Lecture
49 events
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Lecture
9th QGG Intensive Lectures – Correlation Effects in Quantum Many-Body Systems: Some Prototypical Examples in Condensed Matter Physics
November 19 (Wed) - 20 (Thu) 2025
Norio Kawakami (Deputy Director, Fundamental Quantum Science Program, TRIP Headquarters, RIKEN)
The ninth installment of the Intensive Lecture Series, organized by the Quantum Gravity Gatherings (QGG) study group at RIKEN iTHEMS, will feature Prof. Norio Kawakami from the Fundamental Quantum Science Program (FQSP) under RIKEN's Transformative Research Innovative Platform (TRIP). Over the course of two days, Prof. Kawakami will deliver a lecture series on quantum many-body systems. In recent years, insights from quantum many-body physics have become central to research in quantum gravity, where correlation effects induced by gravity play nontrivial roles. By bridging perspectives from gravitational physics and quantum many-body dynamics, one hopes to understand how macroscopic spacetime and its geometric properties emerge from the collective behavior of quantum constituents at microscopic scales. In this lecture series, Prof. Kawakami will introduce the fundamental properties of correlation effects through representative examples in condensed matter physics. A distinctive aspect of this event is its joint organization with the Fundamental Quantum Science Program (FQSP) at RIKEN. The goal is to further strengthen connections between the quantum gravity, condensed matter, and quantum information communities. 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. Abstract: Some examples of theoretical methods to treat strongly correlated systems in condensed matter physics are explained. We start with the Kondo effect, which is one of the most fundamental quantum many-body problems and has been intensively studied to date in a wide variety of topics such as dilute magnetic alloys, heavy fermion systems, quantum dot systems, etc. Dynamical mean-field theory (DMFT) is then introduced, which enables us to systematically treat strongly correlated materials such as a Mott insulator. It is shown that the essence of DMFT is closely related to the Kondo effect. Furthermore, we explain how to apply conformal field theory (CFT) to treat correlation effects in one-dimensional electron systems.
Venue: #435-437, 4F, Main Research Building
Event Official Language: English
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Lecture
Lectures on Neutron Star Structure IV
October 28 (Tue) 15:30 - 17:00, 2025
Mark Alford (Professor, Washington University in St. Louis, USA)
This is a lecture series by Prof. Mark Alford (Washington University in St. Louis) on the structure of neutron stars. Oct. 7 (Tues), 15:30-17:00 Lecture I : Quark matter: the high-density frontier The densest predicted state of matter is color-superconducting quark matter, which has some affinities to electrical superconductors, but a much richer phase structure because quarks come in many varieties. This form of matter may well exist in the core of compact stars, and the search for signatures of its presence is currently proceeding. I will review the nature of color-superconducting quark matter, and discuss some ideas for finding it in nature. Oct. 14 (Tues), 15:30-17:00 Lecture II: Solid quark matter I will review three ways in which quark matter can occur in a solid phase, where translational invariance is broken by some sort of crystalline structure. These include a color superconductor of the Fulde-Ferrell-Larkin-Ovchinnikov type, mixed phases that can arise at a nuclear/quark matter interface, and the strangelet crystal crust of a strange star. Oct. 21 (Tues), 15:30-17:00 Lecture III: Dissipation in neutron star mergers In a neutron star merger, nuclear matter experiences dramatic changes in temperature and density that happen in milliseconds. Mergers therefore probe dynamical properties that may help us uncover the phase structure of ultra-dense matter. I will describe some of the relevant material properties, focusing on flavor equilibration and its consequences such as bulk viscosity and damping of oscillations. Oct. 28 (Tues), 15:30-17:00 Lecture IV: Neutrinos in dense matter: beyond modified Urca Neutrino absorption and emission (the "Urca process") is an essential aspect of the formation and cooling of neutron stars and of the dynamics of neutron star mergers. In this talk I will describe the traditional way of calculating Urca rates, explain its shortfalls, and propose an alternative approach, the nucleon width approximation.
