超導世紀、d波超導能隙對稱性、二維電子系統、石墨烯人造原子 | 本周物理講座

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報告人：曹紫昱，聊城大學

時間：11月11日（周二）10:00

單位：中國科學院物理研究所

地點：懷柔園區X1南樓204會議室
騰訊會議：807-122-628

會議密碼：2025

摘要：

加壓下La3Ni2O7中發現臨界溫度超過77K的超導現象，為研究高溫超導機制建立了一個全新的研究平臺，由此引發了鎳基高溫超導研究的熱潮。盡管La3Ni2O7在高壓下的超導性（體現為零電阻和邁斯納態）已獲實驗證實，然而，其超導能隙結構與配對機制仍屬未解之謎，亟待實驗測定。高壓下觀測超導能隙的主要難度源于材料低超導體積分數和被限制在金剛石壓砧中的有限的樣品尺寸。本研究通過采用高壓定向點接觸譜技術，結合動量分辨能隙探測與高壓環境，以探測鎳基超導體的超導能隙大小與對稱性。接觸點構建在不同晶面所測量的微分電導譜隨偏壓變化呈現V形準粒子隧穿或零偏壓峰，表明其主要具有d波配對對稱性。通過沿c軸制備的4個接觸點測得d波序參數的振幅值所對應的能隙-Tc比2Δ/KbTc = 3.7-4.1。證明La3Ni2O7為d波強關聯超導體。我們的發現填補了鎳基超導體能隙探測的實驗空白，由此闡明了La3Ni2O7的超導配對機制，并為鎳基高溫超導理論模型建立了實驗基準。

報告人簡介：

曹紫昱，男，2013年本科畢業于山東大學，2019年于中國科學技術大學獲理學博士學位，曾在德國DESY同步輻射光源、美國阿貢國家重點實驗室訪問研究。2019年，于韓國成均館大學開展博士后研究工作，2024年3月加入聊城大學，物理科學與信息工程學院，副教授，山東省“泰山學者”青年專家。主要從事極端條件下基于金剛石對頂砧壓機的超導電性研究工作，具有電子強關聯體系的研究背景，研究興趣包括高溫超導，電荷密度波，拓撲絕緣體等。近年來，在高水平期刊Nat. commun.、NPG AsiaMater.、J. Phys. Chem. Lett.、Phys. Rev. B等發表論文20余篇。曾主持韓國教育部國家研究基金2.1億韓元，國自然青年基金，并參與國內外多個科研項目的研究工作。

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報告人：Zhesen Yang

時間：11月11日（周二）14:00

單位：中國科學院物理研究所

地點：M830

摘要：

In this talk, I will introduce a concept we proposed recently, i.e., the complex frequency fingerprint (CFF), which is an experimentally accessible method for detecting the complex frequency Green’s function (GF). Unlike the real frequency GF, where ω is real, this complex frequency GF is shown to play a necessary role in both non-Hermitian and (Hermitian) quantum many-body systems. For non-Hermitian systems, we will prove that our method detects complex energy spectra, eigenstates, and complex frequency GFs throughout the complex plane, providing necessary identification of the non-Hermitian skin effect. For quantum many-body systems, our method reveals quasiparticle peaks across the complex plane and intuitively illustrates interaction effects. This information is difficult to obtain with real frequency detection. Our method paves the way for exploring exotic phenomena in both non-Hermitian and quantum many-body systems, bridging theory and experiment across diverse physical areas.

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報告人： 毛岳，北京大學

時間：11月12日（周三）14:00

單位：中國科學院物理研究所

騰訊會議：984-404-318

會議密碼：1112

摘要：

原子結合構成物質時有兩個重要過程：一是原子間形成化學鍵，二是原子內發生軌道雜化。量子點通過受限效應產生不同軌道的電子受限態，可以模擬真實原子的電子軌道，于是量子點也稱作人造原子。目前，人造原子已經很好地模擬出真實原子間化學鍵的形成。然而，軌道雜化卻未曾被人造原子模擬出來。我們指出人造原子勢場的各向異性可以讓不同受限軌道之間發生雜化。我們具體提出了石墨烯人造原子中橢圓各向異性導致的軌道雜化，這也得到了合作者的實驗證實。另外，我們發現物理起源迥乎不同的回音壁模和原子塌縮態可發生雜化。

