応用物理学輪講 I
11月17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
2023年11月17日（金）16：50～18：50

Aグループ

座長
河野　秀城
指導
教員名
小芦　雅斗　教授・藤井　啓祐　委嘱教授
座長
佐藤　真武
指導
教員名
平山　元昭　特任准教授
発表者名 白石　蒼馬
指導教員名 吉岡　孝高　准教授
発表題目（英語） Numerical simulation on laser cooling of positronium
要旨（英語） Laser cooling is a technique that slows atoms and molecules by radiation pressure, and allows precise measurements and control of quantum systems. One of the interesting systems to be cooled is positronium, which is a purely leptonic exotic atom. Cold positronium provides a strict testing ground for fundamental theories of physics, such as quantum electrodynamics.
In this study, we estimated the laser cooling effect on positronium by numerical simulation based on the Lindblad master equation and showed that chirp cooling, which is one of the methods of laser cooling, can reach a nearly recoil-limited temperature even though positronium has a short lifetime.
The simulation was able to reproduce an experimental result that demonstrated one-dimensional chirp cooling of positronium, which was cooled down to approximately 1 K.
発表言語 日本語
発表者名 鈴木　拓海
指導教員名 古澤　明　教授
発表題目（英語） All-optical quantum teleportation for ultrafast quantum computation
要旨（英語） An optical quantum computer is based on quantum teleportation.

As the frequency of light is several hundred THz, an optical quantum computer with a clock frequency of 1 THz is feasible in principle.
Conventional quantum teleportation has been limited to the order of 100 MHz by the bandwidth of photoelectric conversion and signal processing.

We therefore focused on all-optical quantum teleportation, which utilizes optical parametric amplifiers to make measurements and feedforward without electrical signals.

I will present two of our achievements toward all-optical quantum teleportation.
発表言語 英語
発表者名 先崎　俊亮
指導教員名 川﨑　雅司　教授
発表題目（英語） Topological Hall effect through proximity effect at pyrochlore hetero interface of magnetic insulator and non-magnetic metal
要旨（英語） Topological Hall effect is expected to emerge in magnetic metals with non-coplanar spin structure, in which the spin structure is topologically non-trivial in real space, and both experimental and theoretical research is being actively carried out.
The pyrochlore oxide Ho2Sn2O7, known as classical spin ice, exhibits a peculiar magnetism with a non-coplanar spin structure and is expected to exhibit a topological Hall effect originating from the scalar spin chirality. However, Ho2Sn2O7 is an insulating material and cannot be evaluated for its electrical and magnetotransport properties on its own.
In my study, a hetero-interface sample was prepared by depositing a paramagnetic metal pyrochlore-type oxide Pb2Ru2O6.5 as an electrical conducting layer on Ho2Sn2O7. I will talk mainly about the sample fabrication and expectation of my research about topological Hall effect.
発表言語 日本語

Bグループ

座長
小林　海翔
指導
教員名
求　幸年　教授
座長
小林　尚暉
指導
教員名
中島　多朗　准教授
発表者名 首藤　龍馬
指導教員名 長谷川　達生　教授
発表題目（英語） Manufacturing Crystalline Thin Film of Plastic/Ferroelectrics and Visualization of Polarization Domains
要旨（英語） Molecular ferroelectric crystals have attracted growing interest as potential alternatives to widely used ferroelectric perovskite oxides. Plastic/ferroelectric crystals are a new class of molecular ferroelectric crystals, which have a plastic crystal phase as a paraelectric phase which exhibits malleability at high temperatures and a ferroelectric phase at low temperatures. Plastic/ferroelectric crystals have several advantages such as multiaxial ferroelectricity due to the cubic crystal symmetry in the paraelectric phase and facile fabrication of thin film. In our research, we manufactured crystalline thin film of new plastic/ferroelectric crystals [MDABCO][PF6] by three solution processes: confined growth, drop-casting and blade-coating, and visualized polarization domains.
発表言語 日本語
発表者名 土田　真嗣
指導教員名 長谷川　達生　教授
発表題目（英語） Low-temperature device characteristics and origin of injection barrier in sharp switching organic transistors
要旨（英語） Organic thin film transistors (OTFTs) are promising for next-generation devices because of their features such as flexibility and solution-processability. Bottom-contact (BC) OTFTs, in which the electrodes exist under the organic semiconductor thin film, are particularly expected to be in practical use due to their structural advantages. However, BC-type OTFTs do not show high performance because they have large carrier injection barrier at the ternary interface where three different materials (electrode / organic semiconductor / insulator) are integrated. In this study, we investigated the injection barrier at the ternary interface from the low-temperature device characteristics in sharp switching OTFTs. By using sharp switching OTFTs with trap-free transport interfaces, transport and injection can be separated and we can focus only on the injection barrier. In this presentation, we will discuss the origin of the injection barrier based on the temperature dependence of mobility and the behavior of activation energy.
発表言語 日本語
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