Venue: Seminar Room #359, Seminar Room #359 (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Lectures on Neutron Star Structure III
October 21 (Tue) 15:30 - 17:00, 2025
Mark Alford (Professor, Washington University in St. Louis, USA)
This is a lecture series by Prof. Mark Alford (Washington University in St. Louis) on the structure of neutron stars. Oct. 7 (Tues), 15:30-17:00 Lecture I : Quark matter: the high-density frontier The densest predicted state of matter is color-superconducting quark matter, which has some affinities to electrical superconductors, but a much richer phase structure because quarks come in many varieties. This form of matter may well exist in the core of compact stars, and the search for signatures of its presence is currently proceeding. I will review the nature of color-superconducting quark matter, and discuss some ideas for finding it in nature. Oct. 14 (Tues), 15:30-17:00 Lecture II: Solid quark matter I will review three ways in which quark matter can occur in a solid phase, where translational invariance is broken by some sort of crystalline structure. These include a color superconductor of the Fulde-Ferrell-Larkin-Ovchinnikov type, mixed phases that can arise at a nuclear/quark matter interface, and the strangelet crystal crust of a strange star. Oct. 21 (Tues), 15:30-17:00 Lecture III: Dissipation in neutron star mergers In a neutron star merger, nuclear matter experiences dramatic changes in temperature and density that happen in milliseconds. Mergers therefore probe dynamical properties that may help us uncover the phase structure of ultra-dense matter. I will describe some of the relevant material properties, focusing on flavor equilibration and its consequences such as bulk viscosity and damping of oscillations. Oct. 28 (Tues), 15:30-17:00 Lecture IV: Neutrinos in dense matter: beyond modified Urca Neutrino absorption and emission (the "Urca process") is an essential aspect of the formation and cooling of neutron stars and of the dynamics of neutron star mergers. In this talk I will describe the traditional way of calculating Urca rates, explain its shortfalls, and propose an alternative approach, the nucleon width approximation.
Venue: Seminar Room #359 (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Lectures on Neutron Star Structure II
October 14 (Tue) 15:30 - 17:00, 2025
Mark Alford (Professor, Washington University in St. Louis, USA)
This is a lecture series by Prof. Mark Alford (Washington University in St. Louis) on the structure of neutron stars. Oct. 7 (Tues), 15:30-17:00 Lecture I: Quark matter: the high-density frontier The densest predicted state of matter is color-superconducting quark matter, which has some affinities to electrical superconductors, but a much richer phase structure because quarks come in many varieties. This form of matter may well exist in the core of compact stars, and the search for signatures of its presence is currently proceeding. I will review the nature of color-superconducting quark matter, and discuss some ideas for finding it in nature. Oct. 14 (Tues), 15:30-17:00 Lecture II: Solid quark matter I will review three ways in which quark matter can occur in a solid phase, where translational invariance is broken by some sort of crystalline structure. These include a color superconductor of the Fulde-Ferrell-Larkin-Ovchinnikov type, mixed phases that can arise at a nuclear/quark matter interface, and the strangelet crystal crust of a strange star. Oct. 21 (Tues), 15:30-17:00 Lecture III: Dissipation in neutron star mergers In a neutron star merger, nuclear matter experiences dramatic changes in temperature and density that happen in milliseconds. Mergers therefore probe dynamical properties that may help us uncover the phase structure of ultra-dense matter. I will describe some of the relevant material properties, focusing on flavor equilibration and its consequences such as bulk viscosity and damping of oscillations. Oct. 28 (Tues), 15:30-17:00 Lecture IV: Neutrinos in dense matter: beyond modified Urca Neutrino absorption and emission (the "Urca process") is an essential aspect of the formation and cooling of neutron stars and of the dynamics of neutron star mergers. In this talk I will describe the traditional way of calculating Urca rates, explain its shortfalls, and propose an alternative approach, the nucleon width approximation.
