RIKEN Quantum Workshop on “Quantum-Like Modeling” in Cognitive & Social Sciences

October 11 (Fri) at 14:00 - 19:00, 2024

Recently, there has been a growing trend to consider cognitive, and social phenomena as Open Quantum Systems, and to mathematically define the fundamental principles behind them through so-called “Quantum-Like Modeling”. It has been extremely difficult to systematically explain complexities of such phenomena within humans’ cognitive traits based on classical “rational” reasoning. Quantum-Like Modeling suggests that using quantum probability calculus and its applications could be useful to rationalize such phenomena and expand previous understandings, obtained through simple linear algebra, by applying quantum formalizations. Just as physicists explored a new branch of mathematics, the theory of operators in complex Hilbert space, to describe the quantum phenomena in an effective way, considerations here will be built on the methodology and mathematical apparatus of quantum theory and directed to applications outside of physics, namely to, cognition, psychology, decision-making, economics, finances, as well as the social and political sciences. Programme 14:00~14:10 Atsushi Iriki: Introduction. Potential of quantum computing for humanities 14:10~15:10 Andrei Khrennikov: Tutorial. Ubiquitous Quantum: from genetics and biological evolution to cognition, psychology, decision making, and social science 15:10~15:40 Masanao Ozawa: Quantum Instrument -- Measurement to cognition with QC-simulation Break 16:00~16:30 Haruki Emori: Applications of quantum computers to cognitive sciences based on Quantum Instrument 16:30~17:00 Miho Fuyama: Subjective Experiences and Superposition State in Narrative Reading 17:00~17:30 General Discussion 18:00~19:00 Networking Mixer (RIKEN canteen #1) Registration Deadline September 26 (Thur), 2024 (for those attending both the workshop and networking mixer (banquet, free of charge)) October 4 (Fri), 2024 (for those attending only the workshop)

Venue: Seminar Room #359

Event Official Language: English

The laser light shed on Darwin’s ‘Abominable mystery’

October 10 (Thu) at 16:00 - 17:00, 2024

Chiharu Kato (Ph.D. Student, Department of Biological Sciences, Graduate School of Science, The University of Tokyo)

Reproductive isolation is the inability of a species to breed with related species and thus is a key to evolution of new species in flowering plants. In interspecific crosses between closely related species, a stage of pollen tube reception by female tissues of the pistil act as a pivotal hybridization barrier. Within the genus Arabidopsis, pistils of Arabidopsis thaliana can be fertilized by pollen from its relative species, but about half of the ovules reject the release of sperm from heterospecific pollen tubes and these rejected pollen tubes continue growing inside the embryo sacs (referred to as pollen tube overgrowth). A loss-of function mutant line of ARTUMES gene, encoding a subunit of the oligosaccharyltransferase complex, pollinated with heterospecific pollen shows a higher overgrowth rate than the wild type, suggesting that ARTUMES is involved in interspecific pollen tube reception. However, its molecular mechanism is largely unknown. Here, we report that some knockout lines of receptor kinases show ARTUMES mutant-like impairment in interspecific pollen tube reception, indicating that these receptor kinases might be potentially the target proteins of ARTUMES. We anticipate these receptors recognize the ligands from conspecific (self) pollen and heterospecific pollen either in the presence of ARTUMES, thus they can lead successful interspecific fertilization. We also identified ARTUMES mutant shows abnormal calcium dynamics in their female tissue during pollen tube reception. In this talk, I would like to briefly mention about how mathematical modeling can be promoting to pursue the questions regarding calcium dynamics reflecting male-female communication during fertilization. We anticipate these mechanisms that enable interspecific fertilization contribute to rapid development and diversification of flowering plants in recent geological time.

