1时间门控拉曼技术原理及在纳米材料研究中的应用
报告人：刘玉龙 研究员
时间：3月29日（周二）10:00
单位：中国科学院物理研究所
参会方式：腾讯会议ID：604 503 283
摘要：
在简述拉曼光谱学与光谱仪创新技术与未来发展趋势的基础上，着重介绍利用拉曼信号与荧光信号产生的时间差，将激光激发时间控制在样品拉曼信号产生的时间窗口内，从而达到只收集拉曼散射光谱信号，而拒绝收集时间窗口外的荧光等其它信号的技术-时间门控拉曼技术。利用这技术可获得真正的物质指纹光谱，为了解固体中元激发及它们之间相互作用提供了有效方法。
本报告利用时间门控拉曼技术技术对纳米SnO2颗粒和稀土Nd:GGG、生物组织等材料的测量结果，展示出其在诸多相关领域良好的应用前景。例如，由于克服了荧光的干扰，观察到了纳米SnO2颗粒中的与纳米结构相关特征拉曼模式（表面、界面、高阶拉曼、及吸附模式等）。这些结果突破了以往只关注尺寸变化引起其体相拉曼光谱影响的局限性，为研究纳米晶粒尺寸、微观结构及其振动之间的关系提供了有用的信息。
总之，时间门控拉曼技术是既完成对物质的定性分析，又可进行定位分析的新科技，在物理、化学、生物等领域内有着广泛的应用前景。
报告人简介：
刘玉龙 研究员， 长期从事凝聚态材料的光、磁、电特性的光谱学与技术研究。曾先后主持或参加国家科技部重大仪器设备研制专项、“973”项目、“863” 项目、各类国家自然科学基金项目，中科院专项研究项目。在国内外主要的学术刊物上发表论文180余篇。参加的研究项目先后获得中科院自然科学二等奖、三等奖和国家优秀专利奖等奖项。参与中科院物理所第一台国产化拉曼光谱仪、国内第一台布里渊光谱仪的研制，2015年主持研制成功国内首台研究级显微共聚焦拉曼光谱仪。
2布里渊光散射介绍
报告人：张俊 研究员
时间：3月29日（周二）10:30
单位：中国科学院物理研究所
参会方式：腾讯会议ID：604 503 283
摘要：
布里渊光散射是一种非弹性光散射效应，它描述了光与物质中各种低能元激发的相互作用，本报告主要介绍布里渊光散射的基本原理、最新研究进展和发展趋势、以及我们在布里渊光散射方面开展的工作。
报告人简介：
张俊 研究员，现任半导体超晶格国家重点实验室副主任，中国物理学会光散射专业委员会委员,《光散射学报》和《Jounal of Semiconductors》编委。2015年获国家人才计划，2018年获北京市杰青，2021年获Nano Research Young Innovators Award in 2D Materials。张俊博士在激光冷却半导体、声子边带拉曼冷却、激子-声子耦合、自旋-声子耦合等方面作出重要贡献。已在Nature、Nature Photonics、Nano Letters等在内的期刊上发表论文90余篇，撰写中英文专著3章，授权美国专利3项。论文被引用7000余次，H因子42。
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报告人：Dr. Yuxiang Zhang，Niels Bohr Institute
时间：3月29日（周二）15:00
单位：中科院物理研究所
参会方式：腾讯会议
会议ID: 742-746-617
会议密码：0329
摘要：
If the separation between two atoms is shorter than the resonant wavelength, the light-mediated resonant dipole-dipole interaction (RDDI) will be significant. RDDI is usually long-range, dissipative, and lead to phenomena such as super and sub-radiance. For different light fields, such as the real space electromagnetic field or field engineered by photonic devices, RDDI could have completely different forms. However, in 1D atom arrays with a few atomic excitations, we show that some properties are generic (under some loose conditions) regardless of the underlying light fields. This includes a power-law scaling of the decay rate of the subradiant states, and multiply-excited states interpreted as Jordan-Wigner fermions or Tonks-Girardeau bosons.
报告人简介：
Dr. Yu-Xiang Zhang obtained his bachelor at the School of Gifted Young (00 class) of the University of Science and Technology of China in 2012, and received the PhD degree in quantum information science from the same university in 2016. Then he works as postdoc in Aarhus University and the Niels Bohr Institute of the Copenhagen University till now. He works in the field of quantum information and quantum optics.
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报告人：Dong-Gang Wang，Cambridge University
时间：3月29日（周二）20:30
单位：中国科学院理论物理研究所
参会方式：蔻享直播
会议链接：
摘要：
Correlation functions of primordial fluctuations provide us an exciting avenue into the physics with extremely high energy in the very early Universe. Recently the bootstrap approach has offered new perspectives and powerful tools to study these cosmological correlators. In this talk, by incorporating the latest developments, I will “bootstrap” two types of correlators generated by boost-breaking interactions during inflation, which are most relevant for the next-generation observations. The first one is the contact correlators arising from higher-derivative self-interactions of the inflaton. The second is the cosmological collider physics, where the masses and spins of heavy particles leave unique imprints in the scalar bispectra. Since the boost symmetries are broken in our consideration, the signals of non-Gaussianity are boosted to be detectable for near-future experiments. Furthermore through the bootstrap approach, we derive for the first time not only a complete set of these correlators systematically, but also their full shape information analytically.
