応用物理学輪講 I
5月10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5月10日（金）　16：50～18：50（初回ガイダンスのため、16：45にＡグループのURLにアクセスしてください。）

Aグループ

座長
松永　響
指導
教員名
有田　亮太郎　教授
座長
曾　可嘉
指導
教員名
芦原　聡　教授
発表者名 肥田　宏太郎
指導教員名 中村　泰信　教授
発表題目（英語） Flux-trapping fluxonium
要旨（英語） Among many types of superconducting qubits, a fluxonium qubit is a promising candidate for the physical realization of a superconducting quantum computer thanks to its long coherence time and large anharmonicity at its optimal operation point, called a sweet spot.

The main obstacle to integration of fluxoniums is the need for precise external magnetic flux control. Introducing bias lines for each fluxonium is necessary to realize its sweet spot, but it results in complex wiring overhead and undesirable crosstalks.

To solve this issue, we focused on fluxoid quantization. In this presentation, I will introduce a flux-trapping fluxonium, which can realize its sweet spot without external flux bias by leveraging fluxoid quantization inside its superconducting ring.
発表言語 英語
発表者名 池原　至恩
指導教員名 武田　俊太郎　准教授
発表題目（英語） Demonstration of continuous-variable quantum machine learning using optical circuits
要旨（英語） Among various quantum machine learning (QML) algorithms, the quantum kernel method has especially attracted attention due to its compatibility with noisy intermediate-scale quantum devices and its potential to achieve quantum advantage. This method performs classification and regression by nonlinearly mapping data into quantum states in a higher dimensional Hilbert space. Thus far, the quantum kernel method has been implemented only on qubit-based systems, but continuous-variable (CV) systems can potentially offer superior computational power by utilizing its infinite-dimensional Hilbert space. Here, we demonstrate the implementation of the classification task with the CV quantum kernel method on a programmable photonic quantum processor. We experimentally prove that the CV quantum kernel method successfully classifies several datasets robustly even under the experimental imperfections, with high accuracies comparable to the classical kernel. In this talk, I'll report on the implementation and demonstration of the CV QML on a programmable photonic quantum processor.
発表言語 英語
発表者名 ZAINUDIN Redza
指導教員名 中村　泰信　教授
発表題目（英語） Introduction to fluxonium superconducting qubits.
要旨（英語） Fluxonium qubits have been gaining popularity amongst superconducting quantum computing circles. This can be mainly attributed to their long coherence times compared to other qubit types, such as transmons.
This presentation will introduce the current types of qubits, working from basic oscillators up to fluxonium qubits. The concepts and implementations of qubit control and readout will also be described. Lastly, a recent paper outlining a novel method for qubit readout will be discussed.
発表言語 英語

Bグループ

座長
陈　杨菘
指導
教員名
為ヶ井　強　准教授
座長
于　澄
指導
教員名
為ヶ井　強　准教授
発表者名 井上　裕貴
指導教員名 関　真一郎　准教授
発表題目（英語） Anomalous Hall effect in time-reversal symmetry-broken antiferromagnet
要旨（英語） Conventionally, magnetic information is stored in ferromagnets owing to their time-reversal symmetry breaking. On the other hand, general antiferromagnets are not believed that they can work as information carrier because of their time-reversal symmetry. However, according to recent studies, it was found that some antiferromagnets break time-reversal symmetry and can store magnetic information [1]. Moreover, under such antiferromagnets, anomalous responses without net magnetization such as anomalous Hall effect can be realized, which are usually induced by net magnetization and so typical in ferromagnets.
In this presentation, I will explain time-reversal symmetry-broken antiferromagnets and talk about experimental results of candidate materials.

[1] S. Nakatsuji et al., Nature 527, 212 (2015)
発表言語 日本語
発表者名 伊豆　駿佑
指導教員名 福谷　克之　教授
発表題目（英語） Hydrogen adsorption and restructure of Ag(111)-Bi surface
要旨（英語） Ag(111)-Bi surface is known as surface which has giant Rashba splitting. In the Rashba system, the inverse Edelstein effect, in which an electric current is generated by injecting a spin current, is expected. In order to inject a spin current into Ag(111)-Bi surface, a beam of spin-polarized hydrogen atoms is injected into the surface. Then, we must examine the characteristic of hydrogen adsorption. During this experiment, we found that Bi atoms vanish from surface by hydrogen adsorption. In this lecture, I introduce experimental result and consideration of Bi atoms’ vanishment.
発表言語 日本語
発表者名 石原　由貴
指導教員名 Max　Hirschberger　准教授
発表題目（英語） Investigating magnetic structure of two materials which causes topological phenomena : Nd3Ru4Al12 and GdAlSi
要旨（英語） Quantum materials demonstrate characteristic phenomena like Nernst effect, due to its topological spin structure, because the spin scaler chirality has non-zero value. As the target material that realizes topological phenomena, we are investigating the magnetic structure of two materials: Nd3 Ru4Al12 and GdAlSi.

Nd3Ru4Al12 has the structure called Kagomé lattice. As for Nd3Ru4Al12, a previous paper suggested that ferromagnetic state with different magnetic moment site to site is realized in the material. However, our previous works have concluded this magnetic model is not likely realized, rather we find a much more interesting, noncollinear magnetic structure by polarized neutron scattering measurement in 5G-PONTA.

GdAlSi, where a large electronic anisotropy occurs due to the magnetic order, has helical spin structure. By analyzing the dataset with refinement considering absorption correction due to Gd3+, I tried determining details of magnetic structure of the material.
発表言語 英語
応用物理学輪講 I一覧ページへ戻る