Venue: via Zoom

Event Official Language: English

Joint Seminar on cosmology and related topics

October 10 (Thu) at 14:00 - 18:00, 2024

Koki Tokeshi (Postdoctoral Researcher, Institute for Cosmic Ray Research (ICRR), The University of Tokyo)
Misako Tatsuuma (Research Scientist, iTHEMS)
Puttarak Jai-akson (Postdoctoral Researcher, iTHEMS)

Joint Seminar is a seminar series that is held regularly in Tokyo and its vicinity. The topics are on cosmology and related areas. The seminar venue alternates among the universities and research institutes in the Kanto area, and this time it is held at RIKEN. Among the 3 speakers in the event, Dr. Misako Tatsuuma and Dr. Puttarak Jai-akson from iTHEMS will give talks, together with an external speaker Dr. Koki Tokeshi (ICRR, U. Tokyo). The time table of the event is as follows: Date: October 10th (Thu), 14:30. (room will open at 14:00) Place: RIKEN iTHEMS Wako Campus, Okochi Hall Program: 14:00 Room open 14:30 Koki Tokeshi’s talk（ICRR, 45 min） 15:15 Break & free discussion（15 min） 15:30 Misako Tatsuuma’s talk（RIKEN iTHEMS, 45 min） 16:15 Break & free discussion（15 min） 16:30 Puttarak Jai-akson’s talk（RIKEN iTHEMS, 45 min） 17:15 Free Discussion（15 min） 17:30 Close (go to dinner) Titles and abstracts: 1st Speaker: Koki Tokeshi (ICRR) Title: Exact solutions in stochastic inflation Abstract: The stochastic formalism of inflation, or stochastic inflation for short, enables us to study the dynamics of large-scale primordial fluctuations in a non-perturbative way. I will present a class of all the possible exact expressions for statistical quantities such as distribution and correlation functions of a test field in the expanding universe, given that the significance of exact solutions in cosmology cannot be overemphasised. To this aim, a sequence of isospectral Hamiltonians and an underlying symmetry called shape invariance are exploited. 2nd Speaker: Misako Tatsuuma (RIKEN iTHEMS) Title: Numerical Simulations of the Strengths of Dust Aggregates in Planet Formation Abstract: Planet formation is the growth process from sub-micrometer-sized dust grains to planets larger than 10,000 km. This growth process can be broadly divided into two phases: the initial growth to kilometer-sized planetesimals, which involves the adhesion of dust grains through intermolecular forces such as van der Waals forces and hydrogen bonds, and the subsequent growth to planets, driven by gravitational forces. Currently, no unified planetesimal formation theory can fully explain both observations of protoplanetary disks, where planet formation takes place, and the exploration results of small bodies in the solar system, such as asteroids and comets, which are considered remnants of planetesimals. Constructing such a theory is the ultimate goal of planet formation studies. To investigate planetesimal formation based on the exploration results of small solar system bodies, we have used the discrete element method (DEM) to calculate the tensile and compressive strengths of dust aggregates, constructing their physically-based models that we have compared to the properties of small solar system bodies. This talk will focus on the methodologies used in these studies. 3rd Speaker: Puttarak Jai-akson (RIKEN iTHEMS) Title: Null Surfaces Through The Looking-Glass Abstract: Carrollian physics has recently become a prominent topic in theoretical physics, especially in gravitational studies and flat-space holography. Understanding Carrollian geometries and symmetries is essential to the modern interpretation of null surfaces, whether at finite distances or asymptotic infinities. In this talk, I will introduce Carrollian geometries as intrinsic to any generic null surface, and highlight the profound analogy between gravitational dynamics on null surfaces and Carrollian hydrodynamics. Additionally, I will discuss the phase space structure and symmetries associated with these geometries, shedding light on their implications for gravitational theories and potentially for holographic dualities.

Venue: Okochi Hall

Event Official Language: English

Understanding Diffusion Models by Feynman's Path Integral

October 9 (Wed) at 15:00 - 16:30, 2024

Yuji Hirono (Assistant Professor, Department of Physics, Graduate School of Science, Osaka University)

Diffusion models have emerged as powerful tools in generative modeling, especially in image generation tasks. In this talk, we introduce a novel perspective by formulating diffusion models using the path integral method introduced by Feynman for describing quantum mechanics. We find this formulation providing comprehensive descriptions of score-based diffusion generative models, such as the derivation of backward stochastic differential equations and loss functions for optimization. The formulation accommodates an interpolating parameter connecting stochastic and deterministic sampling schemes, and this parameter can be identified as a counterpart of Planck's constant in quantum physics. This analogy enables us to apply the Wentzel-Kramers-Brillouin (WKB) expansion, a well-established technique in quantum physics, for evaluating the negative log-likelihood to assess the performance disparity between stochastic and deterministic sampling schemes.

