二维量子材料、全息凝聚态、自旋—费米子增强耦合、分子手性 | 本周物理讲座

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报告人：Akash Singh，University of the Witwatersrand

时间：7月14日（周二）10:00

单位：中国科学院理论物理研究所

地点：南楼6620

摘要:

The phase structure of QCD at finite baryon chemical potential remains one of the most elusive problems in strongly coupled gauge theory. Low-temperature, high-density regimes are expected to host a hierarchy of order parameters such as quark bilinears, diquark pairings, and multi-quark condensates, but the lattice sign problem and the breakdown of perturbation theory obscure first-principles access to the resulting phase diagram. Effective field theories illuminate individual phases but cannot adjudicate the competition between them.

We address this question using gauge/gravity duality as a controlled nonperturbative laboratory. Building on the universal structure of holographic superconductor backgrounds, we study a five-dimensional bulk model with two charged scalars dual to operators carrying different baryon charges and scaling dimensions. Each scalar wants to condense at a finite chemical potential, and the question is what happens when they both can: does one win, or do they coexist?

Scanning the space of operator charges and dimensions and working in both confined and deconfined phases, we map the full phase diagram in the temperature and chemical potential plane. Coexistence appears in a finite region of parameter space. Elsewhere, one condensate generically suppresses the others. This suggests that the coexistence of multiple order parameters is rare and governed by simple selection rules on operator data, constraining symmetry-breaking patterns across a wide class of holographic systems with several charged sectors well beyond the QCD setting that motivated us.

报告人简介:

Akash Singh is currently a Postdoctoral Research Fellow at the University of the Witwatersrand, Johannesburg since February 2026. Before that, he completed his Integrated Ph.D. from the Indian Institute of Science Education and Research (IISER) Mohali in June 2025 under guidance of Dr. K.P. Yogendran. He also completed his MS (Physics Major) in 2020 from IISER Mohali. His research focuses mainly on the QCD phase diagram, its application in compact stars, and the holographic approach to AdS/QCD.

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报告人：Prof. Artur Ekert，英国皇家学会院士、中国科学院外籍院士

时间：7月14日（周二）10:00

单位：中国科学技术大学　国际合作与交流部 | 中国科学院量子信息与量子科技创新研究院

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摘要:

The quantum age is nearly upon us, and it promises to transform the way we process, communicate and protect information. But what will this transformation mean for security? Will quantum technologies bring the end of privacy as we know it, or can they offer new ways to defend it? Remarkably, recent advances in quantum cryptography point to the latter. They show that secure communication can remain possible even against adversaries equipped with superior technological powers. More strikingly still, they suggest that security can be guaranteed even when the very devices used for protection cannot be fully trusted. This lecture will explore how emerging quantum technologies are reshaping our understanding of information security, from the threats posed by quantum computers to the new forms of protection made possible by quantum physics itself.

报告人简介:

Artur Ekert教授是英国物理学家，量子计算领域的先驱、量子密码学奠基人之一。现任英国牛津大学及新加坡国立大学教授，同时担任英国皇家学会院士、欧洲科学院院士、新加坡国家科学院院士及中国科学院外籍院士。

他长期专注于量子计算与量子信息理论研究，积极推动量子技术的实际应用。其开创性贡献在于提出基于纠缠的量子密码学，不仅革新了密码学理论体系，更引领了量子通信技术的发展。他将多项量子光学技术引入密码学领域，为量子密码学的实用化奠定了坚实基础。

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报告人：Renata M M Wentzcovitch, Department of Applied Physics and Applied Mathematics, Columbia University, USA

时间：7月14日（周二）15:00

单位：中国科学院物理研究所

地点：M楼238会议室

摘要:

The discovery of the post-perovskite transition in MgSiO₃ provided a compelling explanation for the D'' seismic discontinuity at the base of Earth's mantle. However, subsequent studies showed that iron and aluminum broaden the bridgmanite–post-perovskite transition over too large a pressure interval for it to generate the observed sharp seismic reflector, creating a long-standing paradox.

In this talk, I will show how this paradox is resolved when the transition is treated as part of the complete pyrolitic assemblage rather than as an isolated silicate phase transformation. First-principles thermodynamic calculations combined with phase-equilibrium modeling demonstrate that the Fe²⁺ spin crossover in ferropericlase redistributes iron away from bridgmanite, substantially sharpening the onset of post-perovskite. The coupled evolution of phase proportions, Fe-Mg partitioning, and spin state creates a narrow reaction-relaxed coexistence region with an anomalously soft bulk modulus. These results provide a new thermodynamic framework for reassessing the geophysical manifestations of the post-perovskite transition in the deep mantle.