Venue: Seminar Room #359 (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Lectures on Neutron Star Structure I
October 7 (Tue) 15:30 - 17:00, 2025
Mark Alford (Professor, Washington University in St. Louis, USA)
This is a lecture series by Prof. Mark Alford (Washington University in St. Louis) on the structure of neutron stars. Oct. 7 (Tues), 15:30-17:00 Lecture I: Quark matter: the high-density frontier The densest predicted state of matter is color-superconducting quark matter, which has some affinities to electrical superconductors, but a much richer phase structure because quarks come in many varieties. This form of matter may well exist in the core of compact stars, and the search for signatures of its presence is currently proceeding. I will review the nature of color-superconducting quark matter, and discuss some ideas for finding it in nature. Oct. 14 (Tues), 15:30-17:00 Lecture II: Solid quark matter I will review three ways in which quark matter can occur in a solid phase, where translational invariance is broken by some sort of crystalline structure. These include a color superconductor of the Fulde-Ferrell-Larkin-Ovchinnikov type, mixed phases that can arise at a nuclear/quark matter interface, and the strangelet crystal crust of a strange star. Oct. 21 (Tues), 15:30-17:00 Lecture III: Dissipation in neutron star mergers In a neutron star merger, nuclear matter experiences dramatic changes in temperature and density that happen in milliseconds. Mergers therefore probe dynamical properties that may help us uncover the phase structure of ultra-dense matter. I will describe some of the relevant material properties, focusing on flavor equilibration and its consequences such as bulk viscosity and damping of oscillations. Oct. 28 (Tues), 15:30-17:00 Lecture IV: Neutrinos in dense matter: beyond modified Urca Neutrino absorption and emission (the "Urca process") is an essential aspect of the formation and cooling of neutron stars and of the dynamics of neutron star mergers. In this talk I will describe the traditional way of calculating Urca rates, explain its shortfalls, and propose an alternative approach, the nucleon width approximation.
Venue: Seminar Room #359 (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Lectures on General Probabilistic Theories: From Introduction to Research Participation
October 6 (Mon) - 9 (Thu) 2025
Hayato Arai (JSPS Research Fellow, Graduate School of Arts and Sciences, The University of Tokyo)
(The deadline of the registration is on Sep 30.) 100 years have passed since quantum mechanics was born. The mathematical model has been describing the physical world remarkably well. However, the foundations of this model still remain unclear. A comprehensive understanding of quantum theory, including its foundations, is becoming even more important in an era where the demands of realizing quantum information technologies pose significant theoretical and experimental challenges. The framework of General Probabilistic Theories (GPTs) is a modern approach to the foundations of quantum theory. It deals with mathematical generalizations of both classical and quantum theories and has attracted increasing attention in recent years. Roughly speaking, research on GPTs has three major objectives: characterizing the models of classical and quantum theories, investigating the fundamental limits of physical and information-theoretic properties arising from operational requirements, and deepening our understanding of the mathematical structures underlying classical and quantum theories. The studies of GPTs have provided many new perspectives on these topics. However, at the same time, there remain many important open problems in the field. For this reason, more researchers are encouraged to enter and contribute to research on GPTs. This intensive three-day lecture series is designed to provide researchers and graduate students with the essential knowledge necessary for research on GPTs, starting from an introduction to the subject. The lectures will cover the mathematical foundations, physical and information-theoretic concepts, and both the established results and future directions of GPT research. The 1st day will present the necessary mathematical structures, including convex geometry, positive cones, and the operational formulation of probabilistic models. The 2nd day will explore composite systems, information-theoretic quantities, symmetries, and Euclidean Jordan algebras. The 3rd day will survey key results on discrimination and communication tasks, the characterization of classical and quantum theories, and open problems that connect GPTs to quantum information science and beyond. Note: The content of each lecture may extend into the next slot or be covered earlier, depending on the pace of discussion and participant questions. The 1st day (6th Oct.): Mathematical Introduction to GPTs Venue: Large Meeting Room, 2F, Wako Welfare & Conference Building 10:30-12:00 Lecture 1 (Introduction and Mathematics on Positive Cones) 12:00-13:30 Lunch time 13:30-15:00 Lecture 2 (Mathematics on Positive Cones) 15:00-15:30 Coffee break 15:30-17:00 Lecture 3 (Introduction to General Models and Relation between Operational Probability Theories) The 2nd day (7th Oct.): Physical and Information Theoretical Concepts in GPTs Venue: Large Meeting Room, 2F, Wako Welfare & Conference Building 10:30-12:00 Lecture 4 (Composite Systems in GPTs) 12:00-13:30 Lunch time 13:30-15:00 Lecture 5 (Information Quantities) 15:00-15:30 Coffee break 15:30-17:00 Lecture 6 (Dynamics, Symmetry, and Euclidean Jordan Algebras) The 3rd day (8th Oct): Previous and Future Studies in GPTs Venue: Meeting Room 435-437, 4F, Wako Main Research Building 10:30-12:00 Lecture 7 (Discrimination and Communication Tasks) 12:00-13:30 Lunch time 13:30-15:00 Lecture 8 (Characterization of Classical and Quantum Theories) 15:00-15:30 Coffee break 15:30-17:00 Lecture 9 (Other Topics, Open Problems, and Future Directions) 18:00- Dinner The day of no lecture (9th Oct): Open Discussion and Q&A Research discussions will take place between the lecturer and participants in areas such as the hallways on the 3rd and 4th floors of the Main Research Bldg, RIKEN Wako Campus.