Venue: Seminar Room #359 (Main Venue) / via Zoom

Event Official Language: English

Dynamics of Phase Transitions: Between First and Second Order

October 8 (Tue) at 16:00 - 17:30, 2024

Fumika Suzuki (CNLS Postdoctoral Research Associate, T4 / Center for Nonlinear Studies, Los Alamos National Laboratory, USA)

Phase transitions are typically classified as either first-order or second-order. The formation of topological defects in second-order phase transitions is well described by the Kibble-Zurek mechanism, while nucleation theory addresses first-order phase transitions. However, certain systems, such as superconductors and liquid crystals, can exhibit “weakly first-order” phase transitions that do not fit into these established frameworks. In this presentation, I introduce a new theoretical approach that combines the Kibble-Zurek mechanism with nucleation theory to explain topological defect formation in weakly first-order phase transitions. Additionally, I will discuss nonlinear quantum phase transitions that exhibit behaviors similar to weakly first-order transitions, which can be related to experiments with ultra-cold Rydberg atoms.

Venue: Hybrid Format (3F #359 and Zoom), Seminar Room #359 (Main Venue) / via Zoom

Event Official Language: English

Application of Complex Scaling Method to Scattering Calculations of Atomic Systems

October 8 (Tue) at 13:30 - 15:00, 2024

Taishi Sano (Master's Student, Waseda University)

Based on our paper [1], this presentation will show the application of complex scaling method(CSM) to scattering calculations of atomic systems. While CSM has been extensively used to study resonance states, the application of CSM to scattering calculations was proposed recently with applications in nuclear physics. In our study, we apply the CSM scattering calculation to atomic systems and propose an effective correction to avoid the problem of slow convergence to the number of complex eigen energies. Our results with the effective correction agree well with those reported in the literature for positron scattering with the targets Ne, Ar, Kr, Xe, H, He, He+, and Li2+. In this presentation, we introduce the framework of phase-shift calculation using the CSM together with the examples of the positron scattering, and advantages and features of this approach. [This seminar is co-hosted by Few-body Systems in Physics Laboratory, RIKEN Nishina Center.]

Venue: Hybrid Format (3F #359 and Zoom), Seminar Room #359

Event Official Language: English

Dense Matter Physics and Exotic States in Neutron Stars

October 7 (Mon) at 14:00 - 15:15, 2024

Vivek Thapa (Assistant Professor, Bhawanipur Anchalik College, India)

In the presentation, I will discuss the exploration of neutron star matter using phenomenological models, focusing on how exotic particles like antikaons, hyperons as well as Delta-resonances influence the neutron star equation of state (EoS). The discussion will cover how antikaon optical potentials and kaon condensation affect the stability and structure of neutron stars, as well as the potential for hadron-quark phase transitions leading to quark matter cores in massive stars. I will also highlight the study of non-radial oscillation modes which provide insights into the internal structure and composition of neutron stars. These oscillation modes are essential for understanding neutron star asteroseismology and interpreting gravitational wave signals from neutron star mergers. By comparing theoretical predictions with observational data, including mass, radius, cooling rates, and gravitational wave detections, the presentation aims to refine constraints on the EoS and enhance our understanding of dense matter in compact stars.

Venue: Hybrid Format (3F #359 and Zoom), Seminar Room #359

Event Official Language: English

Clinical trials and standards of care: How doctors decide your medical treatment

October 2 (Wed) at 16:00 - 17:00, 2024

Catherine Beauchemin (Deputy Program Director, iTHEMS)

Ever wondered what data is considered sufficient for approval of a new drug or vaccine? In this talk, I will talk about some of the errors and shortcomings with how clinical trials are run and regulated. I will also show how the data and analyses behind clinical trials can be very poorly done. I will show one example of very bad data and analysis, but I will also show an example of the valuable information that can come out of doing a good job in presenting, interpreting, and following the data. I will highlight how the over-reliance on summarizing measures like averages and the Gaussian assumption can lead to overlooking therapies that could otherwise have been extremely effective. This talk should be of critical importance to those working in the fields of health, medical and clinical research. But this talk is about data and its analysis, and as such is also very relevant to physicists and other scientists who generate, present or analyse data as part of their research.

