応用物理学輪講 I
6月20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
2025年6月20日(金) 16：50～18：50

Aグループ

座長
渡邉　楓花
指導
教員名
福谷　克之　教授
座長
陳　正力
指導
教員名
中村　泰信　教授
発表者名 太附　孝輔
指導教員名 森本　高裕　准教授
発表題目（英語） Microscopic theory of the inverse Faraday effect in a multiorbital model
要旨（英語） The inverse Faraday effect (IFE) is one of the magnetooptical effects where static magnetization is induced in materials by irradiation with circularly-polarized light. With the help of recently developed laser technology, this effect has been observed in various materials in the experiments such as pump-probe measurements and spin current detection techniques. The IFE has attracted keen attention for its potential applications in opto-spintronics, as it allows for the ultrafast control of magnetization in materials. In this study, we theoretically investigate the IFE in a multiorbital metallic system. We first show that the electric dipole moment of Wannier orbitals contributes to the orbital magnetic moment, which is not included in the conventional expression for the orbital magnetic moment in lattice systems. Furthermore, using both analytical and numerical approaches, we demonstrate that the orbital magnetic moment exhibits a significantly larger response compared to the spin magnetic moment, with all contributions to the orbital magnetic moment being comparable in magnitude. These findings highlight the essential role of orbital degrees of freedom in the IFE.
発表言語 日本語
発表者名 寺河　俊宏
指導教員名 Max Hirschberger 准教授
発表題目（英語） Inversion and Time-Reversal Symmetry Breaking at Interface of High-Tc Cuprate Superconductor
要旨（英語） Nonreciprocal response refers to a phenomenon in which a system exhibits different behavior depending on the direction of an applied stimulus, arising in the absence of inversion symmetry. When time-reversal symmetry is also broken, a specific form of nonreciprocal transport known as magnetochiral anisotropy can occur. This effect is particularly enhanced in superconductors, where transport properties are governed by low energy scales.

In this study, we fabricate heteroepitaxial thin films composed of the high-temperature cuprate superconductor La2-xSrxCuO4 (LSCO) and the strong spin–orbit-coupled oxide CaIrO3. The aim is to induce and investigate nonreciprocal phenomena, including the magnetochiral anisotropy, at the interface of this heterostructure. This presentation reports on our current progress toward synthesizing high-quality thin films suitable for these investigations.
発表言語 英語
発表者名 寺薗　隆之
指導教員名 小林　洋平　教授
発表題目（英語） Enhancement of Sensitivity for a Mid-Infrared Dispersive Spectroscopic System in the 8～12 µm Region for Breath Analysis
要旨（英語）  The mid-infrared (MIR) spectral range, often referred to as the "molecular fingerprint region," is crucial for various applications, including breath analysis and environmental monitoring, due to the presence of numerous characteristic molecular vibrational absorption lines. Breath analysis, in particular, demands real-time, high-resolution detection of multiple trace gases (~1 ppm) with a high signal-to-noise ratio (SNR).

 To address this need, we have developed a dispersive spectroscopic system covering two MIR bands (3–5 µm and 8–12 µm), which utilizes a Germanium-based extremely high-order diffraction grating (Ge-EGIG) and a Herriott cell [1, 2]. Previously, our 8–12 µm setup was limited by a relatively low SNR of approximately 130, achieved with an integration time of 600 ms (30 frames).

 In this work, we focused on enhancing the system's sensitivity. By improving our Ytterbium (Yb) amplifier and implementing an end-cap on the photonic crystal fiber (PCF) facet, we successfully increased the MIR light power from 100 µW to 1 mW. This enhancement resulted in a significant improvement of the SNR to 1000. This presentation will report on the upgraded, high-sensitivity experimental system and present the results from absorption spectroscopy measurements of sample gases.

References: [1] K. Taya, et al., Master's Thesis (2023). [2] Y. Ishizuka, et al., Master's Thesis (2022).
発表言語 日本語

Bグループ

座長
尹　建
指導
教員名
齊藤　英治　教授
座長
青柳　俊吾
指導
教員名
金澤　直也　准教授
発表者名 東條　開斗
指導教員名 沙川　貴大　教授
発表題目（英語） Optimizing optimal transport: role of final distributions in finite-time thermodynamics
要旨（英語） 　In thermodynamics, the second law is considered the most fundamental principle. However, equality is achieved only via a quasi-static limit, which is impractical for real-world applications. It is well established that the minimum entropy production which is necessary for transitions between fixed initial and final states in finite time and the protocol achieving it can be derived using optimal transport theory [1].
　When multiple final states can fulfill a desired objective, optimal transport allows the final state to be adjusted to further minimize thermodynamic costs. In contrast to previous studies that minimized costs for specific tasks like information erasure, measurement, and feedback in particular settings [2,3,4], our research introduces a unified framework for thermodynamic optimization in overdamped Langevin systems. This framework optimizes thermodynamic costs such as entropy production and work in finite time while ensuring that state-dependent quantities like expectation values of physical quantities or mutual information reach their desired targets. The optimization problem is formulated as a variational problem over transport maps. Consequently, our approach addresses various settings such as particle transport, fluctuation reduction processes, information erasure, measurement, and feedback.
　In this presentation, we will introduce the basic concepts of stochastic thermodynamics and then present results of our study.

[1] E. Aurell, K. Gawedzki, C. Meija-Monasterio, R. Mohayaee, and P. Muratore-Ginanneschi, Journal of Statistical Physics 147, 487 (2012).
[2] K. Proesmans, J. Ehrich, and J. Bechhoefer, Phys. Rev. Lett. 125, 100602 (2020).
[3] R. Nagase and T. Sagawa, Phys. Rev. Res. 6, 033239 (2024).
[4] R. Nagase and T. Sagawa, arxiv:2503.12802 (2025).
発表言語 日本語
発表者名 中島　将貴
指導教員名 古澤　明　教授
発表題目（英語） Non-Gaussian State Generation and Measurement with Pulse and Continuous Wave Light
要旨（英語） Light has the potential to realize quantum computers because it operates at room temperature and pressure and has a high carrier frequency. Especially, in the field of optical continuous quantum information processing, the generation of non-Gaussian state using picosecond pulsed light and broadband homodyne measurement using optical parametric amplifiers have been reported. While pulsed light has an advantage in non-Gaussian state generation, continuous wave light has one in high-speed measurement. Therefore, it is necessary to integrate them.
We aim to demonstrate the continuous wave light homodyne measurement of non-Gaussian states generated by a pulsed light . 
In this presentation, I will give an overview of quantum state generation and quantum state measurement. Finally, I will share the current progress.
発表言語 英語
発表者名 永山　裕一
指導教員名 木村　隆志　准教授
発表題目（英語） Development of soft X-ray reflection ptychography using a long-working-distance mirror optics
要旨（英語） Element-specific and magnetically sensitive soft X-ray microscopy is attracting interest for investigating material properties. Traditional transmission-type setups, however, require samples to be thin and highly transparent. In this work, we developed a reflection-type system where soft X-rays strike the sample near the critical angle, and the reflected signal is captured. We demonstrate high-resolution imaging using ptychographic phase retrieval, achieved with a long-working-distance optical setup at BL25SU, SPring-8.
発表言語 日本語
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