Venue: Welfare and Conference Bldg. 2F Meeting Room, RIKEN Wako Campus / #435-437, Main Research Building
Event Official Language: English
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Lecture
8th QGG Intensive Lecture: Quantum reference frames and their applications in high-energy physics
September 24 (Wed) - 26 (Fri) 2025
Philipp Höhn (Assistant Professor, Qubits and Spacetime Unit, Okinawa Institute of Science and Technology Graduate University (OIST))
Quantum reference frames (QRFs) are a universal tool for dealing with symmetries in quantum systems. Roughly speaking, they are internal subsystems that transform in some non-trivial way under the symmetry group of interest and constitute the means for describing quantum systems from the inside in purely relational terms. QRFs are thus crucial for describing and extracting physics whenever no external reference frame for the symmetry group is available. This is in particular the case when the symmetries are gauge, as in gauge theory and gravity, where QRFs arise whenever building physical observables. The choice of internal QRF is typically non-unique, giving rise to a novel quantum form of covariance of physical properties under QRF transformations. This lecture series will explore this novel perspective in detail with a specific emphasis on applications in high-energy physics and gravity. I will begin by introducing QRFs in mechanical setups and explain how they give rise to quantum structures of covariance that mimic those underlying special relativity. I will explain how this leads to subsystem relativity, the insight that different QRF decompose the total system in different ways into gauge-invariant subsystems, and how this leads to the QRF dependence of correlations, entropies, and thermal properties. We will then explore how relational dynamics in Hamiltonian constrained systems and the infamous "problem of time" can be addressed with clocks identified as temporal QRFs. In transitioning to the field theory setting, we will first consider hybrid scenarios, where QRFs are quantum mechanical, but the remaining degrees of freedom are quantum fields including gravitons. I will explain how this encompasses the recent discussion of "observers", generalized entropies, and gravitational von Neumann algebras by Witten et al. and how subsystem relativity leads to the conclusion that gravitational entanglement entropies are observer dependent. We will then discuss the classical analog of QRFs in gauge theory and gravity and how they can be used to build gauge-invariant relational observables and to describe local subsystems. This will connect with discussions on edge and soft modes in the literature, the former of which turn out to be QRFs as well. This has bearing on entanglement entropies in gauge theories, which I will describe on the lattice, providing a novel relational construction that overcomes the challenges faced by previous constructions, which yielded non-distillable contributions to the entropy and can be recovered as the intersection of "all QRF perspectives". Finally, I will describe how the classical discussion of dynamical reference frames can be used to build a manifestly gauge-invariant path integral formulation that opens up novel relational perspectives on effective actions and the renormalization group in gravitational contexts, which is typically plagued by a lack of manifest diffeomorphism-invariance. I will conclude with open questions and challenges in the field. Program: September 24 10:15 - 10:30 Registration and reception with coffee 10:30 - 12:00 Lecture 1 12:00 - 13:30 Lunch 13:30 - 15:00 Lecture 2 15:00 - 16:00 Coffee break 16:00 - 17:00 Lecture 3 17:10 - 18:10 Short talk session 18:20 - 21.00 Banquet September 25 10:15 - 10:30 Morning discussion with coffee 10:30 - 12:00 Lecture 4 12:00 - 13:30 Lunch 13:30 - 15:00 Lecture 5 15:00 - 16:00 Coffee break 16:00 - 17:00 Lecture 6 17:10 - 18:10 Short talk session September 26 10:15 - 10:30 Morning discussion with coffee 10:30 - 12:00 Lecture 7 12:00 - 13:30 Lunch 13:30 - 15:00 Lecture 8 15:00 - 16:00 Coffee break 16:00 - 17:00 Lecture 9 & Closing
Venue: #435-437, 4F, Main Research Building