Venue: via Zoom / Hybrid Format (3F #359 and Zoom), Seminar Room #359

Event Official Language: English

Workshop: The 5th "Medicine and Mathematics" Workshop

September 29 (Sun) - 30 (Mon), 2024

We will have the 5th workshop on "Medicine and Math" in Kobe (hybrid style) on Sep. 29-30, 2024. For more information and registration, please visit the related links. Organizers: Akihisa Yamamoto (RIKEN iTHEMS) Tetsuo Hatsuda (RIKEN iTHEMS) Motomu Tanaka (Heidelberg Univ. / Kyoto Univ.) Hiroshi Suito (Tohoku Univ. / RIKEN iTHEMS) Eiryo Kawakami (Chiba Univ. / RIKEN R-IH) Takashi Sakajo (Kyoto Univ. / RIKEN iTHEMS)

Venue: 8F, Integrated Innovation Building (IIB) (Main Venue) / via Zoom

Event Official Language: Japanese

iTHEMS Cosmology Forum #2 - Stochastic gravitational waves: fossils from the early universe

September 27 (Fri) at 9:00 - 18:00, 2024

Keitaro Takahashi (Professor, Faculty of Advanced Science and Technology, Kumamoto University)
Kazuyuki Sugimura (Assistant Professor, Graduate School of Science, Hokkaido University)
Ryusuke Jinno (Associate Professor, Graduate School of Science, Kobe University)
Yuichiro Tada (Designated Assistant Professor, C-Lab, Department of Physics, Institute for Advanced Research, Nagoya University)

iTHEMS Cosmology Forum Workshop is a series of short workshops, each focused on an emerging topics in cosmology. The targeted audience is cosmologists, high-energy physicists and astronomers interested in learning about the subject, not just those who have already worked on the topic. The goal of the workshop is to provide working knowledge of the topic and leave dedicated time for discussions to encourage mutual interactions among participants. The second workshop is devoted to explanations of the stochastic gravitational wave background (SGWB). The SGWB is a significant detection of GW from pulsar timing arrays. The origin of this background could be either supermassive black holes or primordial. Surprisingly, both of these early Universe mechanisms are not well understood. This one-day workshop gathers both the observational and theoretical aspects of this growing topic. The workshop will be in English. The workshop venue will be either at Main Research Building #435-437 or at Okochi Hall, and we will decide and announce which one will be actually used after the registration is closed. The workshops are organised by the iTHEMS Cosmology Forum working group, which is the successor of the Dark Matter Working Group at RIKEN iTHEMS. Invited Speakers: Keitaro Takahashi (Kumamoto University) TBA Kazuyuki Sugimura (Hokkaido University) Supermassive black hole formation Ryusuke Jinno (Kobe University) First-order phase transitions and gravitational wave production in the early Univers Yuichiro Tada (Nagoya University) Scalar-induced gravitational waves as a cosmological phonograph Time table: 09:00-09:30 -- Opening remarks and coffee 09:30-10:45 -- Takahashi (keynote) 10:45-11:45 -- Sugimura 11:45-13:30 -- Lunch time 13:30-14:30 -- Jinno 14:30-15:30 -- Discussion and coffee 15:30-16:30 -- Tada 16:30-17:30 -- Panel Discussion Organisers: Kohei Hayashi, Nagisa Hiroshima, Derek Inman, Amaury Micheli, Ryo Namba

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

Event Official Language: English

Organizational meeting 4

September 26 (Thu) at 16:00 - 17:00, 2024

This the semi-regular opportunity for iTHEMS Biology members to discuss their current research progress and/or difficulties and/or research questions. Anyone is welcome to join. It will be held in hybrid form.