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报告人：孙栋，北京大学
时间：3月30日（周三）14:00
单位：清华大学物理系
地点：物理系理科楼C302
摘要：
The experimental manifestation of topological effects in bulk materials under ambient conditions, especially those with practical applications, has attracted enormous research interest. Weyl semimetals and chiral Fermions supply ideal material platforms for such endeavors. The Berry curvature in these materials becomes singular at the node points, creating an effective magnetic monopole in the k-space. Such singular topology can have profound impact on the nonlinear optical response of these materials and it is directly applicable to photodetection. In this talk, we started with our experimental work on the revealing of the singular topology in a type-II Weyl semimetal TaIrTe4 in the photo responses, which is shown to be directly related to the divergence of Berry curvature. As a result of the divergence of Berry curvature at the Weyl nodes, TaIrTe4 exhibits unusually large photo responsivity of 130.2 mA/W with 4-mm excitation in an unbiased field effect transistor at room temperature arising from the third-order nonlinear optical response. We further elucidate such effect is directly applicable to high performance photodetectors based on topological semimetals, especially for long wavelength (low photon energy) range. Some recent progresses along this direction from our group will be discussed. Especially that I will show detectors based on TaIrTe4 are directly sensitive to multiple light parameters, including polarization and orbital angular momentum, in mid-infrared wavelength range.
报告人简介：
孙栋，北京大学量子材料中心长聘副教授，研究员。2004年本科毕业于中 国科学技术大学物理系，2009年博士毕业于密歇根大学超快光科学中心， 然后分别在密歇根大学超快光科学中心和华盛顿大学担任博士后和研究 员，2012年入选海外人才计划青年项目，并受聘北京大学量子材料科学 中心，2017晋升长聘职位，2019年获得北京市杰出青年基金支持。主要 研究方向量子材料的物性以及基于量子材料的光电器件的光谱表征。
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报告人：陈光泽，芬兰阿尔托大学
时间：3月31日（周四）13:30
单位：青年科学半月谈
参会方式：蔻享直播
会议链接：
摘要：
Quantum spin liquids (QSL) are exotic phases of matter featuring strong entanglement and fractional excitations. They have attracted much research interest due to their potential Majorana physics and relation to high-temperature superconductivity. Despite the theoretical interest, challenges remain in the material realization and characterization of QSL. Recently raised magnetic 2D materials such as TaS2 provide a versatile platform to engineer and characterize QSL phases. In particular, inelastic electron tunnelling spectroscopy (IETS) provides a potential local characterization of QSL. Based on these, I will present our proposals on identifying QSL with impurity and twist engineering. In addition, I will show how substrate engineering could potentially drive a magnetic 2D material towards a QSL phase.
报告人简介：
陈光泽，2017年毕业于中国科学技术大学，获理论物理专业学士学位；现在是芬兰阿尔托大学在读博士生。主要研究兴趣为二维磁性材料，量子自旋液体以及它们的实验表征。
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报告人：Michael Kramer，德国马普射电天文研究所
时间：3月31日（周四）15:30
单位：北京大学物理学院
地点：Remote colloquium
摘要：
We experience a golden era in testing and exploring relativistic gravity. Whether it is results from gravitational wave detectors, satellite or lab experiments, radio astronomy plays an important complementary role. Here one can mention the cosmic microwave background, black hole imaging and, obviously, binary pulsars. This talk will provide an overview how these methods relate to each other, and will in particular focus on new results from the study of binary pulsars, where we can test the behaviour of strongly self-gravitating bodies with unrivalled precision. The talk will also give an outlook of what we can expect from new experiments, such as MeerKAT or the SKA.
报告人简介：
Born in Cologne, Michael Kramer graduated Physics in Cologne and Bonn, and obtained a PhD at the University of Bonn in 1995. He was a staff astronomer at MPIfR (1996-1998), a Max-Planck Otto-Hahn fellow at the University of California at Berkeley, first Lecturer and then later Professor at the University of Manchester, Head of the Pulsar Group of the Jodrell Bank Observatory and Associate Director of the Jodrell Bank Observatory. In 2009, he was appointed as Director at the Max-Planck-Institute for Radio astronomy in Bonn, Germany. He is currently President of the German Astronomical Society. His expertise lies in data intensive radio astronomy with a focus on the observations of pulsars for experimental tests of gravitational physics.
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报告人：邹冰松 院士，中国科学院理论物理研究所
时间：4月1日（周五）15:00
单位：北京大学物理学院、核物理与核技术国家重点实验室、北京物理学会
参会方式：蔻享直播
会议链接：
摘要：
本报告将简要回顾强相互作用研究发展过程中诺贝尔物理学奖等里程碑式的研究工作，介绍人类对强相互作用拓展认识的历程及目前相关领域的前沿研究概况。
报告人简介：
邹冰松，理论物理学家，中国科学院院士。主要从事强子物理研究。提出并主持课题组开拓了在北京正负电子对撞机上开展核子和超子激发态研究的新项目，使我国在重子谱这一世界物质微观结构研究的前沿领域占有重要的一席之地；预言了隐含重味的五夸克态存在，并得到实验观测支持；系统研究了标量介子谱，为发现和确立多个标量介子做出重要贡献。已在国内外学术期刊上发表论文600余篇，在国际学术会议上做特邀大会报告40余次；应邀在国际核物理大会（INPC）、粒子与核国际会议（PANIC）、国际少体物理大会（FB）、强子谱和强子结构国际会议（HADRON）等系列国际会议担任国际顾问委员会或程序委员会成员40余次。
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