報告人簡介：

毛岳博士于2020年獲得北京航空航天大學學士學位，于2025年獲得北京大學博士學位，2025年開始在北京大學物理學院開展博士后研究，合作導師為孫慶豐教授。發表學術論文16篇，其中以第一作者/共同一作/共同通訊作者身份在Nature，Phys.Rev.Lett.，Phys.Rev.B（5篇），ACSNano等期刊發表論文9篇。入選博士后創新人才支持計劃、北京大學博雅博士后項目。

4

報告人：Dr. Jie Wu，Associate professor, Department of Physics,School of Science

時間：11月12日（周三） 15:00

單位：西湖大學

鏈接：

摘要：

This talk reviews the research progress on superconductivity since its discovery in 1911, including advances in the application of superconductors, the theoretical foundations and developments of superconductivity, the history of major discoveries, and emerging directions. It reflects the devoted efforts of generations of scientists in this important field and its current status. Using superconductivity as an example, the talk also illustrates the fascinating landscape of strongly correlated electron physics.

報告人簡介：

Dr. Wu received his B.S. and M.S. from Fudan University and received his Ph.D in experimental condensed matter physics from the University of California at Berkeley. He did his Postdoctoral research at the National High Magnetic Field Laboratory of the USA, Since 2012, he became an Assistant Physicist at the oxide-MBE group at Brookhaven National Laboratory of USA. Then he was promoted to be an Associate Physicist and later a Physicist. In Sep 2019, he joined the Physics Department of Westlake University.

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報告人：Andrey Varlamov, Ph.D.，Pl, institute of CNR-SPIN, ltaly

時間：11月12日（周三） 15:30

單位：西湖大學

鏈接：

摘要：

The lecture begins with the remarkable family background and scientific journey of Nobel Prize laureate Lev Landau. It explores his university years and spirited student life, his intellectual pilarimage throuah the leading centers where quantum mechanics was born, and his development into one of the most briliant theoretical physicists of the 20th century. I will highlight Landau's groundbreaking contributions to quantum mechanics, the theory of phase transitions, superfluidity, superconductivity, and high-energy physics. The second part of the lecture focuses on another side of Landau - the inspiring teacher and founder of the renowned Landau School of Theoretical Physics. As the principal author of the monumental Course of Theoretical Physics, Landau profoundly shaped the education of generations of physicists around the world.

報告人簡介：

Andrey Varlamov obtained his Master's degree cum laude at the Moscow Institute for Physics and Technology in 1977. in 1980, under supervision of Alex Abrikosov, he was awarded Ph.D. degree in Condensed Matter Physics. He worked as a researcher, associate professor, and full professor of the Department of Theoretical Physics of the Moscow Institute for Steel and Alloys (Technological University), then as the fellow at the Condensed Matter Theory Group of Argonne National Laboratory (USA). Since 1999 he has been the principal investigator of the Institute of Superconductivity, innovative Materials, and Devices of the ltalian National Research Council (CNR-SPlN). His main fields of scientific interests are: superconductivity, theory of metals, theory of phase transitions, thermoelectricity, and nanophysics. He is the author/editor of fifteen books, among which is the monograph "Theory of Fluctuations in Superconductors", written in co-authorship with Anatoly Larkin, five monographic review articles, more than 200 scientific papers.

6

報告人：趙世恒，馬克斯-普朗克復雜系統物理研究所

時間：11月12日（周三） 16:30

單位：中國科學院理論物理研究所

地點：北樓322

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報告人：Qingwen Wu，華中科技大學

時間：11月13日（周四）15:30

單位：北京大學物理學院

地點：KIAA-auditorium

摘要：

Both young stars in the central parsec of our Galaxy and super-solar metallicity as found in parsec-scale of broad emission lines of QSOs suggest the presence of stars very close to SMBHs. The stellar process in this extreme environments should be much different from the isolated stars in large-scale galaxy. The tidal disruption events, future space GW detection on extreme mass-ratio inspirals and possible stellar-mass BH merger events in AGN disk will shed light on the unresolved nuclear stellar process in distant galaxies. I will present and discuss the following contents: nuclear stellar process in our Galaxy center; metal enrichment in nuclear region of AGNs; dynamics of stellar-mass BH binary in AGN disk and possible GW features; the possible nuclear stellar process in compact little red dots.

