応用物理学輪講 I
10月11日
[注意事項]
発表の10日前までに　office[at]ap.t.u-tokyo.ac.jp　宛てに「氏名」「指導教員」「発表題目（英語）」「要旨（英語）」「発表言語（英語または日本語）」を送付して下さい。
発表日
2024年10月11日（金）16：50～18：50

Aグループ

座長
小口　尚志
指導
教員名
井手上　敏也　准教授
発表者名 秋山　由洸
指導教員名 小林　洋平　教授
発表題目（英語） Development of Kerr-lens mode-locked Tm:YAG laser
要旨（英語） Ultrashort pulse lasers, known for their high peak intensities, are indispensable in both industrial and medical applications. Among the various generation methods, Kerr-lens mode-locking is notable for producing pulses with exceptionally short durations. Tm solid-state lasers, oscillating at a wavelength of 2 µm, have significant potential in fields such as polymer processing due to their unique characteristics. Kerr-lens mode-locking has been reported in Tm:YLF, Tm:Sc2O3, and other materials. However, achieving Kerr-lens mode-locking in Tm:YAG, a commonly used as gain medium, remains an ongoing challenge. This presentation will provide an overview of Kerr-lens mode-locking and discuss experimental approaches to its successful implementation in Tm:YAG systems, highlighting potential advancements for high-power laser applications.
発表言語 日本語
発表者名 浅井　僚眞
指導教員名 有田　亮太郎　教授
発表題目（英語） Structural Optimization of Nickelate Superconductors at Finite Temperatures
要旨（英語） La3Ni2O7 is a high-temperature superconductor that exhibits a transition temperature of 80 K at a high pressure of 14 GPa and has been the focus of much recent research. Since the emergence of superconductivity in La3Ni2O7 is accompanied by a structural phase transition, studying its dependence on temperature and pressure is important for understanding the underlying physics of superconductivity in La3Ni2O7 and related nickelate superconductors. In this talk, I will present our work on the structural optimization of RE3Ni2O7 (RE=La,Ce,...) based on Density Functional Theory at zero Temperature. Then I will discuss self-consistent phonon (SCP)
theory methods for finite temperature optimization.
発表言語 日本語
発表者名 新井　敦郎
指導教員名 求　幸年　教授
発表題目（英語） Self-learning Monte Carlo method
要旨（英語） Markov chain Monte Carlo is an unbiased numerical method for studying physical systems. A significant problem is that there exist correlations between configurations in the chain, especially around critical points, which leads to the drastic increase in the computational cost. For some models, Global update algorithms have been proposed to reduce the cost (e.g. Swendsen-Wang, Wolff). For most of the general models, however, any efficient global updating procedure is known.


In this presentation, based on [1], I will introduce the Self-learning Monte Carlo method, in which an effective model is first trained from the training data generated in trial simulation and then utilizing this model for update proposal. Self-learning Monte Carlo method is applied to a spin model at the phase transition point, achieving a 10-20 times speed up.


[1] J. Liu et al., Physical Review B 95, 041101(R) (2017)
発表言語 日本語

Bグループ

座長
葛西　章也
指導
教員名
求　幸年　教授
発表者名 池上　草玄
指導教員名 求　幸年　教授
発表題目（英語） Disorder and local topology on Chern Insulators
要旨（英語） A Chern Insulator (CI) is a two dimensional, topologically nontrivial insulator with broken time-reversal symmetry. Its topology is characterized by the Chern number, which corresponds to the number of chiral edge modes. These edge modes are topologically protected and robust against disorder. To study this robustness, previous research has employed so-called Anderson disorder, reporting that CIs transition to a trivial phase in the strong disorder limit. In contrast, we consider two periodic systems and connect them through selective random defects and investigate how the topological character of the electronic systems is connected. Since the wavenumber space is not well-defined in disordered systems, we employed crosshair marker to investigate the topology of electronic states. As a result, we found three patterns: (1) smooth connection between CIs, (2) a metal-to-CI transition, and (3) Selective defect induced topological transition. Our study clarifies the nontrivial connection of topology between two electronic systems.
発表言語 日本語
発表者名 池田　理玖
指導教員名 吉岡　孝高　准教授
発表題目（英語） Buffer gas cooling of carbon atoms
要旨（英語） Cooling techniques of atomic gases such as laser cooling have been applied to various atomic species, leading to diverse applications in quantum science. Buffer gas cooling is a cooling technique utilizing elastic collisions with cold, inert gas atoms. Since this cooling mechanism does not rely on the internal structure of the species to be cooled, buffer gas cooling can be applicable to nearly any atomic or molecular species.

In this presentation, we will introduce the basic concept, application and some technical aspects on buffer gas cooling. Finally, the current research progress made by our group will be presented, including the first application of buffer gas cooling to carbon atoms and the construction of a specialized light source for future spectroscopic measurements.
発表言語 日本語
発表者名 石井　智博
指導教員名 井手上　敏也　准教授
発表題目（英語） Exploring Microwave Responses in Atomically thin van der Waals materials
要旨（英語） Van der Waals materials can be easily fabricated into monolayer thin films through exfoliation. This characteristic allows for the arbitrary design of heterostructures, including twist degrees of freedom, which enable the control of physical properties. Previous measurements have focused on electronic transport and optical properties of 2D materials. In this study, I explored new probes of 2D materials using the microwave technics to measure the properties that cannot be accessed by DC transport and optics. 2D magnets and 2D superconductors are mainly studied.
発表言語 日本語
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