Event Official Language: English
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Lecture
Matter-Wave Interferometry in the Limit of High Mass and Internal Complexity, and the Relevance of Optomechanical Sources
December 16 (Mon) 10:00 - 11:00, 2024
Markus Arndt (Professor, University of Vienna, Austria)
The seminar will feature a lecture by Professor Markus Arndt from the University of Vienna. Following the lecture, starting at approximately 11:00 AM, Nobuyuki Matsumoto will give a brief introduction to his research and conduct a tour of his laboratory. Hosted by Gakushuin University Co-hosted by iTHEMS
Venue: Room 007, South Building 4, Gakushuin University
Event Official Language: English
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Lecture
The 6th Special Online Class for Junior and Senior High School Students: Hot Science in Kobe Right Now
November 2 (Sat) 10:30 - 14:30, 2024
Genshiro Sunagawa (Team Leader, Laboratory for Hibernation Biology, RIKEN Center for Biosystems Dynamics Research (BDR))
Kento Sato (Team Leader, High Performance Big Data Research Team, RIKEN Center for Computational Science (R-CCS))
Kyosuke Adachi (Research Scientist, RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS))
Safiye Esra Sarper (Special Postdoctoral Researcher, Laboratory for Developmental Morphogeometry, RIKEN Center for Biosystems Dynamics Research (BDR))The RIKEN conducts a wide variety of research. In this session, four researchers working at the Kobe Campus in the fields of mathematical science, information science, and biology will present their work. From iTHEMS, Research Scientist Kyosuke Adachi will introduce his research, which aims to uncover the mechanisms of collective motion using physics and computers. For those interested in participating, please check the event website via the related link for instructions on how to attend.
Venue: via Zoom
Event Official Language: Japanese
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Lecture
Differential Topology Seminar: Rigidity and Flexibility of Isometric Embeddings
July 16 (Tue) 15:00 - 16:30, 2024
Dominik Inauen (Academic Staff, University of Leipzig, Germany)
The problem of embedding abstract Riemannian manifolds isometrically (i.e. preserving the lengths) into Euclidean space stems from the conceptually fundamental question of whether abstract Riemannian manifolds and submanifolds of Euclidean space are the same. As it turns out, such embeddings have a drastically different behaviour at low regularity (i.e. C1) than at high regularity (i.e. C2). For example, by the famous Nash--Kuiper theorem it is possible to find C1 isometric embeddings of the standard 2-sphere into arbitrarily small balls in R3, and yet, in the C2 category there is (up to translation and rotation) just one isometric embedding, namely the standard inclusion. Analoguous to the Onsager conjecture in fluid dynamics, one might ask if there is a sharp regularity threshold in the Holder scale which distinguishes these flexible and rigid behaviours. In my talk I will review some known results and argue why the Holder exponent 1/2 can be seen as a critical exponent in the problem.
Venue: ＃609, Department of Mathematics, Faculty of Science Bldg. No. 6, , Kyoto University
Event Official Language: English
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Lecture
Obstructions to Lagrangian surgery
June 27 (Thu) 15:00 - 17:00, 2024
Emmy Murphy (Professor, Princeton University, USA)
Given a Lagrangian immersion with a transverse double point, we can surger this point to obtain an embedded Lagrangian with more complicated topology. As a classical example, both the Clifford and Chekanov tori in C2 are obtained via Lagrangian surgery on a immersed sphere called the Whitney sphere. In the talk we'll discuss a Floer-theoretic obstruction to this: that is, showing that a Lagrangian cannot be realized as a surgery. An interesting dilemma is that PH invariants of an immersed Lagrangian itself cannot detect the fact that it is immersed. Instead, we have to consider families of Floer invariants coming from all possible surgeries, and use properties specific to SFT Lagrangian cobordism maps.