Venue: via Zoom / Hybrid Format (3F #359 and Zoom), Seminar Room #359

Event Official Language: English

Evolution and origin of complex genetic organisms

September 19 (Thu) at 16:00 - 17:00, 2024

Thomas Hitchcock (Special Postdoctoral Researcher, iTHEMS)

Whilst the standard Mendelian rules of inheritance are the most familiar to most researchers, and common across many groups of organisms, a large minority of animals diverge from this. Included in this are eusocial groups such as ants, wasps, bees and termites. These creatures can be thought of not only as groups of individuals (workers, queens, kings), but also as a single complex genetic organism (a “superorganism”). Amongst these groups a wide array of genetic and mating systems have also emerged. I first describe some of the variation in some of the genetic systems we see, and then outline some plans for models of molecular evolution in these species. I'll discuss how these groups may enable some non-standard forms of meiotic drive, which in turn may help explain the origin of some of the unusual genetic features and systems that we observe.

Venue: Hybrid Format (3F #359 and Zoom), Main Research Building

Event Official Language: English

Renormalization Group Approach for Machine Learning Hamiltonian

September 10 (Tue) at 15:00 - 17:00, 2024

Misaki Ozawa (CNRS Researcher, Laboratory for Interdisciplinary Physics (LIPhy), Université Grenoble Alpes, France)

We develop a multiscale approach to estimate high-dimensional probability distributions. Our approach applies to cases in which the energy function (or Hamiltonian) is not known from the start. Using data acquired from experiments or simulations we can estimate the underlying probability distribution and the associated energy function. Our method—the wavelet-conditional renormalization group (WCRG)—proceeds scale by scale, estimating models for the conditional probabilities of “fast degrees of freedom” conditioned by coarse-grained fields, which allows for fast sampling of many-body systems in various domains, from statistical physics to cosmology. Our method completely avoids the “critical slowing-down” of direct estimation and sampling algorithms. This is explained theoretically by combining results from RG and wavelet theories, and verified numerically for the Gaussian and φ4-field theories, as well as weak-gravitational-lensing fields in cosmology. Misaki Ozawa obtained his Ph.D. in 2015 from the University of Tsukuba. He did his first postdoc at the University of Montpellier in France. He then moved to Ecole Normale Supérieure (ENS) Paris as the second postdoc. Currently, he is a CNRS permanent researcher at Grenoble Alpes Univeristy in France. His background is in the physics of disordered systems such as glasses and spin glasses. He is also working on interdisciplinary studies between statistical physics and machine learning.

Venue: #359, 3F, Seminar Room #359 / via Zoom

Event Official Language: English

A model to unify the theory of speciation

September 5 (Thu) at 16:00 - 17:00, 2024

José Said Gutiérrez-Ortega (Special Postdoctoral Researcher, iTHEMS)

Speciation, the process by which new species originate, occurs due to geographic (physical distance), ecological (different background environments), and historical (divergence time) factors that promote reproductive isolation among lineages. However, we don’t know how these factors interplay; therefore, our empirical and theoretical knowledge about speciation is limited, fragmented, and lacks unification. To fill this knowledge gap, I propose a model and an experiment that treats speciation as a continuum of the interplay between geographic and ecological factors. Empirical evidence has shown that the extremes of this continuum produce high evolutionary rate (faster speciation), while I expect that intermediate values in the interplay continuum would produce reduced evolutionary rates. I expect this seminar can open opportunities for collaboration.

Venue: via Zoom / Seminar Room #359

Event Official Language: English

RIKEN - LBNL Workshop on Quantum Information Science

September 3 (Tue) - 6 (Fri), 2024

This international workshop will bring together researchers worldwide to discuss and collaborate on the latest developments in quantum technologies and quantum computing. Other focus areas will be algorithms, hybrid classical - quantum computing, error mitigation, and applications in physics and chemistry. With an emphasis to galvanize the participants into future collaborations, in addition to presentations on recent trends, the workshop will dedicate time in the afternoons for facilitated brainstorming and planning sessions.

