光电智能计算、二维材料、激光等离子体质子加速器、QGP整体极化 | 本周物理讲座
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报告人：林效，Westlake University
时间：9月24日（周二）12:00
单位：江苏省物理学会
链接：
摘要：
The interplay among frustrated lattice geometry, non-trivial band topology and correlation yields rich quantum states of matter in kagome systems. A series of recent members in this family, AV3Sb5 (A = K, Rb or Cs), exhibit a cascade of symmetry-breaking transitions, involving the 3Q chiral charge ordering, electronic nematicity, roton pair density wave and superconductivity. The nature of the superconducting order is yet to be resolved. Here we report an indication of dynamic superconducting domains with boundary supercurrents in intrinsic CsV3Sb5 flakes. The magnetic field-free superconducting diode effect is observed with polarity modulated by thermal histories, suggesting that there are dynamic superconducting order domains in a spontaneous time-reversal symmetry-breaking background. Strikingly, the critical current exhibits double-slit superconductivity interference patterns when subjected to an external magnetic field. The characteristics of the patterns are modulated by thermal cycling. These phenomena are proposed as a consequence of periodically modulated supercurrents flowing along certain domain boundaries constrained by fluxoid quantization. Our results imply a time-reversal symmetry-breaking superconducting order, opening a potential for exploring exotic physics, for example, Majorana zero modes, in this intriguing topological kagome system.
报告人简介：
Dr. Xiao Lin received his B.S. degree from Zhejiang University (2008), and Ph.D. degree from Zhejiang University (2013). He did his postdoctoral studies at Ecole Supérieure de Physique et de Chimie Industrielles (ESPCI), Paris Tech. from 2013 to 2015. He became a Humboldt postdoctoral research fellow at Cologne University from 2016 to 2018. He joined Westlake University as assistant professor in March 2018. Dr. Lin has rich experience in studying the transport properties of quantum matter, such as polar superconductors, polar metals, chiral superconductors, etc. His current research interests focus on nonlinear optical/transport phenomena, superconducting diode effect, quantum transport and quantum phase manipulation.
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报告人：梁作堂，山东大学
时间：9月24日（周二）15:00
单位：中国科学院理论物理研究所
地点：北楼322
Zoom ID: 832 7630 0290
Passcode: 691240
摘要：
自上世纪七十年代起，高能反应实验发现了一系列意外自旋效应，生出高能自旋物理研究方向。自旋轨道耦合是相对论运动的粒子系统中相互作用的基本特性，强相互作用中的自旋轨道耦合在高能自旋物理中起到了极其重要的作用。高能重离子碰撞过程的整体极化效应是强相互作用自旋轨道耦合的必然结果，理论预言被STAR等大型国际合作实验所证实，为强相互作用理论发展特别是夸克胶子等离子体(OGP)性质的研究开辟了新途径，开启了高能自旋物理研究新方向。本报告将简叙自旋轨道耦合在解释高能反应一系列意外自旋效应中的特殊作用，然后重点介绍高能重离子碰撞过程整体极化效应的基本思想、实验验证以及当前研究的热点。
报告人简介：
梁作堂，山东大学讲席教授。1984年山东大学本科、1987年硕士毕业，1994年在德国柏林自由大学获博士学位，1998年聘为山东大学教授，2002年获教育部跨世纪优秀人才基金资助，2005年获国家杰出青年科学基金资助2009年聘为长江学者奖励计划特聘教授，目前担任粒子物理与粒子辐照教育部重点实验室主任，2018年1月起聘为讲席教授。主要从事强相互作用物理理论研究，研究兴趣包括高能反应过程自旋效应唯象学、核子自旋结构、碎裂过程自旋效应等,与合作者原创性地提出了高能重离子碰撞过程中整体极化效应，为量子色动力学(QCD)相变和夸克胶子等离子体(QGP)性质的研究开辟了新途径;该效应被重大国际合作实验所证实，开辟了QGP自旋物理研究新领域，得到同行高度关注。
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报告人：肖明磊，中山大学
时间：9月25日（周三）10:00
单位：中国科学院理论物理研究所
地点：北楼202
摘要：
Effective operators are the building blocks of effective field theories (EFT), which describe all sorts of interactions among the low energy degrees of freedom under the symmetry constraints. Recent studies manifest the great potential of on-shell techniques for the computations related to effective operators. In this talk, I will show the basic applications of on-shell techniques, including the operator/amplitude correspondence, operator basis construction and the j-basis analysis. In particular, a systematic reduction rule for effective operators is built, which involves a thorough treatment of the field redefinition ambiguity. The rule allows for a clear organization of the results from EFT computations such as matching and running. Future studies on the amplitude construction in EFT may also be introduced.
