霍爾晶體、硅基量子計算、量子電動力學、系外地球巡天 | 本周物理講座

1

報告人：Dr. Mei Ting Mak，University of Oxford

時間：12月16日（周二）10:00

單位：北京大學物理學院

地點：物理大樓北539教室

騰訊會議：789-354-298

2

報告人：張鑫，慕尼黑工業大學

時間：12月16日（周二）15:00

單位：清華大學物理系

地點：物理樓W260

摘要:

Superradiance stands as a hallmark phenomenon in collective quantum optics. I will show the unraveling of superradiant dynamics into individual quantum trajectories via homodyne detection. Remarkably, despite the presence of entanglement, these trajectories can be effectively treated as product states for describing local observables. This finding drastically simplies the complexity of superradiant phenomona and can lead to fully classcial and exact description in some scenerios, offering both analytical treatment and intuitive understanding. Furthermore, I will show that our approach extends to regimes dominated by subradiant decay. Finally, I will present a novel emergent collective behavior in waveguide QED uncovered by this trajectory-based perspective, which renders superradiance robust to strong disorders.

報告人簡介:

張鑫，現為慕尼黑工業大學博士后，本科畢業于山東大學，博士畢業于杜克大學，主要研究量子光學、開放量子系統與量子多體理論。

3

報告人：賀煜，深圳國際量子研究院/合肥國家實驗室

時間：12月17日（周三）10:00

單位：中國科學院理論物理研究所

地點：南樓6620

摘要:

硅基量子計算是目前比較有潛力的一類量子計算體系。我將簡單介紹硅基量子計算的背景和發展現狀，然后進一步介紹硅基單原子量子計算芯片的系列技術，包括基于掃描隧道顯微鏡氫掩膜直寫技術的單原子級別的直寫，以及基于微波的自旋量子比特調控和射頻單電子自旋讀出技術等。進而，我們將介紹最近基于該技術首次實現的多比特量子糾纏態制備、量子錯誤探測和糾錯、以及邏輯量子比特制備和通用邏輯門，以及在此基礎上首次實現邏輯態的量子算法演示，并最后介紹面向大規模集成量子計算的思路和探索。

報告人簡介:

賀煜，深圳國際量子研究院/合肥國家實驗室研究員，主要研究方向為半導體量子計算、量子模擬、量子芯片。為博士生導師，硅基量子計算團隊帶頭人、國家特聘青年人才、《麻省理工科技評論》評選“35歲以下科技創新35人”、主持多項國家自然科學基金委、科技部和地方項目，工作入選“2019年全球十大量子計算實驗”以及“2017年中國十大科技進展新聞”。共發表30篇SCI論文，含2篇Nature，2篇Nature Photonics，2篇Nature Nanotechnology，10篇Physical Review Letters，2篇Nano Letters等，總引用5500多次，H因子22。

4

報告人：葛健，中國科學院上海天文臺

時間：12月17日（周三）15:00

單位：北京大學物理學院

地點：物理大樓北547教室

騰訊會議：187-565-269

5

報告人：郁海波，University of California Riverside

時間：12月18日（周三）10:00

單位：中國科學院理論物理研究所

地點：南樓6620

摘要:

I will begin with an overview of how cosmic structures form on small scales and how these observations provide unique insights into the nature of dark matter. I will then discuss recent tensions between observations and predictions of the standard cold dark matter framework, which suggest that dark matter may be more complex and dynamic than previously thought. I will highlight possible new-physics solutions, focusing on dark matter self-interactions, and conclude with a look at upcoming observations in the next decade that may decisively reveal the true nature of dark matter.

報告人簡介:

郁海波現任美國加州大學河濱分校物理與天文系正教授，并擔任該校實驗宇宙學中心常務主任。他是浙江象山人，1999年本科畢業于浙江大學，2002年在浙江大學取得碩士學位，2007年在馬里蘭大學獲得博士學位，之后曾在加州大學爾灣分校及密歇根大學從事博士后研究。他的主要研究興趣在粒子物理與天體物理的交叉領域，特別是在天文學觀測數據中尋找新物理的跡象。具體包括如下主題：自相互作用暗物質、小尺度宇宙結構形成的數值模擬和觀測、超大黑洞的形成等。近年來，他及其團隊研究表明自相互作用暗物質理論在從矮星系到星系團尺度上可產生多樣化暗暈結構，這對傳統無碰撞冷暗物質模型在小尺度結構問題上的難點提出了重要替代思路。他發表了近100篇學術論文，被引用13000余次。

6

報告人：Ze-Xun Lin, the University of Cambridge

時間：12月18日（周四）10:30

單位：清華大學物理系

地點：物理樓W105

摘要:

Recent advances in moire materials and cavity quantum electrodynamics have opened new pathways to engineer correlated and topological phases of matter. In this talk, I will present two emerging directions. First, I will discuss our recent theory of Hall crystals in fractionally filled Chern bands, where a Wigner crystal of holes coexists with a topological electron fluid. Using Hartree–Fock calculations in broken-symmetry states, we identify crystalline phases whose electronic structure and transport signatures are consistent with a nontrivial Chern number and with the re-entrant anomalous Hall features observed in twisted MoTe2.Next, I will introduce a mechanism by which a time-reversal-breaking chiral cavity reshapes the exciton spectrum, driving an s-to-p orbital transition in the exciton ground state. This provides a broadly applicable route to cavity-controlled orbital and topological engineering in 2D semiconductors.

I will conclude with earlier work on nonlinear-phonon–induced control of interlayer Dzyaloshinskii–Moriya interactions.