报告人简介:

Renata Wentzcovitch is a Professor in the Applied Physics and Applied Mathematics Department in the School of Engineering and Applied Sciences and in the Department of Earth and Environmental Sciences at Lamont Doherty Earth Observatory, Columbia University, USA. She obtained a PhD in Condensed Matter Physics from UC Berkeley. She did postdocs in the Physics Department at Stony Brook University in the US and in the Cavendish Laboratory at Cambridge University in the UK. Until 2016, she was a Professor in the Department of Chemical Engineering and Materials Science at the University of Minnesota. Her research focuses on developing and applying ab initio quantum-mechanical methods to study materials under extreme pressure and temperature conditions of planetary interiors. She is a member of the American Academy of Arts and Sciences, a Fellow of the American Physical Society, American Association for the Advancement of Science. She received the Humboldt Award for Senior US Scientist, the Heraeus Professorship Award of Goethe University Frankfurt, and the Bridgman Award of the International Association for Advancement of Research in High Pressure Science and Technology (AIRAPT). She was Chair of the Division of Computational Physics of the American Physical Society.

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报告人：Prof. DSc. Dr. Marcelo Ciappina, Guangdong Technion-Israel Institute of Technology

时间：7月15日（周三）9:00

单位：北京大学物理学院

地点：物理学院中215教室

摘要:

Do you ever wonder about the quantum-electrodynamics side of strong-field laser physics? Strong laser–matter interactions have been a central topic since high-power lasers emerged about half a century ago. They underpin foundational work in atomic, molecular, and optical physics and have helped shape areas such as attosecond science, nonlinear optics, and ultrafast optoelectronics. Although many results can be described using classical electromagnetic fields, recent fully quantized approaches suggest new directions worth exploring. This seminar surveys efforts to treat intense laser–atom interactions within a fully quantized framework. We discuss how such methods can enable the generation of controllable, high-photon-number entangled coherent states and coherent-state superpositions—capabilities that are difficult to capture within semiclassical theories. We then apply the formalism to processes including high-harmonic generation and above-threshold ionization, highlighting features that do not appear in purely classical descriptions. Finally, we consider how these ideas might extend to more complex materials and what they could mean for emerging quantum technologies, especially at the intersection of attosecond physics and quantum information science.

报告人简介:

DSc Dr Marcelo Ciappina completed his PhD in Physics at Balseiro Institute, Argentina, in March 2005 and the Research Professor in Physico-Mathematical Sciences (DSc) dissertation (Habilitation) at the Czech Academy of Sciences, Czech Republic in June 2019. After several years of Postdoctoral and Senior positions all around the world, including, amongst others, various Max Planck Institutes in Germany (MPI-K Heidelberg, MPQ Garching and MPI-PKS Dresden), the Institute of Photonic Sciences (ICFO) in Spain, the Extreme Light Infrastructure (ELI)-Beamlines in Czech Republic, the Institute of High Performance Computing (IHPC) (A* STAR, Singapore) and the Auburn University (USA), he joined the GTIIT in fall 2020 as an Associate Professor and was promoted to Full Professor and granted tenure in January 2025. DSc Dr Marcelo Ciappina is a top-class expert in theory and numerical simulations of nonlinear laser interactions with atoms, molecules, and complex systems.

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报告人：余洋，University of Michigan

时间：7月15日（周三）10:00

单位：中国科学院理论物理研究所

地点：南楼6520

摘要:

We perform a fluctuation analysis of the pairing interaction in the hole-doped Hubbard model within the dynamical cluster approximation. Our analysis reveals that spin-fluctuation-mediated pairing differs qualitatively in the over- and underdoped regimes. In the underdoped regime, we show that the spin-fermion coupling exhibits a pronounced node–antinode dichotomy and mediates a strong attractive interaction between antinodal fermions. This explains why superconductivity persists at underdoping in the Hubbard model and cuprate materials, despite the lack of coherent quasiparticle excitations in the pseudogap regime.

报告人简介:

Yang Yu recently received his Ph.D. from the University of Michigan under the supervision of Prof. Emanuel Gull. He will soon join Prof. Karsten Held’s group at the Vienna University of Technology as a postdoctoral researcher.