报告人简介：
肖明磊，主要研究方向为高能物理理论，发表论文19篇，主持博士后面上项目1项。研究领域涵盖粒子物理唯象学、宇宙学、量子引力的全息原理、量子信息、散射振幅与有效场论。近年来在有效场论的散射振幅方法上获得了突破性成果，解决了有效场论算符基的冗余问题。
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报告人：李连忠，香港大学
时间：9月25日（周三）15:00
单位：中国科学院物理研究所
地点：M楼253会议室
摘要：
在先进逻辑器件中随着晶体管尺寸继续缩小，源极漏极隧道效应越加明显，晶体管栅极的可控性变弱。因此，必须减少晶体管本体的厚度以确保有效的栅极控制。如"超薄"的二维半导体等新材料引起了关注。各大半导体公司也加大这一方向的研究力度,我将对二维半导体材料与先进硅基鳍式场效晶体管(FinFET16nm, 7nm)及环绕式栅极晶体管(GAA 1nm)进行电路分析，讨论在先进的技术节点中使用平面二维半导体晶体管优于Si FinFET（或GAA）的好处,包含速度更快,能耗更低等。同时，我们也将讨论2D半导体在材料生长上最关键的缺陷问题，如何能长出高质量符合未来电子学需要的二维半导体，以及制作晶体管的几个关键问题包含金属接触, high-k介电层等等之研究进展情况。
报告人简介：
香港大学机械工程系未来电子讲席教授,香港大学物理系礼任讲席教授,香港大学微电子研究中心主任,前台积电技术研究处处长,英国皇家化学会会士,美国化学会奈米短评(Nano Letters)副编辑。1994及1996年获得台湾大学化学学士(BSc)及硕士(MSc)学位。1997-2002 年间任职于台积电资深研发工程师,2006年英国牛津大学凝态物理博士并加入新加坡南洋理工大学任助理教授,2010年任中央研究院担任副研究员,2014年加入沙特国王科技大学,2016年升任正教授, 2017年底任台积电技术研究处处长, 2021年加入香港大学任讲席教授。研究领域为化学气相沉积CVD和工具设计,器件制造和集成,二维半导体材料生长(石墨烯、氮化硼、二硫化合物等)。目前拥有超过60个美国专利。2018-2023全球高被引学者; 发表>500篇论文, 引用>84000次, H指数134 (AD Sci Index)。
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报告人：董建绩，华中科技大学
时间：9月25日（周三）15:10
单位：北京大学物理学院
地点：物理楼中楼212
摘要：
随着人工智能技术的飞速发展，光计算和光子集成技术、人工智能技术相结合有望解决传统电学计算无法解决的难题，产生颠覆性和变革性技术和应用。本报告从光计算的基本理论出发，重点介绍数字域光计算发展动态和模拟域光计算发展动态，以及人工智能和光计算相结合在产业化应用的前景。
报告人简介：
董建绩，华中科技大学教授、博士生导师，武汉光电国家研究中心主任助理。国家重点研发计划首席科学家，国家杰出青年基金、国家优秀青年基金、全国百篇优秀博士学位论文奖获得者。研究方向是集成光子学和光计算，在光电子领域主流期刊发表论文100余篇，包括Nature Communications、Light Science & Applications、Optica等期刊，入选爱思唯尔中国高被引学者。2次获得湖北省自然科学一等奖，1次获得国家（研究生）教学成果二等奖。担任期刊《Frontier of Optoelectronics》执行主编、全国智能计算标准化委员会委员、中国光学学会纤维光学与集成光学专委会常务委员，作为发起人组织光子学公开课的光电计算专题。
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报告人：郭钰，内蒙古大学
时间：9月26日（周四）10:00
单位：中国科学院理论物理研究所
腾讯会议号：492-378-724
摘要：
Multipartite entanglement includes not only the genuine entanglement but also the k-entanglement (k≥2). It is known that most bipartite entanglement measures have been shown to be monogamous, but the monogamy relation is involved in the bipartite entanglement measures rather than the multipartite ones. Therefore, how to explore the monogamy relation for k-entanglement becomes a basic open problem. In this talk, we introduced an axiomatic definition of the monogamy relation for the k-entanglement measure based on the coarser relation of the system partition. We also present the axiomatic definition of the complete k-entanglement measure and the associated complete monogamy relation according to the framework of the complete multipartite entanglement measure we established in [Phys. Rev. A 101, 032301 (2020)], which is shown to be an efficient tool for characterizing the multipartite quantum correlation as complementary to the monogamy