Venue: Lawrence Berkeley National Laboratory (Berkeley, California)

Event Official Language: English

Visit by MACS SG Students

September 2 (Mon) - 3 (Tue), 2024

Monday, September 2nd 13:20–13:30: Opening 13:30–13:40: Self-introductions 13:40–14:10: Introduction to iTHEMS 14:10–14:30: Coffee Break 14:30–15:30: Seminar by iTHEMS Researcher (Dr. Moriwaki) 16:30–18:00: Laboratory Visit (Kazama Lab) 18:30–20:00: Research Presentation/ Discussion Session Tuesday, September 3rd 10:00–10:20: Tour of iTHEMS Facilities 10:40–12:10: Laboratory Visit (Tatara Lab) 12:20–13:20: Lunch/Coffee Break 13:30–15:00: Laboratory Visit (Tamagawa Lab) 15:30–17:00: Laboratory Visit (Isomura Lab) 17:20–17:30: Closing

Venue: Seminar Room #359

Event Official Language: Japanese

NCTS-iTHEMS Joint Workshop on Matters to Spacetime: Symmetries and Geometry

August 26 (Mon) - 29 (Thu), 2024

The National Center for Theoretical Sciences (NCTS) and the Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS) at RIKEN have long maintained a collaborative relationship, even before the Memorandum of Understanding was signed in December, 2022. This partnership has successfully facilitated joint activities in high energy physics over recent years. As the impact of the COVID-19 pandemic wanes, we are excited to announce the inaugural joint workshops focusing on condensed matter physics and (quantum) gravity. These workshops are designed to foster international collaborations and stimulate interdisciplinary research. We are pleased to invite you to the 2024 NCTS-iTHEMS Workshop on Matters to Spacetime: Symmetries and Geometry, to be held from August 26 (Monday) to August 29 (Thursday), at the National Center for Theoretical Sciences, located on the campus of National Taiwan University (NTU) in Taipei, Taiwan. This workshop will feature presentations on the latest research findings, foster discussions to spark new ideas, and provide opportunities for initiating collaborative projects. While we strongly encourage in-person attendance to maximize engagement and interaction, an online platform will also be available to accommodate participants who are unable to attend physically.

Venue: NCTS Physics Lecture Hall, 4th Floor, Cosmology Hall, National Taiwan University

Event Official Language: English

Chromatophore patterns, packing, and scaling on a growing squid

August 20 (Tue) at 16:00 - 17:00, 2024

Robert Ross (Interdisciplinary Postdoctoral Researcher, Biological Complexity Unit / Computational Neuroethology Unit, Okinawa Institute of Science and Technology Graduate University (OIST))

Many biological patterns are formed during growth, and various modeling approaches have repeatedly shown that growth can substantially impact pattern formation. However, experimental testing of these ideas has been limited, largely due to the difficulty in precisely measuring organism growth while simultaneously tracking the dynamics of pattern formation. To address this, we turned to the skin of the oval squid. The oval squid grows rapidly, hatching with a length of approximately 16mm and reaching 90mm within 3 months. Throughout development, its skin is populated by pigment-filled cells called chromatophores. Following insertion into the skin, chromatophores do not move. This means that squid chromatophores, besides being the constitutive elements of a point pattern, can also function as reference points to precisely determine skin growth. For the more biologically-minded, I will explain how the chromatophore pattern emerges through the interplay of growth and decreasing chromatophore growth rates. For those who lean physics, I will talk about how due to the combination of volume exclusion and growth, chromatophores exhibit a scaling in which relative density fluctuations grow with spatial scale, akin to a critical system.

Venue: Hybrid Format (3F #359 and Zoom), Seminar Room #359

Event Official Language: English

What will Happen to iTHEMS⊗Masason Foundation Members?

August 2 (Fri) at 13:30 - 17:30, 2024

Venue: Seminar Room #359

Event Official Language: English

Social behavior and social engineering in bacteria

August 1 (Thu) at 16:00 - 17:00, 2024

Ashleigh Griffin (Professor, Department of Biology, University of Oxford, UK)

This year is the 60th anniversary of WD Hamilton’s seminal paper in which he outlined his theory of inclusive fitness and showed how it could be used to understand altruism in the social insects. In this talk, I will describe efforts made to use his theory to understand social behavior in bacteria. And I’ll go on to explore the potential of using these insights to tackle problems of antibiotic resistance in infections.

Venue: Seminar Room #359 / via Zoom

Event Official Language: English