Venue: Room 201 in Building No.15, RIMS, Kyoto University
Event Official Language: English
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Lecture
Liouville symmetry groups and pseudo-isotopies
June 25 (Tue) 17:00 - 18:30, 2024
Emmy Murphy (Professor, Princeton University, USA)
Even though Cn is the most basic symplectic manifold, when n>2 its compactly supported symplectomorphism group remains mysterious. For instance, we do not know if it is connected. To understand it better, one can define various subgroups of the symplectomorphism group, and a number of Serre fibrations between them. This leads us to the Liouville pseudo-isotopy group of a contact manifold, important for relating (for instance) compactly supported symplectomorphisms of Cn, and contacomorphisms of the sphere at infinity. After explaining this background, the talk will focus on a new result: that the pseudo-isotopy group is connected, under a Liouville-vs-Weinstein hypothesis.
Venue: Room 056, Graduate School of Mathematical Sciences, The University of Tokyo (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Rigidity and Flexibility of Isometric Embeddings
June 20 (Thu) 17:00 - 18:30, 2024
Dominik Inauen (Academic Staff, University of Leipzig, Germany)
The problem of embedding abstract Riemannian manifolds isometrically (i.e. preserving the lengths) into Euclidean space stems from the conceptually fundamental question of whether abstract Riemannian manifolds and submanifolds of Euclidean space are the same. As it turns out, such embeddings have a drastically different behaviour at low regularity (i.e. C^1) than at high regularity (i.e. C^2). For example, by the famous Nash--Kuiper theorem it is possible to find C1 isometric embeddings of the standard 2-sphere into arbitrarily small balls in R^3, and yet, in the C^2 category there is (up to translation and rotation) just one isometric embedding, namely the standard inclusion. Analoguous to the Onsager conjecture in fluid dynamics, one might ask if there is a sharp regularity threshold in the Holder scale which distinguishes these flexible and rigid behaviours. In my talk I will review some known results and argue why the Holder exponent 1/2 can be seen as a critical exponent in the problem.
Venue: Graduate School of Mathematical Sciences, The University of Tokyo
Event Official Language: English
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Lecture
An introduction to the exact WKB analysis via the hypergeometric differential equation
February 19 (Mon) - 22 (Thu) 2024
Takashi Aoki (Professor Emeritus, Faculty of Science and Engineering, Kinki University)
This is an introductory course to the exact WKB analysis. Firstly we review some basic facts concerning formal power series and WKB solutions. Secondly we give an overview of the connection formulas for WKB solutions to ordinary differential equations of second order with a large parameter. Next, after recalling some classical theory for the Airy equation and the Gauss hypergeometric differential equation, we show how the exact WKB analysis is used for these equations and what are obtained. One of the main results to be presented in this course is the relation the between the classical hypergeometric function and the Borel resummed WKB solutions to the hypergeometric differential equation with a large parameter. Some applications and recent topics are also given. [Schedule (Tentative)] Day 1 10:00 - 11:30 Lecture 1 14:00 - 16:00 Lecture 2 Day 2 10:00 - 11:30 Lecture 3 14:00 - 16:00 Lecture 4 Day 3 10:00 - 11:30 Lecture 5 14:00 - 16:00 Lecture 6 Day 4 10:00 - 11:30 Lecture 7 14:00 - 16:00 Lecture 8
Venue: Seminar Room #359 (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Introduction to Effective Field Theory and Many-Body Problems
December 27 (Wed) - 28 (Thu) 2023
Masaru Hongo (Assistant Professor, Department of Physics, Faculty of Science, Niigata University)
Quantum field theory (QFT) has been formulated as a theoretical tool to describe elementary particles and nuclei. However, after introducing the concept of "effective field theory," QFT has been providing a general and powerful theoretical framework for describing various universal phenomena in broader range of physical systems, including condensed matter physics and statistical physics. In this lecture, we will explore the basic aspects of field theory by employing it to address quantum many-body problems in simple nonrelativistic systems. The topics covered will include: Lecture 1: Low-energy scattering and renormalization in quantum mechanics Lecture 2: Effective field theory of low-energy scattering Lecture 3: Spontaneous symmetry breaking in weakly-interacting bose gas Lecture 4: Effective field theory of superfluid Lecture 5: Introduction to in-medium potential Lecture 6: Complex-valued in-medium potential between heavy impurities in ultracold atoms The aim is to provide an introductory overview and explanation of basics concepts in field theory. Schedule: Wed., Dec. 27 10:00 - 11:30: Lecture 1 13:00 - 14:30: Lecture 2 15:00 - 16:30: Lecture 3 Thur., Dec. 28 10:00 - 11:30: Lecture 4 13:00 - 14:30: Lecture 5 15:00 - 16:30: Lecture 6