relation associated with the bipartite measure. Consequently, the relation and the difference between monogamy, complete monogamy, and tightly complete monogamy are clearly depicted in light of the three types of coarser relation of the system partition. We then illustrate our approach with two classes of k-entanglement measures in detail. We find that all these k-entanglement measures are monogamous if the reduced function is strictly concave, and they are not completely monogamous, and in general they are not complete.
报告人简介：
郭钰，内蒙古大学数学科学学院教授、博士生导师。主要从事算子理论、算子代数与量子信息交叉领域理论研究。主持在研国家自然科学基金面上项目一项，主持完成国家自然科学基金面上项目、国家自然科学基金青年科学基金项目、中国博士后科学基金项目、山西省自然科学基金面上项目、山西省自然科学基金青年基金项目、山西省留学人员科技活动择优资助项目、山西省高等学校科技创新项目优秀成果培育项目等项目8项。在科学出版社出版专著1部，在 Quantum、Quant. Sci. Tech.、Phys. Rev. A、New J. Phys.、J. Phys. A等杂志发表学术论文50余篇。
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报告人：Prof. David Andelman，Tel Aviv University
时间：9月26日（周四）16:00
单位：中国科学院理论物理研究所
地点：物理所M楼253会议室
摘要：
The Poisson-Boltzmann theory stems from the pioneering works of Debye and Onsageland is considered even today as the benchmark of ionic solutions and electrifield interfaces. lt has been instrumental during the last century in predicting charge distributions and interactions between charged surfaces, membranes, electrodes, macromolecules, and colloids. The electrostatic model of charged fluids, on which the Poisson-Boltzmann description rests and its statistical mechanical consequences have been scrutinized in areat detail. Much less, however, is understood about its probable shortcomings when dealing with various aspects of real physical, chemical, and biological systems. After reviewing the Poisson-Boltzmann theory, l will discuss several extensionsand modifications to the seminal works of Debye and Onsager as applied to ions and macromolecules in confined geometries, These novel ideas include the effect of dipolar solvent molecules, finite size of ions, ionic specificity, surface tension, and conductivity of concentrated ionic soutions.
报告人简介：
David Andelman completed his PhD studies in Physics at MiT in 1984. Between 1984-1987 he was a joliot-Curie post-doc fellow at College de France (in the group of P.G. de Gennes) and at Exxon Research and Engineering (New Jersey). Since 1987 he has been on the faculty of the School of Physics of Tel Aviv University. His interest lies in modeling soft and biological matter within the tools of statistical physics. in recent years, he worked on charged soft matter including polyelectrolytes, ionic liguids and solutions, and charged membranes, exploring their equilibrium and electrokinetic properties.
