応用物理学輪講 I
11月15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11月15日（金）16：50～18：50

Aグループ

座長
鈴木　大吾
指導
教員名
石坂　香子　教授
座長
鈴木　拓海
指導
教員名
古澤　明　教授
発表者名 竹中　涼
指導教員名 高橋　陽太郎　准教授
発表題目（英語） Magnetically induced second harmonic generation in cycloidal Weyl semimetal GdAlSi
要旨（英語） Weyl semimetals show various physical response derives from the Berry curvature and symmetry breaking. Especially in magnetic Weyl semimetals, the unique functionalities allowed by both P and T breaking are expected to provide a good platform for the search for novel functionalities. In the case of second harmonic generation (SHG), Giant magnetically induced nonlinear susceptibility and unique optical functionality such as nonlinear optical diode effect has been reported in ferromagnetic Weyl semimetals PrAlGe.
In this study, we have extended the search for magnetically-induced SHGs in magnetic Weyl semimetals from ferromagnetic to cycloidal Weyl semimetals.
発表言語 日本語
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） Theoretical study of the inverse Faraday effect in a multiorbital model
要旨（英語） The inverse Faraday effect is a phenomenon where magnetization is induced when circularly polarized light is irradiated onto a material. This effect has attracted significant attention as it offers a promising way to achieve rapid control of magnetization.
Microscopic theories of the inverse Faraday effect include perturbation theory in Dirac electron systems [1,2] and analyses using Floquet theory in Rashba electron systems [3,4]. However, these analyses have neglected the contributions from electric dipole transitions, and the interplay between these contributions and spin-orbit coupling remains insufficiently elucidated.
In this presentation, we will explain our formalism of the light-matter coupling in an *s*-*p* electron system and present a perturbation analysis between *s*-*p* orbital combined with Floquet theory. Furthermore, we will demonstrate that the inverse Faraday effect can be induced through hybridization between *s*-*p* orbitals, leading to an enhancement near the resonance frequency.
発表言語 日本語
発表者名 滝之入　敬汰
指導教員名 長谷川　幸雄　教授
発表題目（英語） The microscopic study of nonreciprocal conduction using scanning tunneling microscopy
要旨（英語） Scanning tunneling microscopy/potentiometry (STM/P), which allows us to get surface images with atomic-scale spatial resolution and electrochemical potential images with microvolt resolution, is a powerful tool to study surface conductivity in nanoscale. In our laboratory, we have performed STP measurements at low temperature and under magnetic fields to demonstrate unique transport properties in the specific conditions. One of the results shows that atomic step structure of Pb on Si (111) acts as a electrical resistance and suggests nonreciprocal conduction across steps. Now we’re working on improving equipment and substrates for performing four-terminal I-V measurements in STM.

In this presentation, I will discuss the microscopic study of nonreciprocal conduction using STM/STP. I will also introduce some theses about nonreciprocal charge transport, especially superconducting diode effect.
発表言語 日本語

Bグループ

座長
先崎　俊亮
指導
教員名
川﨑　雅司　教授
座長
土田　真嗣
指導
教員名
長谷川　達生　教授
発表者名 寺河　俊宏
指導教員名 Max　Hirschberger　准教授
発表題目（英語） Nernst effect enhanced by Fermi surface nesting in band touching semimetal GdPtBi
要旨（英語）     Fermi surface nesting in conduction electrons can give rise to a variety of quantum phases, such as charge density waves and spin density waves. One effective method to investigate the electronic structure near the Fermi surface is by studying the Nernst effect, which is influenced by the filling dependence of both the carrier density and the relaxation time. Recently, the enhancement of the latter, closely tied to electron correlations and Fermi surface nesting, has garnered attention.

    In this presentation, I will discuss our study of the Nernst effect driven by electron correlations in the band touching semimetal GdPtBi. Using a k⋅p model combined with ab initio calculations, we suggest that Fermi surface nesting instability could enhance these correlations.
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） Construction of a precise molecular spectroscopy system in the 10 µm mid-infrared region
要旨（英語） Mid-infrared spectroscopy has been proposed for applications such as air pollution monitoring, fuel analysis, and breath analysis for real-time detection of trace gases. In developed countries like Japan, where the population is rapidly aging, breath analysis is particularly significant as a non-invasive diagnostic method. It is less burdensome for patients, allows quicker diagnosis, and contributes to early disease detection. In this presentation, I will discuss the progress and future plans for developing a precise molecular spectroscopy system utilizing 10 µm mid-infrared light source.
発表言語 日本語
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） Optimization of finite-time work extraction and its application to information-to-work conversion
要旨（英語） Maximizing extractable work from a given system is crucial in designing thermodynamic machines, such as heat engines and biomolecular systems. While the theoretical upper bound of extractable work is quantified by the second law of thermodynamics, achieving this bound requires a quasi-static process, rendering it unattainable in finite-time operations. Thus, maximizing extractable work in finite time is a fundamental challenge. Recent studies have refined the second law by utilizing optimal transport theory, quantifying the maximal amount of extractable work within finite time for fixed initial and final states. However, the choice of final state can be further optimized to maximize extractable work, making it unnatural to fix the final state when aiming to maximize extractable work. In particular, for two coupled systems involving information processing, extractable work is enhanced beyond conventional second law utilizing correlations between the systems. Consequently, the methods for maximizing work extraction utilizing correlations from a given initial state through finite-time operations have not yet been well established.

In this study, we derive a method to maximize work extraction in finite-time processes by employing optimal transport theory and variational methods. Our general results are applicable to non-Gaussian processes,
while for Gaussian processes, we exploit their specific properties to derive an analytical expression of the extractable work. We demonstrate our framework by considering the setup of Maxwell’s demon, which performs feedback based on measured information of the system. Furthermore, we examine its information- thermodynamic efficiency and discuss its relation to the thermodynamic operational characterization of correlation in finite-time processes.
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） All-Optical Universal Squeezer 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 all-optical homodyne measurement using optical parametric amplifiers have been reported. However, while pulsed light is used for quantum state generation, continuous wave light is used for measurement-based quantum computation. Therefore, it is necessary to integrate them.
We aim to demonstrate an all-optical universal squeezer of continuous wave light with a non-Gaussian state generated by a pulsed light source as an input state.
In this presentation, I will give an overview of quantum state generation, quantum state processing, and all-optical manipulation. Finally, I will share the current progress.
発表言語 英語
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