that this rule, suitable also in neuromorphic devices, robustly extracts hidden independent sources in the environment (Isomura and Toyoizumi 2016, 2018, 2019). Finally, I introduce that synapses change by intrinsic spine dynamics, even in the absence of synaptic plasticity. I show that physiological spine-volume distribution and stable cell assemblies are both achieved when intrinsic spine dynamics are augmented in a model (Humble et al.2019).

Venue: Large Meeting Room, 2F Welfare and Conference Building (Cafeteria)

Broadcast:R311, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: English

The 10th MACS Colloquium

November 15 (Fri) at 14:45 - 18:45, 2019

Nami Sakai (Chief Scientist, Star and Planet Formation Laboratory, RIKEN Cluster for Pioneering Research (CPR))
Kazuya Watanabe (Professor, Graduate School of Science, Kyoto University)

14:45- Teatime 15:00- Talk by Dr. Nami Sakai 16:15- Talk by Prof. Kazuya Watanabe 17:45- Discussion The 10th MACS colloquium supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good confectionery at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Event Official Language: Japanese

Topological phases of matter and operator algebras

October 4 (Fri) at 15:30 - 17:00, 2019

Yasuyuki Kawahigashi (Senior Visiting Scientist, iTHEMS / Professor, Graduate School of Mathematical Sciences, The University of Tokyo)

Topological phases of matter are hot topics in recent physics and related to a wide range of mathematical fields. I will talk about their aspects related to operator algebras. Our emphasis will be on theory of tensor categories which describe interactions of anyons. This theory plays an important role in topological quantum computations. In theory of operator algebras, Jones initiated theory of subfactors and discovered the Jones polynomial, a new topological invariant for knots as an application. We apply this theory to mathematical studies of anyons.

Venue: Okochi Hall

Broadcast:R511, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: English

The 9th MACS Colloquium

July 12 (Fri) at 16:15 - 18:50, 2019

Makoto Fujita (Professor, Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo)
Kazutoshi Mori (Professor, Department of Biophysics, Division of Biological Sciences, Graduate School of Science, Kyoto University)

16:15- Teatime 16:30- Talk by Prof. Makoto Fujita 17:50- Talk by Prof. Kazutoshi Mori The 9th MACS colloquium supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good confectionery at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Event Official Language: Japanese

Spacetime Geometry of Black Holes, Wormholes, and Time Machines

July 2 (Tue) at 15:30 - 17:00, 2019

Pei-Ming Ho (Distinguished Professor, Department of Physics, National Taiwan University, Taiwan)

Since the advent of General Relativity, people have found many solutions with interesting spacetime geometries. Most notably, the black holes have attracted a lot of attention for their roles in generating gravitational waves, and for inducing the information loss paradox. In this talk, we consider black holes amongst other geometric structures and investigate the subtlety involved in the quantum effect such as Hawking radiation. In this context, we mention wormholes and time machines, and explain how they are conceptually related to the geometry under the horizon of a black hole. There will also be comments on my recent research result about how quantum effect must be large for observers sitting on top of the black hole horizon.

Venue: Large Meeting Room, 2F Welfare and Conference Building (Cafeteria)

Broadcast:R511, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: English

Quantum computing: current status and prospects

April 25 (Thu) at 15:00 - 16:30, 2019

Keisuke Fujii (Professor, Graduate School of Engineering Science, Osaka University)

Supported by extensive experimental efforts for realization of quantum computing devices, quantum computers of a hundred qubits are now within reach in the near future. This level of a quantum computer is not enough for fully fledged fault-tolerant quantum computing, but is still expected to have computational advantage against classical computers. Such a noisy intermediate scale quantum computing (NISQ) device is thought to be a testbed for proof-of-principle experiments of quantum algorithms and verification of quantum physics in the limit of extremely high complexity. In this talk, I will provide a general introduction to quantum computing starting from how and for what quantum computers work. Then I will provide an overview of the current status and prospects of the field of quantum computing. As the final part, I will also talk about our own activities on quantum-classical hybrid algorithm, which is a kind of quantum algorithms specifically designed for the NISQ devices.

Venue: Suzuki Umetaro Hall

Broadcast:R511, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: English

The 8th MACS Colloquium

April 12 (Fri) at 15:00 - 17:30, 2019

Hayato Chiba (Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

15:00- Teatime 15:15- Talk by Prof. Hayato Chiba 16:45- MACS Student Conference FY2019 The 8th MACS colloquium is supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good confectionary at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Broadcast:#235, 2F, Main Research Building

Event Official Language: Japanese

ZetaValue2019-iTHEMS Special Mathematics Colloquium

March 21 (Thu) at 14:00 - 17:30, 2019

Kohji Matsumoto (Professor, Nagoya University)
Jörn Steuding (University of Würzburg, Germany)

Prof. Kohji Matsumoto (Nagoya University) "An overview of the theory of multiple zeta-functions" Multiple zeta-functions are generalizations of the Riemann zeta-function, and its theory has been rapidly developed in these decades. It is connected with various fields of mathematics and mathematical physics. In this talk I will give an overview of some part of recent developments, mainly from the analytic viewpoint. Prof. Jörn Steuding (University of Würzburg, Germany) "On the Infinite in Number Theory" Beginning with two simple examples from elementary number theory (one of diophantine origin and one of arithmetical nature), we discuss the role of “infinity” in number theory. We touch upon topics like how to find good rational approximations to irrational quantities and the distribution of prime numbers. We conclude with a motivation of the big open question in this field, namely, the Riemann hypothesis (one of the six unsolved millennium problems) and the Langlands program.

Venue: Okochi Hall

Event Official Language: English

Tropical Rain Forest

February 21 (Thu) at 15:30 - 17:00, 2019

Akiko Satake (Professor, Mathematical Biology Laboratory, Department of Biology, Faculty of Science, Kyushu University)

In a unique phenomenon restricted to the tropical rain forests in Southeast Asia, hundreds of plant species from dozens of families reproduce synchronously at irregular, multi-year intervals. Although several hypotheses have been proposed, the proximate environmental cues that synchronize these general flowering events are uncertain. Fortunately, accumulation of long-term data and advanced statistical and modeling techniques are starting to shed new light on phenology of tropical plants. In this talk, series of studies that integrate long-term field monitoring, gene expression analyses, and modeling will be presented.

Venue: Okochi Hall

Broadcast:#311, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: English

The 7th MACS Colloquium

February 7 (Thu) at 15:00 - 17:30, 2019

Akira Tsuchiyama (Professor, Division of Earth and Planetary Sciences, Graduate School of Science/Faculty of Science, Kyoto University)

15:00- Teatime 15:15- MACS Report Meeting FY2018 16:40- Talk by Prof. Akira Tsuchiyama The 7th MACS colloquium is supported by iTHEMS. It will be broadcasted to Wako, but if you can join the colloquium physically in Kyoto, that would be better. iTHEMS provides good confectionary at Kyoto!

Venue: Lecture room #401, Graduate School of Science Building No 6, Kyoto University

Event Official Language: Japanese