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报告人：王强华，南京大学
时间：9月26日（周四）16:00
单位：清华大学物理系
地点：理学院郑裕彤大讲堂
摘要：
In this talk, I discuss several remarkable effects when strong electron correlations coexist with electron-phonon coupling. In high-Tc cuprates, the isotope exponent diminishes around optimum doping, but the exponent diverges positively in underdoped and overdoped regimes. We propose a two-boson model, with one of the modes being phonons, and find that the experimental anomalous isotope effect can be nicely explained if both of the boson modes are attractive for d-wave pairing. We substantiate the phenomenological model in by functional renormalization group calculations in a microscopic Hubbard model with Hubbard interaction and various types of optical phonon modes. We find all Holstein-like phonons suppress the d-wave SC, leading to negative isotope effect, while the SSH-type phonons enhance d-wave SC, leading to positive isotope exponent that diverges where Tc itself vanishes, in nice agreement with experiments. We also discuss the effect of strong electron-phonon coupling coexisting with strong electron correlations. We find a rich variety of competing orders in square lattices and Kagome lattices, with either positive or negative isotope effects, shedding lights on possible avenue in achieving higher superconducting transition temperature by utilizing electron-phonon coupling in correlated materials. Wherever applicable, the results are confirmed by quantum Monte Carlo.
报告人简介：
王强华，2002年起任南京大学教授。从事凝聚态理论方面的研究，主要研究方向为强关联电子系统中的超导等物质态的物理性质及其微观机理。提出并命名准粒子散射相干效应；提出和发展处理强关联系统物理的非约束及有限温情况下的重整化平均场方法；提出和发展基于费米子双线性散射模式分解的泛函重整化群方案; 揭示和发现若干强关联体系中的超导微观机理和超导配对特性，以及其它相关磁性和拓扑物质态特性。
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报告人：游智鸿，厦门大学
时间：9月27日（周五）10:00
单位：中国科学院物理研究所
地点：M楼255会议室
摘要：
Liquid-liquid phase separation is a fundamental process that continuously attracts attention from scientists and engineers across diverse disciplines. While the equilibrium theory is well known, the physics of LLPS in nonequilibrium environments is still at its infancy, despite its relevance to microfluidics and cellular systems. In this talk, I will show how activity, particularly active stresses and flows, can remodel the equilibrium physics of LLPS. Fundamentally, we show that activity can introduce many interesting phenomena, including the arrested phase separation, giant interfacial fluctuations, active capillary waves, and activity-induced wetting. Practically, our results offer a generic method to manipulate diverse aspects of LLPS using activity, ranging from the behavior of droplets to the kinetics, structure, and degree of phase separation. Our results highlight the rich new physics of LLPS invoked by activity.
报告人简介：
Dr. Zhihong You is currently a professor at the Department of Physics, Xiamen University. He received his doctorate in physics from Leiden University in 2019. After that, he worked at the University of California Santa Barbara for three years as a postdoc scholar, under the supervision of Prof. M. Cristina Marchetti. In 2022, he started his own group at Xiamen University. He was awarded the National Young Talent Program, and has published in top journals including Science, Science Advances, PRX, PRL, PNAS. He is mainly interested in the theoretical aspects of active, soft&bio matter. His works involve bacterial colonies, active liquid crystals, liquid- liquid phase separation, and nonreciprocal (i.e. violating Newton's 3rd law) systems etc.
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报告人：林晨，北京大学物理学院
时间：9月27日（周五）15:00
单位：北京大学物理学院
地点：物理学院思源多功能厅（西301）
摘要：
在科研领域，激光驱动的高梯度粒子加速器和高亮度辐射源已经成为近几十年的研究热点。通过超强激光脉冲与等离子体相互作用，可以激发起微米尺度的尾波场或是静电分离场，实现高达10 GV/m到TV/m的粒子加速梯度。这种激光等离子体加速避免了真空击穿电场的限制，为加速器的小型化和成本降低提供了新途径，并为探索更高能量区域开辟了可能性。本报告将介绍北京大学团队在激光质子加速优化，束流调控，等离子体诊断技术，以及激光质子刀建设方面的研究进展，并探讨激光加速的超短束流在材料辐照、聚变能源、肿瘤放疗等多领域的应用前景。
报告人简介：
林晨，北京大学物理学院研究员，博士生导师。主要研究方向为激光加速器和加速器控制系统。近五年来，以第一作者/通讯作者在加速器和等离子体领域主流期刊上发表论文三十余篇，获批专利十余项。国家重点研发计划课题“激光加速器控制系统研制和应用平台建设”负责人，获国家自然科学优秀青年基金资助，核学科女性奖，中国物理学会蔡诗东等离子体物理奖，入选ITER计划专项物理人才项目首席科学家。
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