分数Chern绝缘体、高场超导磁体、拓扑绝缘体中的量子输运、氮化镓、超导量子器件 | 本周直播物理讲座

报告人：徐庆金，中国科学院高能物理研究所

时间：8月14日（周五）14:00

单位：中科院物理所

参加方式：讲座以线上形式进行，采用“腾讯会议”软件

会议ID：625 468 898

会议密码：0814

直播链接： 

https://meeting.tencent.com/l/QfWDYcDh4IgO

摘要：

粒子加速器是超导磁体技术最重要的应用领域之一：磁体场强的提高，将直接推动加速器能量的提高及规模与造价的降低。从20世纪70年代起的四十余年，国际上若干粒子加速器的建设，极大地推动了应用超导技术的发展及产业化：世界上第一个超导加速器：美国费米实验室的Tevatron加速器的建设，建立了超导线缆及磁体大规模制备的基础设施及商业化供应，开创了超导行业的发展，将超导核磁共振谱仪(MRI)在世界各地的医院中普及，极大地提高了人类的健康水平。国内外目前和未来拟建设的高能量加速器，如欧洲核子研究中心（CERN）提议建设的环形对撞机(FCC),以及我国科学家于2012年提出的超级质子对撞机(SPPC)，均基于高场超导磁体技术，且磁体的性能及成本，直接决定着项目的指标、造价甚至可行性。本报告将对粒子加速器中高场超导磁体技术的特点、挑战，及其对整个超导技术发展的巨大推动作用，做简要的介绍。

报告人简介：

徐庆金，中国科学院高能物理研究所研究员，高场超导磁体技术团队负责人，HL-LHC(大型强子对撞机高亮度升级) CCT国际合作项目负责人。2008至2014年于日本高能加速器研究机构(KEK)及欧洲核子研究中心(CERN)开展先进超导磁体技术研究，2014年入选中科院“引进国外杰出人才”。带领团队研制出中国第一个10T级高场超导二极磁体；与国内相关团队合作，国际上首次完成基于铁基超导材料的超导线圈研制及高场下性能验证；带领中国团队承担HL-LHC国际合作项目中新型CCT超导磁体的研制。

报告人：Dr. Di Xiao, Purdue University

时间：8月11日（周二）10:00

单位：中科院物理所

参加方式：讲座以线上形式进行，采用“腾讯会议”软件

会议ID：465 241 945    

会议密码：0811

直播链接： 

https://meeting.tencent.com/l/NAtNM1ZKSizH

摘要：

Topological insulators (TIs) are materials that conduct only via its topologically protected states on the boundary. Precise theoretical predictions, along with well-controlled material growths and characterizations, have led to the discovery of a series of topological insulators, such as the HgTe quantum well and Bi2Se3 family. In this talk, I will introduce the growth, characterization, and fabrication techniques of both 3D and 2D TIs, and discuss the exotic phenomena in transport studies. By constructing a magnetically doped 3D TI sandwich heterostructure, such that the top and bottom magnetic layers have distinct coercive fields, both the quantum anomalous Hall effect and the axion insulator state can be observed, when the magnetization alignment of the top and bottom layers is parallel and antiparallel, respectively. Another interesting result comes from a 2D TI system made of more conventional III-V semiconductor material, type-II InAs/GaSb quantum wells. By tuning relevant parameters, such as front/back gate voltages and thicknesses of the channel layers, one is able to enter a new insulating regime, with seemingly controversial high-density states, which can be explained by the effect of the attractive Coulomb interaction.

报告人简介：

Dr. Di Xiao is a postdoc associate in Prof. Michael Manfra’s group at Station Q Purdue and Department of Physics and Astronomy, Purdue University. He received his doctoral degree from Pennsylvania State University in 2019 under the supervision of Prof. Nitin Samarth. His current research interest is focused on the growth and fabrication of planar III-V semiconductor and superconductor materials, searching for the elusive Majorana fermions.