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报告人：Dr. Tianwei Duan, City University of Hong Kong

时间：7月15日（周三）14:00

单位：中国科学院物理研究所

地点：M楼253会议室

腾讯会议ID：234-323-086

会议密码：0715

摘要:

Chirality is more than a molecular label: it can emerge through symmetry breaking, be stabilized by collective organization, and govern material properties across multiple length scales. In this talk, I will present my efforts to understand and harness chirality in nanostructured materials and perovskite optoelectronics. I will first introduce our studies of spontaneously chiral nanoparticles, in which achiral building blocks evolve into chiral assemblies through emergent symmetry breaking. These systems provide a platform for investigating how chiral states are generated, selected, and locked in, and how nanoscale chirality can be translated into optical and functional responses. Building on this foundation, I will then discuss enantiomeric packing at perovskite heterointerfaces. Rather than treating enantiomers as interchangeable mirror images, we explore how homochiral and heterochiral configurations give rise to distinct packing motifs, intermolecular cohesion, and interfacial energy landscapes. Such differences can influence molecular ordering, interfacial mechanics, and degradation pathways in perovskite-based devices. These studies suggest that chirality is not merely an additional molecular functionality, but a versatile design parameter for controlling symmetry breaking, molecular packing, interfacial mechanics, and degradation kinetics in functional materials. I will conclude by discussing how this enantiomeric perspective may open broader opportunities for the design of robust materials and optoelectronic technologies.

报告人简介:

Tianwei Duan is an Assistant Professor in the Department of Materials Science and Engineering at City University of Hong Kong. She received her Bachelor’s and Master’s degrees in Chemistry from Tongji University in 2012 and 2015, and completed her PhD in Chemistry at Shanghai Jiao Tong University in 2021 under the supervision of Prof. Shunai Che, where she developed chiral semiconductor nanocrystals. From 2021 to 2024, she was an RGC-funded Postdoctoral Research Fellow at Hong Kong Baptist University, working with Prof. Yuanyuan Zhou on chiral perovskite materials for energy devices. Before joining CityUHK, she served as a Research Assistant Professor in the Department of Chemical and Biological Engineering at the Hong Kong University of Science and Technology. She holds two patents, has contributed two book chapters, and has published 16 papers as first or corresponding author in leading journals including Science, Nature Reviews Clean Technology, Chem, Advanced Energy Materials, and ACS Energy Letters.

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报告人：蔡峥，清华大学

时间：7月15日（周三）14:30

单位：《中国科学：物理学力学天文学》期刊

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摘要:

报告介绍高红移星系生态系统、宇宙学和人工智能赋能天文数据处理。通过詹姆斯·韦布空间望远镜（JWST）的验证，该算法成功识别出先前无法探测的特征。我会在talk中，介绍目前早期星系宇宙学的前沿问题，以及目前AI赋能的新突破，并探讨未来大型设备在AI赋能下的全新发展与潜力。

报告人简介:

蔡峥，清华大学天文系长聘副教授，系副主任，清华大学深空技术中心主任。他于2015年获得亚利桑那大学理学博士学位，2015-2019年在加州大学工作。2019年加入清华大学，致力于宇宙早期星系研究。主持国家自然基金委青年A类项目，国家重点研发计划等，荣获第六届“科学探索奖”、清华大学学术新人奖，入选美国国家航空航天局（NASA）哈勃学者（HubbleFellowship）。并主演了励志纪实纪录电影《大学》。以第一或通讯作者多次发表于《科学》《自然-天文学》等国际知名杂志。他正在领导建设国际最大光谱巡天设备：宽视场巡天望远镜（MUST）。

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报告人：林君浩，南方科技大学物理系

时间：7月16日（周四）10:00

单位：中国科学院物理研究所

地点：M253会议室

摘要:

二维量子材料因其维度受限、界面主导和强关联效应，常呈现出丰富而脆弱的量子态，如铁电、铁磁、拓扑相、相变态及非晶有序结构等。这些量子态往往对外界环境和表征条件高度敏感：一方面，许多低维材料具有显著的水氧敏感性，暴露于空气中即可能发生氧化、水解、结构重构或本征相破坏；另一方面，其弱键合、低维结构和亚稳量子态又使其量子态失效，同时极易在高能电子束辐照下产生缺陷、相变、无序化甚至结构坍塌。因此，如何在最大限度保持材料本征结构和量子态的前提下，实现原子尺度成像、结构解析及外场调控过程的动态表征，是二维量子材料透射电镜研究中的核心难题。本报告将介绍我们课题组围绕低维量子材料与敏感功能材料发展的一系列极限条件透射电镜表征技术。通过结合冷冻电镜、氛围保护球差校正电镜以及基于 MEMS 芯片的原位透射电镜方法，我们建立了面向水氧敏感、电子束敏感及外场响应体系的低损伤、原位化和动态化表征策略。相关研究实例包括水氧敏感全有机晶体、有机-无机复合钙钛矿的晶格结构解析，单层非晶碳、非共线铁电、二维铁磁等易劣化体系的无损定量原子尺度构效关系研究，以及 MoTe₂ 等可逆相变材料在电流/电压诱导下动态相变过程的精确测定。

