STAMP Seminar
12 events

Seminar
Potential Toolkit to Attack Nonperturbative Aspects of QFT －Resurgence and related topics－
September 7 (Mon)  25 (Fri), 2020
Aleksey Cherman (University of Minnesota, USA)
Gerald Dunne (University of Connecticut, USA)
Mithat Unsal (North Carolina State University, USA)
Toshiaki Fujimori (Keio University)
Yasuyuki Hatsuda (Rikkyo University)
Masazumi Honda (Assistant Professor, Yukawa Institute for Theoretical Physics, Kyoto University)
Okuto Morikawa (Ph.D. Student, Kyushu University)
Naohisa Sueishi (Nagoya University)
Masahito Yamazaki (Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), The University of Tokyo)Recently, there have been significant developments in theoretical techniques/frameworks to tackle nonperturbative aspects of quantum field theory (QFT) such as the resurgence theory, the Lefschetz thimble method, ’t Hooft anomaly matching, and novel lattice setups. Such developments are still growing very rapidly and making fruitful connections not only among physicists involved in fields with broad energy scales but also with mathematicians. These developments would enable us to unveil rich and exciting physics of QFT in the nonperturbative regime. It is of primary importance to hold a workshop for researchers in various fields related to the topics to get together and overview/share the recent progresses, to discuss future directions, and to seek for possible new collaborations bridging various fields of physics/mathematics. For more information, please see on the related link.
Venue: YITP (Kyoto University), Zoom, and Mozilla hubs
Event Official Language: English

Seminar
Introduction to quantum manybody system
September 5 (Thu)  6 (Fri), 2019
Hosho Katsura (Associate Professor, Department of Physics, Graduate School of Science, The University of Tokyo)
Venue: #535537, Main Research Building / #435437, Main Research Building
Event Official Language: Japanese

Seminar
Large scale dynamics of integrable systems
July 12 (Fri) at 16:00  17:00, 2019
Takato Yoshimura (King's college London, UK)
Hydrodynamics has been a universal tool to study the large scale (longwavelength) dynamics of interacting manybody systems. It had not been, however, applied to integrable systems until 2016 when two papers, one of which is ours [Physical Review X 6 (4), 041065, (2016)], provided a first legitimate hydrodynamic theory of integrable systems that incorporates the anomalous number of conserved quantities in those systems. The key idea of the theory rests upon the use of thermodynamic Bethe ansatz that allows us to express the essential ingredients in hydrodynamics, densities and currents average of conserved charges, in terms of the quasiparticle basis. In this talk I will review this new hydrodynamic theory, coined generalized hydrodynamics (GHD). I will first introduce the basics of GHD, highlighting the difference with the conventional hydrodynamics (i.e. hydrodynamics for nonintegrable systems). I will then present some recent developments in the theory, such as the exact computation of the Drude weight and hydrodynamic correlation functions.
Venue: Building 14 #213, Yagami campus, Keio University
Event Official Language: English

Seminar
Spintronics in NonInertial Frames
November 15 (Thu) at 13:00  18:00, 2018
Mamoru Matsuo (University of Chinese Academy of Sciences, China)
Venue: Seminar Room #160
Event Official Language: Japanese

Seminar
NonHermitian phase transition from a polariton BoseEinstein condensate to a photon laser
September 28 (Fri) at 13:30  17:00, 2018
Ryo Hanai (Osaka University)
Venue: Seminar Room #160
Event Official Language: Japanese