Venue: Hybrid Format (3F #359 and Zoom), Main Research Building
Event Official Language: English
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Lecture
Rapid development of cold-atom quantum computers and their prospect
December 26 (Tue) 13:30 - 17:00, 2023
Takafumi Tomita (Assistant Professor, Photo-Molecular Science, Institute for Molecular Science)
Note for participants: For on-site participants, please register via the registration form. For online participants finding the Zoom link, you can get it after filling the registration form. Program: 13:30-15:00 Lecture 1 15:00-15:30 Coffee break 15:30-17:00 Lecture 2 Abstract: In this talk, I will give an overview of the recent rapid progress of cold-atom quantum computers. In a cold-atom quantum computer, a laser-cooled atomic gas in a vacuum chamber is captured with a two-dimensional trap array called an optical tweezers array, which is an array of tightly focused laser beams. An array of cold single atoms thus created is initialized, gate operated, and readout with other laser beams. Because of its controllability and scalability, the cold-atom quantum computer has been attracting much attention, as one of the most promising candidates in the race to develop quantum-computer hardware. I will describe the characteristics and development trends of the cold-atom hardware, as well as the development of a cold-atom quantum computer at Institute for Molecular Science including the realization of an ultrafast quantum gate using ultrashort laser pulses.
Venue: #435-437, 4F, Main Research Building (Main Venue) / via Zoom
Event Official Language: English
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Lecture
Transforming Industries and Society: The Power of Advanced Math and AI Technologies
December 12 (Tue) 16:30 - 18:00, 2023
Hirokazu Anai (Principal Research Director, FUJITSU RESEARCH, FUJITSU Ltd.)
In this talk, we will review the history and the latest trends in artificial intelligence (AI) and mathematical technologies in recent years. We will also introduce various real-world problem-solving efforts that utilize state-of-the-art mathematics and artificial intelligence technology. Additionally, we will explore the role of mathematical and AI technologies and the social value they bring, while providing examples of their applications in a wide range of fields, such as manufacturing, disaster prevention, medical care, and institutional design in society. Furthermore, we will consider the thinking and skills required to address industrial and social issues using mathematical and AI technologies. The technologies that will be discussed in this talk include the following keywords: mathematical modeling, simulation, optimization, deep learning, topological data analysis, causal discovery, game theory, matching theory, and social mathematics.
Venue: Okochi Hall (Main Venue) / via Zoom
Event Official Language: English
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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.
Venue: #435-437, Main Research Building / via Zoom
Event Official Language: English
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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
Event Official Language: English
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Lecture
NU-Q-iTHEMS-YITP Lecture: Applications of Quantum Computation in Quantum Field Theory
July 6 (Thu) - 7 (Fri) 2023
Masazumi Honda (Assistant Professor, Yukawa Institute for Theoretical Physics, Kyoto University)
This lecture aims to provide an introductory explanation of the application of quantum computation in numerical simulations of quantum field theory. We will begin by covering the fundamental aspects of quantum computation, followed by a discussion on its application to simulating spin systems. Subsequently, we will delve into introductory explanations of continuous field quantum theory and lattice field quantum theory, and discuss their simulation methods. Additionally, practical exercises utilizing IBM Qiskit for quantum simulations will be conducted. Important Notice for Participants: Please note that loaner laptops for the practical exercises will not be provided, so please bring your own laptops. Prior to the lecture, please ensure that you have set up your environment to use Jupyter Notebook, for example, by installing Anaconda. Organizers: Quantum Research Center (NU-Q), Niigata University / Yukawa Institute for Theoretical Physics (YITP), Kyoto University Co-organizer: RIKEN Interdisciplinary Theoretical and Mathematical Sciences Program (iTHEMS)
Venue: #A317, Building A, Faculty of Science, Niigata University / via Zoom
Event Official Language: Japanese
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