报告人简介:

林君浩教授，南方科技大学物理系副系主任，党委书记，量子功能材料全国重点实验室常务副主任。主要研究兴趣为透射电子显微学新技术与新方法的发展，以及新型低维量子材料的微观量子物态的精确测量及缺陷对宏观量子物性的影响。近5年来，在Nature，Science等高影响期刊发表170余篇文章，总引用次数超过20000多次，H因子64。主持国自然青A与重点等项目，入选《麻省理工科技评论》“35 岁以下科技创新 35 人”2021中国区榜单，2022年获广东省青年五四奖章提名奖，2023-2025入选爱思唯尔中国高被引学者（物理）。

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报告人：王鹏，国家能源集团首席专家（催化领域）

时间：7月16日（周四）15:00

单位：中国科学院物理研究所

地点：M255

摘要:

煤基合成气转化技术是实现煤炭清洁高效利用的重要途径，包含煤间接液化 (煤制油) 与煤基合成气制高端化学品两类技术。传统煤基合成气转化技术存在碳效率低，CO2选择性过高，催化活性低的共性瓶颈问题，限制了煤间接液化技术稳定性与经济性，阻碍了煤基合成气制高端化学品技术的工业化。针对上述共性问题，本研究通过催化剂设计构建、多维动态原位表征、原位电镜学、动力学分析、理论计算等研究手段，融合基础理论及工程科学，变革传统铁催化剂的主体活性相，形成纯相碳化铁催化新理论，突破铁催化剂碳效率限制，本质性提升催化剂活性与选择性，研究放大规律与规模化化核心方法，开发2项新型煤炭清洁高效转化技术：(1)低CO2选择性、高稳定性煤间接液化催化剂技术；及(2)高碳效率、高活性合成气直接制线性α-烯烃技术，并实现了工业应用。

报告人简介:

王鹏，国家能源集团首席专家（催化领域），国能集团研究总院（北京低碳清洁能源研究院）定向合成催化部负责人，长江学者（校企联聘）；兼任天津大学教授，博导，“十四五”重点研发计划项目催化剂研发及工业化负责人。原创“纯相碳化铁催化体系”，基于该体系开发2项高碳效率合成气转化技术。发表SCI论文20余篇，英文独著1部，英文合著1部，申请发明专利130余件，国际专利24件。获中国专利金奖，石化联合会青年创新奖，工信部、国资委重点产品、工艺“一条龙”应用示范，工信部、国资委产业优秀基础创新成果，中国科协“科创中国”先导技术等奖项。

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报告人：刘纯骁，上海交通大学

时间：7月17日（周五）15:00

单位：中国科学院物理研究所

地点：物理所M楼253会议室

摘要:

Topological superconductivity can host Majorana zero modes at the defects or boundaries of the system. These zero modes are Ising anyons that obey the exotic non-Abelian exchange statistics and can be used to implement error-resilient topological quantum computing. In recent years, quantum-dot-superconductor array has emerged as a new and promising platform for realizing topological Kitaev chains and Majorana zero modes. In this talk, I will talk about our theoretical proposals for how to create a highly tunable Kitaev chain and find Majoranas in double quantum dots, and also proposals for scaling up the system. Our emphasis will be on the crucial role of Andreev bound states acting as a coupler. In parallel, I will also review the recent progress in Kitaev chain experiment. If time permits, I will discuss the possible new directions in this field.

报告人简介:

Chun-Xiao Liu did his undergraduate study in the department of physics at Fudan University during 2008-2012. He obtained the PhD degree in condensed matter theory in University of Maryland in 2018, under the joint supervision of Prof. Jay D. Sau and Prof. Sankar Das Sarma. He then moved to QuTech, Delft University of Technology, the Netherlands to work as a postdoc, before being promoted as a permanent researcher in 2023. In 2025, he joined Tsung-Dao Lee Institute, Shanghai Jiao Tong University as a tenure-track associate professor. His research interest covers topological phases of matter, mesoscopic physics, quantum device physics, and topological quantum computing.

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