Introduction to topological band structure
July 6 (Fri) at 10:30  17:30, 2018
Tomoki Ozawa (Senior Research Scientist, iTHEMS)
In this seminar, I give an introduction to topological band structures. Topological band structure is the fundamental idea to understand phenomena such as the quantum Hall effect, topological insulators, and topological superconductors. Although originally found in fermionic electron systems, topological band structure is essentially a singleparticle property, and thus the same phenomenon can arise also in bosonic systems. In fact, topological band structure does not even need quantum mechanics; topological band structure can arise in classical waves inside a periodic medium, such as electromagnetic waves or classical mechanical waves. In this seminar, I first give a brief introduction to key concepts in topological band structures, such as Berry curvature, Chern number, bulkedge correspondence, and tenfold way classification of topological insulators. I then explain how topological band structure can arise in classical systems, giving a brief introduction to the field of topological photonics and topological mechanics.
Venue: Seminar Room #160
Event Official Language: Japanese

Seminar
Introduction to spinboson model
June 22 (Fri) at 10:30  17:30, 2018
Takeo Kato (The Institute for Solid State Physics (ISSP), The University of Tokyo)
10:3012:30 Introduction to spinboson model @DR3 (14th Building 213) 14:0015:30 Kondo effect @DR7 (14th Building 217) 16:0017:30 Detail of NIBA formalism @DR7 (14th Building 217)
Venue: Yagami Campus, Keio University
Event Official Language: Japanese

Seminar
1form LiebSchultzMattis theorem and anomaly matching in quantum dimer model
June 8 (Fri) at 13:30  17:00, 2018
Yuta Kikuchi (RBRC Researcher, Theory Group, RIKEN BNL Research Center, RIKEN Nishina Center for AcceleratorBased Science (RNC))
The LiebSchultzMattis theorem dictates that a trivial symmetric insulator in lattice models is prohibited if lattice translation symmetry and U(1) charge conservation are both preserved. In this talk, we discuss the generalization of the LiebSchultzMattis theorem to systems with higherform symmetries, which act on extended objects of dimension n > 0. The prototypical lattice system with higherform symmetry is the pure abelian lattice gauge theory whose action consists only of the field strength. We first construct the higherform generalization of the LiebSchultzMattis theorem with a proof. We then apply it to the U(1) lattice gauge theory description of the quantum dimer model on bipartite lattices. Finally, using the continuum field theory description in the vicinity of the RokhsarKivelson point of the quantum dimer model, we diagnose and compute the mixed ’t Hooft anomaly corresponding to the higherform LiebSchultzMattis theorem.
Venue: SUURICOOL (Kyoto)
Event Official Language: Japanese

Seminar
AbelianHiggs dualities in quantum defectmediated melting phase transitions
April 27 (Fri) at 14:30  17:30, 2018
Aron Beekman (Keio University)
In the study of zerotemperature quantum phase transitions, instead of looking how symmetry is broken, it is often useful to see how symmetry can be restored by the condensation of topological defects. Through a duality mapping, NambuGoldstone modes are represented as gauge bosons, mediating longrange interactions between topological defects. When the latter condense, those bosons get as mass via the AndersonHiggs mechanism, which signals the loss of rigidity and the restoration of symmetry. I will first review the beststudied case: the 2+1D superfluidinsulator transitions where the defects are U(1) vortices. Consecutively several extensions are discussed: going to 3+1D where the defects are not point particles but strings, and quantum elasticity, which studies breaking of spatial translations and rotations.
Venue: Seminar Room #160
Event Official Language: English

Resurgence Theory for NonPerturbative Quantum Analysis
March 28 (Wed) at 13:00  15:00, 2018
Tatsuhiro Misumi (Visiting Scientist, iTHEMS / Lecturer, Akita University)
Venue: Seminar Room #160
Event Official Language: English

Seminar
Introduction to exact WKB analysis
March 27 (Tue) at 10:00  12:00, 2018
Kohei Iwaki (Nagoya University)
Venue: Seminar Room #160
Event Official Language: English

Seminar
Anomaly matching for spin chains
March 19 (Mon) at 14:00  16:00, 2018
Yuya Tanizaki (Special Postdoctoral Researcher, Theory Group, RIKEN Nishina Center for AcceleratorBased Science (RNC))
Venue: Seminar Room #160
Event Official Language: English
12 events