報告人簡介：

Professor in Department of Astronomy in Huazhong University of Science and Technology. I mainly work on AGN physics. In last several years, I try to use multimenssenger to explore the parsec-scale nuclear stellar process near SMBHs in order to understand coevolution of SMBH and galaxy.

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報告人：Danilo Artigas，University of Kyoto

時間：11月14日（周五）14:00

單位：中國科學院理論物理研究所

地點：南樓6620

摘要：

Primordial black holes (PBHs) are a major candidate for dark matter, expected to form from the collapse of large density fluctuations generated during inflation. Their abundance is highly sensitive to non-linear effects, some of which can be described through the δN formalism. This approach models the universe as a set of locally homogeneous patches evolving independently throughout inflation. However, accounting for the spatial correlations between these patches is crucial to predicting the spatial contribution of PBHs and the formation of clusters. In this talk, after reviewing the δN formalism, I will show how to include spatial correlations within this framework. As an illustration, I will discuss the ultra-slow-roll model and compute the curvature perturbation ζ -necessary to determine PBH formation-?and its spatial correlations at the end of inflation. In the future, this could enable the prediction of PBH binaries and clusters, which may leave observable imprints such as gravitational waves.

報告人簡介：

Danilo did a joint PhD between Universtity Paris-Saclay in?France and Jagiellonian University in Poland where he studied aspects of quantum gravity and non-linear effects in cosmology, in particular during inflation, from 2019 to 2023. After that, he joined the Department of Physics of Kyoto University as a JSPS fellow. His main research interest center on cosmological inflation, particularly in the non-linear regime of cosmological perturbations and its relation with Primordial Black Holes and Gravitational Waves.

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報告人： 劉陽，北京大學

時間：11月14日（周五）15:00

單位：北京大學物理學院、北京物理學會

地點：

摘要：

半導體異質結結構不連續的能帶結構會在界面處構成勢阱，并在界面束縛大量的電子形成一個薄層。電子在垂直于界面方向的運動被勢阱束縛而被量子化，而其平行于表面的運動仍然是自由的。這樣的電子薄層被稱為二維電子氣（2DEG）。在極低溫度下（~10 mK），極純凈半導體材料中，電子散射等非理想因素被降至極低。二維電子氣的物理性質完全由電子的動能以及電子間庫侖作用力所決定，并在強磁場的作用下呈現出一系列新穎的量子態。其中包括整數量子霍爾效應（Integer Quantum Hall Effect, IQHE, Klaus von Klitzing, et al. Nobel Physics,1985），分數量子霍爾效應（Fractional Quantum Hall Effect, FQHE,崔琦, et al. Nobel Physics, 1998），Wigner晶體，電荷密度波等等。分數量子霍爾效應是二維電子氣展現的一種獨特的多體量子態(many-body quantum state)。這種穩定的量子態完全由電子之間的相互作用引入。它的內在稟賦蘊含在電子與電子之間的相對拓撲結構。這種拓撲結構的宏觀外在表現展示出超流的特征。

實驗技術是物理研究的基石，新的測量手段和裝置往往會帶來新的物理發現。我們立足于利用最先進的實驗方法研究物理現象，開發和改進了包括電容、表面聲波等在內的多種極低溫測量工具。在突破現有的極限之后，發現了大量新穎的物理現象，加深了我們對于超高遷移率二位電子系統種諸多量子態的理解。

報告人簡介：

劉陽副教授在清華大學電子工程系廖延彪教授指導下獲得學士和碩士學位后，進入普林斯頓大學師從MansourShayegan教授完成博士學習并在2014年獲得博士學位。之后他加入斯坦福大學HariManoharan課題組完成博士后研究，并于2018年入職北京大學物理學院量子材料科學中心。其研究聚焦于利用多種先進實驗方法研究超高遷移率二位電子系統種諸多量子態的動態響應特征。

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