报告人：Dr. Bo Xiang, Materials Science and Engineering Program, University of California, San Diego

时间：8月13日（周四）10:00

单位：中科院物理所

参加方式：讲座以线上形式进行，采用“腾讯会议”软件

会议ID：111 312 330   

会议密码：0813

直播链接：

https://meeting.tencent.com/l/XqHDTuaTTyty

摘要：

Selective vibrational energy transfer between molecules in the liquid phase, a difficult process hampered by weak intermolecular forces, is achieved through polaritons formed by strong coupling between cavity photon modes and donor and acceptor molecules. Using pump-probe and two-dimensional infrared spectroscopy, we found that the excitation of the upper polariton, which is composed mostly of donors, can efficiently relax to the acceptors within ~5 picoseconds. The energy-transfer efficiency can be further enhanced by increasing the cavity lifetime, suggesting that the energy transfer is a polaritonic process. This vibrational energy-transfer pathway opens doors for applications in remote chemistry, sensing mechanisms, and vibrational polariton condensation.

报告人简介：

Dr. Bo Xiang is born in Zhejiang province in 1991. He obtained his Bachelor’s degree in Zhejiang university, majoring in materials science and engineering. After undergrad, he went to University of California, San Diego for his PhD career under the supervision of Prof. Wei Xiong. During his PhD study, he specialized in nonlinear spectroscopy, especially two-dimensional infrared spectroscopy. With the help of the spectroscopy tools, his research mainly focuses on polariton-assisted chemical reactions, quantum information transportation via vibrational strong coupling, and designing novel molecular vibrational polariton systems. He is also one of the pioneers who applied multi-dimensional spectroscopy in studying strong light-matter coupling in molecular vibrational regime.

报告人：Professor Lin Tian，School of Natural Sciences, University of California, Merced, USA

时间：8月11日（周二）10:00

单位：Frontiers of Physics编辑部，高教社自然科技期刊中心

参会方式：蔻享直播

直播链接：https://www.koushare.com/live/liveroom?islive=0&lid=334&roomid=038932

摘要：

The state-of-the-art of superconducting quantum devices enables the development of noisy intermediate-scale quantum systems with 50-100 qubits. Quantum simulators, a special purpose quantum computer, can possibly be implemented with such devices to solve problems that cannot be solved with classical computers in the near future. In this lecture, I will first give an overview of recent progresses in superconducting quantum simulation of many-body problems. Then I will discuss key issues in the practical implementation of superconducting quantum simulators. I will also present our recent works on these questions.

报告人简介：

Lin Tian received her Ph.D. in physics in 2002 from the Massachusetts Institute of Technology. After holding research positions at the University of Innsbruck, NIST at Gaithersburg, and Stanford University, she joined the School of Natural Sciences at the University of California, Merced, in 2008, where she is now a Professor in the Physics Department. Her recent research interests focus on theoretical studies of quantum simulation, superconducting quantum computing, adiabatic processes, optomechanics, hybrid quantum systems, decoherence and noise models.

报告人：Dr. Xian-Xin WuYing Zhao，IAS, Princeton

时间：8月14日（周五）9:30

单位：Kavli Institute for Theoretical Sciences，UCAS

参会方式： Zoom

Online Meeting Room：https://zoom.com.cn/j/96291836802

Meeting ID：962 9183 6802

When Alice shares thermofield double with Bob, her time evolution can make the wormhole grow. We identify different kinds of operations Alice can do as being responsible for the growth of different parts of spacetime and see how it fits together with subregion duality. With this, we give a quantum circuit interpretation of evaporating black hole geometry. We make an analogy between the appearance of island for evaporating black hole and the transition from two-sided to one-sided black hole in the familiar example of perturbed thermofield double. If Alice perturbs thermofield double and waits for scrambling time, she will have a one-sided black hole with interior of her own. We argue that by similar mechanism the radiation gets access to the interior (island forms) after Page time. The growth of the island happens as a result of the constant transitions from two-sided to one-sided black holes.

更多报告信息：中国物理学会期刊网学术讲座列表