This is a seminar jointly organized by the three groups working on quantum physics and technology at Department of Physics, Kindai University, namely Condensed-Matter Theory (CMT), Quantum Control (QC), and QMB Laboratories.
Scheduled talks
Fiscal year 2025
Time and date: 10:45-, April 9, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Furuchi, Rito (QMB)
Title: Theoretical study of frustrated quantum spin systems with exact diagonalization
Abstract: We study frustrated antiferromagnets using the exact diagonalization method. The type of frustration addressed in this research occurs in localized spin systems, such as those represented in half-filled Mott insulators. This frustration occurs when antiferromagnetic interactions construct networks with odd-gons as local structures, causing a variety of exotic phenomena. Extensive studies have been reported on the triangular lattice[1] and the kagome lattice[2] as typical frustrated systems. The Heisenberg model describes such localized spin systems.
Computational approaches such as the quantum Monte Carlo (QMC) method and the density matrix renormalization group (DMRG) method are effective methods to study the Heisenberg model. However, the QMC method suffers from the negative sign problem in frustrated systems, while DMRG faces challenges in interpreting results for systems with two or more spatial dimensions. To avoid these problems, we employ the exact diagonalization method, which, although restricted to systems with a small number of spins, can calculate frustrated system.
Time and date: 10:45-, April 16, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Yoshida, Takaharu (Tokyo University of Science)
Title: Proposal for experimental realization of quantum spin chains with quasiperiodic
interaction using Rydberg atoms
Abstract: Investigating the localization properties of interacting disordered systems plays a crucial role in understanding the fundamental origins of both the emergence and the breakdown of statistical mechanics in closed quantum systems. However, simulating such systems on classical computers is challenging due to their complexity. On the other hand, recent advances in experimental technology have made it possible to realize closed quantum systems with high controllability. In particular, Rydberg atoms [1] are an emerging platform for quantum simulation, as they offer the advantage of individual control over the spatial positions of atoms and the ability to tune their interactions.
In this talk, I will talk about my recent work proposing an experimental method to realize S=1/2 and S=1 quantum spin models with quasiperiodic interactions using Rydberg atoms [2]. I will also present numerical results for these models, confirming that they exhibit a many-body critical (MBC) regime [3], a newly reported localization phenomenon distinct from both ergodic and many-body localized phases.
[1] A. Browaeys, D. Barredo, and T. Lahaye, J. Phys. B At. Mol. Opt. Phys. 49, 152001 (2016).
[2] T. Yoshida, M. Kunimi, and T. Nikuni, arXiv:2409.08497 (2024).
[3] Y. Wang, C. Cheng, X.-J. Liu, and D. Yu, Phys. Rev. Lett. 126, 080602 (2021).
Time and date: 10:45-, April 23, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Pelayo, Jose Carlos (QMB)
Title: Ultracold Atoms: Applications in Metrology and Fundamental Properties of Quantum Droplets
Abstract: In recent decades, cold atoms have become indispensable tools for exploring fundamental physics and advancing quantum technologies. In this talk, I will delve into this broad landscape by presenting two topics from my PhD research, focusing on quantum metrology and quantum mixtures. In the first part of the talk, I will demonstrate how a Floquet-engineered bosonic system in a one-dimensional lattice can serve as a platform for quantum metrology. In the second part, I will turn to quantum mixtures involving a relatively new phase of matter known as quantum droplets, where I investigate the role of dimensionality in the formation of droplets.
Time and date: 10:45-, April 30, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Tanaka, Airi (CMT)
Title: Dynamics of superfluid wake behind a plate-shaped obstacle
Abstract: In fluid mechanics, study of a flow that occurs behind an obstacle (wake) when a fluid passes through the obstacle is an important subject for understanding the behavior of fluids, and is therefore a subject of very active research. However, there has been less research on wakes in superfluids compared to classical fluids. The shapes of obstacles used in studies of the wake of superfluids are almost always assumed to be cylindrical, and the state of the wake around a plate-shaped obstacle has not yet been explored. In this study, we numerically investigate the fluid flow behind a plate-shaped obstacle by using the Gross–Pitaevskii equation, a model equation for the macroscopic wave function of a Bose-Einstein condensate. As a result, we are able to classify the wake state by changing the size and speed of the plate-shaped obstacle.
Time and date: 10:45-, May 14, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Yabuuchi, Yoshihiro (QMB)
Title: TBA
Abstract: TBA
Time and date: 10:45-, May 21, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Kuji, Hiroki (Tokyo University of Science)
Title: TBA
Abstract: TBA
Time and date: 10:45-, May 28, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Sidharth Rammohan (QMB)
Title: TBA
Abstract: TBA
Time and date: 10:45-, June 4, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Kanada, Kouhei (Quantum Field Theory and Elementary Particle Theory Group)
Title: TBA
Abstract: TBA
Time and date: 10:45-, June 11, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Kaji, Yuuto (Quantum Field Theory and Elementary Particle Theory Group)
Title: TBA
Abstract: TBA
Time and date: 10:45-, June 18, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Takegami, Hibiki (Kyoto University)
Title: TBA
Abstract: TBA
Time and date: 10:45-, June 25, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Ueda, Kenta (QMB)
Title: TBA
Abstract: TBA
Time and date: 9:00-, July 2, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker 1: Tabuchi, Youta (Quantum Field Theory and Elementary Particle Theory Group)
Title: TBA
Abstract: TBA
Speaker 2: Aioi, Erena (Solid State Physics Group)
Title: TBA
Abstract: TBA
Time and date: 10:45-, July 9, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: Yuri, Takumi (Osaka Univ.)
Title: TBA
Abstract: TBA
Time and date: 10:45-, July 16, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: TBA
Title: TBA
Abstract: TBA
Time and date: 10:45-, July 23, 2025
Room: Simulation and Experiment Room, 3rd Floor, 31 East Bldg. + Webcast via Zoom
Speaker: TBA
Title: TBA
Abstract: TBA