iTHEMS Colloquium

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

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

Economic Networks: a Physicist's View

October 3 (Wed) at 15:00 - 16:30, 2018

Hideaki Aoyama (Senior Visiting Scientist, iTHEMS / Professor, Graduate School of Science, Kyoto University)

Economic phenomena occur on networks formed by agents, such as firms and financial institutions. In order to understand the dynamic nature of economy, we need to understand structures of those networks and interactions between economic agents on it. In this talk, I will review several important research results on this theme, most of which uses Japanese rich, actual (not simulated) network data, including trade (production) network of about one million firms. Community structures, simulation of effect of natural disasters, new methodology required for such inquiry are some of the topics to be covered.

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

Bell's Theorem, Entanglement, Quantum Teleportation and All That

July 19 (Thu) at 16:00 - 17:30, 2018

Anthony James Leggett (Professor, University of Illinois at Urbana-Champaign, USA)

iTHEMS-CEMS Joint Colloquium. Professor Leggett is widely recognized as a world leader in the theory of low-temperature physics, and his pioneering work on superfluidity was recognized by the 2003 Nobel Prize in Physics. Abstract: One of the most surprising aspects of quantum mechanics is that under certain circumstances it does not allow individual physical systems, even when isolated, to possess properties in their own right. This feature, first clearly appreciated by John Bell in 1964, has over the last half-century been tested experimentally and found (in most people's opinion) to be spectacularly confirmed. More recently it has been realized that it permits various operations which are classically impossible, such as "teleportation" and secure-in-principle cryptography. This talk is a very basic introduction to the subject, which requires only elementary quantum mechanics.

Venue: Okochi Hall

Broadcast:#311, Computational Science Research Building / SUURI-COOL (Kyoto) / 2F Seminar Room, AIMR Main Building

Event Official Language: English

Systems Biology of Cellular Rhythms

July 2 (Mon) at 15:00 - 16:30, 2018

Albert Goldbeter (Professor, Unit of Theoretical Chronobiology, Faculty of Sciences, Université Libre de Bruxelles, Belgium)

Rhythmic phenomena occur at all levels of biological organization, with periods ranging from milliseconds to years. Among biological rhythms, circadian clocks, of a period close to 24h, play a key role as they allow the adaptation of living organisms to the alternation of day and night. Biological rhythms represent a phenomenon of temporal self-organization in the form of sustained oscillations of the limit cycle type. Mathematical models show how the emergent property of oscillatory behavior arises from molecular interactions in cellular regulatory networks, which explains why cellular rhythms represent a major research topic in systems biology. After providing an introduction to biological rhythms and their modeling, I will focus on mathematical models for two major examples of rhythmic behavior at the cellular level : the circadian clock and the cell cycle. The coupling of these rhythms allows for their synchronization and for the occurrence of more complex patterns of oscillatory behavior. I will discuss the reasons why models for cellular rhythms tend to become more complex, upon incorporating new experimental observations. The case of cellular rhythms allows us to compare the merits of simple versus complex models for the dynamics of biological systems.

Venue: Suzuki Umetaro Hall

Broadcast:#305-2, Computational Science Research Building / SUURI-COOL (Kyoto) / 2F Seminar Room, AIMR Main Building

Event Official Language: English

On the interplay between intrinsic and extrinsic instabilities of spatially localized patterns

June 7 (Thu) at 15:00 - 16:30, 2018

Yasumasa Nishiura (Professor, Advanced Institute for Materials Research (AIMR), Tohoku University)

Spatially localized dissipative structures are observed in various fields, such as neural signaling, chemical reactions, discharge patterns, granular materials, vegetated landscapes, binary convection and block copolymer nanoparticles. These patterns are much simpler than single living cells, however they seem to inherit several characteristic “living state” features, such as generation of new patterns, self-replication, switching to new dynamics via collisions and adaptive morphological changes to environments. These behaviors stem from an interplay between the intrinsic instability of each localized pattern and the strength of external signals. To understand such an interplay, we explore the global geometric interrelation amongst all relevant solution branches of a corresponding system with approximate unfolding parameters. For instance, it has been uncovered that large deformation via strong collision is mapped into the network of unstable patterns in infinite dimensional space, and that an organizing center for 1D pulse generators is a double homoclinicity of butterfly type. Large deformation of patterns is unavoidable so that a global geometric structure formed by all relevant solution branches gives us much more insight rather than conventional PDE approaches. We illustrate the impact of this approach for the case of pulse generators. We also report on the recent exciting finding, namely the formation of exotic 3D nanoparticles of block copolymers caused by the interplay between internal repulsion and affinity to external solvent, which is consistent with experimental results.

Venue: Nishina Hall

Broadcast:#305-2, Computational Science Research Building / SUURI-COOL (Kyoto)

Event Official Language: English

The Description of Biological Phenomena as Open System / Every Biological Variable has a Different Dynamic Range

April 23 (Mon) at 15:00 - 16:30, 2018

Kazuhiro Sakurada (Deputy Program Director, Medical Sciences Innovation Hub Program, RIKEN Cluster for Science, Technology and Innovation Hub (RCSTI))
Jun Seita (Unit Leader, AI based Healthcare and Medical Data Analysis Standardization Unit, RIKEN Cluster for Science, Technology and Innovation Hub (RCSTI))

The Description of Biological Phenomena as Open System / Dr. Sakurada Every Biological Variable has a Different Dynamic Range / Dr. Seita

Venue: Okochi Hall

Broadcast:6F auditorium, Computational Science Research Building / SUURI-COOL (Kyoto) / SUURI-COOL (Sendai)

Event Official Language: English