二維量子材料、全息凝聚態、自旋—費米子增強耦合、分子手性 | 本周物理講座

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報告人：Akash Singh，University of the Witwatersrand

時間：7月14日（周二）10:00

單位：中國科學院理論物理研究所

地點：南樓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.

報告人簡介:

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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報告人：Prof. Artur Ekert，英國皇家學會院士、中國科學院外籍院士

時間：7月14日（周二）10:00

單位：中國科學技術大學　國際合作與交流部 | 中國科學院量子信息與量子科技創新研究院

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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.

報告人簡介:

Artur Ekert教授是英國物理學家，量子計算領域的先驅、量子密碼學奠基人之一。現任英國牛津大學及新加坡國立大學教授，同時擔任英國皇家學會院士、歐洲科學院院士、新加坡國家科學院院士及中國科學院外籍院士。

他長期專注于量子計算與量子信息理論研究，積極推動量子技術的實際應用。其開創性貢獻在于提出基于糾纏的量子密碼學，不僅革新了密碼學理論體系，更引領了量子通信技術的發展。他將多項量子光學技術引入密碼學領域，為量子密碼學的實用化奠定了堅實基礎。

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

時間：7月14日（周二）15:00

單位：中國科學院物理研究所

地點：M樓238會議室

摘要:

The discovery of the post-perovskite transition in MgSiO? 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.

報告人簡介:

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

時間：7月15日（周三）9:00

單位：北京大學物理學院

地點：物理學院中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.

報告人簡介:

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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報告人：余洋，University of Michigan

時間：7月15日（周三）10:00

單位：中國科學院理論物理研究所

地點：南樓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.

報告人簡介:

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

時間：7月15日（周三）14:00

單位：中國科學院物理研究所

地點：M樓253會議室

騰訊會議ID：234-323-086

會議密碼：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.

報告人簡介:

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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報告人：蔡崢，清華大學

時間：7月15日（周三）14:30

單位：《中國科學：物理學力學天文學》期刊

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摘要:

報告介紹高紅移星系生態系統、宇宙學和人工智能賦能天文數據處理。通過詹姆斯·韋布空間望遠鏡（JWST）的驗證，該算法成功識別出先前無法探測的特征。我會在talk中，介紹目前早期星系宇宙學的前沿問題，以及目前AI賦能的新突破，并探討未來大型設備在AI賦能下的全新發展與潛力。

報告人簡介:

蔡崢，清華大學天文系長聘副教授，系副主任，清華大學深空技術中心主任。他于2015年獲得亞利桑那大學理學博士學位，2015-2019年在加州大學工作。2019年加入清華大學，致力于宇宙早期星系研究。主持國家自然基金委青年A類項目，國家重點研發計劃等，榮獲第六屆“科學探索獎”、清華大學學術新人獎，入選美國國家航空航天局（NASA）哈勃學者（HubbleFellowship）。并主演了勵志紀實紀錄電影《大學》。以第一或通訊作者多次發表于《科學》《自然-天文學》等國際知名雜志。他正在領導建設國際最大光譜巡天設備：寬視場巡天望遠鏡（MUST）。

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報告人：林君浩，南方科技大學物理系

時間：7月16日（周四）10:00

單位：中國科學院物理研究所

地點：M253會議室

摘要:

二維量子材料因其維度受限、界面主導和強關聯效應，常呈現出豐富而脆弱的量子態，如鐵電、鐵磁、拓撲相、相變態及非晶有序結構等。這些量子態往往對外界環境和表征條件高度敏感：一方面，許多低維材料具有顯著的水氧敏感性，暴露于空氣中即可能發生氧化、水解、結構重構或本征相破壞；另一方面，其弱鍵合、低維結構和亞穩量子態又使其量子態失效，同時極易在高能電子束輻照下產生缺陷、相變、無序化甚至結構坍塌。因此，如何在最大限度保持材料本征結構和量子態的前提下，實現原子尺度成像、結構解析及外場調控過程的動態表征，是二維量子材料透射電鏡研究中的核心難題。本報告將介紹我們課題組圍繞低維量子材料與敏感功能材料發展的一系列極限條件透射電鏡表征技術。通過結合冷凍電鏡、氛圍保護球差校正電鏡以及基于 MEMS 芯片的原位透射電鏡方法，我們建立了面向水氧敏感、電子束敏感及外場響應體系的低損傷、原位化和動態化表征策略。相關研究實例包括水氧敏感全有機晶體、有機-無機復合鈣鈦礦的晶格結構解析，單層非晶碳、非共線鐵電、二維鐵磁等易劣化體系的無損定量原子尺度構效關系研究，以及 MoTe? 等可逆相變材料在電流/電壓誘導下動態相變過程的精確測定。

報告人簡介:

林君浩教授，南方科技大學物理系副系主任，黨委書記，量子功能材料全國重點實驗室常務副主任。主要研究興趣為透射電子顯微學新技術與新方法的發展，以及新型低維量子材料的微觀量子物態的精確測量及缺陷對宏觀量子物性的影響。近5年來，在Nature，Science等高影響期刊發表170余篇文章，總引用次數超過20000多次，H因子64。主持國自然青A與重點等項目，入選《麻省理工科技評論》“35 歲以下科技創新 35 人”2021中國區榜單，2022年獲廣東省青年五四獎章提名獎，2023-2025入選愛思唯爾中國高被引學者（物理）。

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報告人：王鵬，國家能源集團首席專家（催化領域）

時間：7月16日（周四）15:00

單位：中國科學院物理研究所

地點：M255

摘要:

煤基合成氣轉化技術是實現煤炭清潔高效利用的重要途徑，包含煤間接液化 (煤制油) 與煤基合成氣制高端化學品兩類技術。傳統煤基合成氣轉化技術存在碳效率低，CO2選擇性過高，催化活性低的共性瓶頸問題，限制了煤間接液化技術穩定性與經濟性，阻礙了煤基合成氣制高端化學品技術的工業化。針對上述共性問題，本研究通過催化劑設計構建、多維動態原位表征、原位電鏡學、動力學分析、理論計算等研究手段，融合基礎理論及工程科學，變革傳統鐵催化劑的主體活性相，形成純相碳化鐵催化新理論，突破鐵催化劑碳效率限制，本質性提升催化劑活性與選擇性，研究放大規律與規模化化核心方法，開發2項新型煤炭清潔高效轉化技術：(1)低CO2選擇性、高穩定性煤間接液化催化劑技術；及(2)高碳效率、高活性合成氣直接制線性α-烯烴技術，并實現了工業應用。

報告人簡介:

王鵬，國家能源集團首席專家（催化領域），國能集團研究總院（北京低碳清潔能源研究院）定向合成催化部負責人，長江學者（校企聯聘）；兼任天津大學教授，博導，“十四五”重點研發計劃項目催化劑研發及工業化負責人。原創“純相碳化鐵催化體系”，基于該體系開發2項高碳效率合成氣轉化技術。發表SCI論文20余篇，英文獨著1部，英文合著1部，申請發明專利130余件，國際專利24件。獲中國專利金獎，石化聯合會青年創新獎，工信部、國資委重點產品、工藝“一條龍”應用示范，工信部、國資委產業優秀基礎創新成果，中國科協“科創中國”先導技術等獎項。

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報告人：劉純驍，上海交通大學

時間：7月17日（周五）15:00

單位：中國科學院物理研究所

地點：物理所M樓253會議室

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.

報告人簡介:

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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