報告人簡介:

Ze-Xun Lin received his B.Sc. in Physics from Nanjing University (2013–2017) and his Ph.D. from the University of Texas at Austin (2017–2023), where he was co-supervised by Gregory Fiete and Allan MacDonald. He was a postdoctoral scholar at UCLA from 2023 to 2025 and is currently a postdoctoral researcher in the Theory of Condensed Matter group at the University of Cambridge. His research focuses on the interplay of correlation and topology in moire quantum materials, cavity-engineered exciton, quantum Hall and superconducting phases, and transport phenomena in frustrated magnetic systems such as pyrochlore spin ice.

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報告人：Ilya Belopolski，Nanyang Technological University

時間：12月18日（周四）14:00

單位：清華大學物理系

地點：物理樓W105

摘要:

Weyl semimetals are crystals where electronic quasiparticles take the form of Weyl fermions. Such emergent Weyl fermions are massless, chiral and topological—potentially useful for circuit interconnects, ultrafast THz detectors and topological transistors. Despite these promising applications and a decade of intense worldwide research, our best Weyl semimetals to date are in fact basically metallic and dominated by irrelevant, conventional electrons. To solve this problem, we took a different approach—we started from the topological semiconductor Bi2Te3 and used Cr doping to introduce ferromagnetism and drive a topological phase transition to a semimetal. We observed that (Cr,Bi)2Te3 exhibits a record bulk anomalous Hall angle > 0.5 (the key figure of merit for a magnetic Weyl semimetal) along with non-metallic conductivity, sharply distinct from known Weyl materials and conventional ferromagnets. Together with theory, our experiments suggest that (Cr,Bi)2Te3 has a simple, semimetallic electronic structure composed of only two Weyl points, without irrelevant electronic states. Improving the crystalline quality should further increase the figure of merit, and could enable a richer exploration of Weyl light-matter interaction and non-linear response. Our design principle could further be broadened to analogous inversion-symmetry-breaking Weyl semimetals, robust up to room temperature, and multiferroic Weyl semimetals. The interplay of momentum-space Weyl topology with real-space magnetic structures such as skyrmions and p-wave helices offers a further rich playground for novel quantum phases of matter.

報告人簡介:

As an undergraduate I developed detectors at the Laser Interferometer Gravitational Wave Observatory in Hanford, Washington (years before the binary black hole merger which won the Nobel Prize!). Then, during a year abroad at the Ecole Polytechnique in Paris I was captivated by the lectures of Antoine Georges on the quantum physics of crystals. So, I switched from astrophysics to condensed matter physics and pursued my Ph.D. at Princeton University with Zahid Hasan. I soon found myself at the frontier of the explosion of interest in Weyl semimetals, driven in part by our group’s discovery in 2015. After my Ph.D. I escaped to Tokyo to work with the renowned Yoshinori Tokura and Naoto Nagaosa, acquiring a new passion for creating quantum materials. I have been honored by the Richard L. Greene Award of the American Physical Society (2021), as well as the Spicer Young Investigator Award of SLAC (California, 2021). I am currently Nanyang Assistant Professor in the School of Electrical & Electronic Engineering at Nanyang Technological University, Singapore.

8

報告人：齊靜波，電子科技大學

時間：12月18日（周四）15:00

單位：北京大學物理學院

地點：物理大樓中212報告廳

摘要:

Intense terahertz (THz) pulses induce transient inversion-symmetry breaking in quantum paraelectric SrTiO3, yet the underlying mechanism remains controversial. Using fields up to ~1.1 MV/cm, we reveal spatially inhomogeneous THz-field-induced second harmonic generation (TFISH) governed by competing lattice and defect dynamics [1]. Short-lived coherent antiferrodistortive (AFD) modes suppress dipole correlations within ~5 ps, while heavily damped soft/AFD modes and a defect-induced low-frequency mode (~0.1-0.3 THz) jointly prevent long-range ferroelectric coherence in oxygen-vacancy-rich regions. Collective modes manifested by oscillatory TFISH components exhibit softening followed by hardening below a critical temperature T*~28 K, confirming transient ferroelectric order where defects are sparse. These results reconcile conflicting interpretations, establish defect-mediated competition as a central regulator of light-induced ferroelectricity, and open routes to ultrafast control of quantum materials.

報告人簡介:

齊靜波，電子科技大學教授。博士畢業于美國Vanderbilt大學，先后在美國強磁場國家實驗室和洛斯阿拉莫斯國家實驗室從事博士后研究工作。主要從事凝聚態體系中的超快光譜和太赫茲光譜研究，聚焦于磁性、拓撲和關聯量子體系在激發態下的超快微觀動力學過程，以及其衍生的相關太赫茲技術方面的應用。相關研究論文發表在Phys. Rev. Lett., Nat. Commun. 等學術期刊上，主持國家自然科學基金重點項目和國家重點研發項目課題等。

9

報告人：Xiaohu Yang，上海交通大學

時間：12月18日（周四）15:30

單位：北京大學物理學院

地點：KIAA-auditorium

摘要:

We are entering a golden age of high-precision cosmology, driven by new-generation large-scale sky surveys (including China's CSST). Galaxy clusters, the universe's largest structures, can be used as powerful "cosmic probes" to illuminate the dominant yet invisible components of the universe: dark matter and dark energy. In this talk, I will present some of our past attempts to find and characterize the galaxy groups/clusters from both large spectroscopic and photometric redshift surveys and their applications in the galaxy formation and cosmological studies. I will also spend some time describing the recent progress of JUST, and its role in the future cluster cosmological probes.

報告人簡介:

Xiaohu Yang, is currently a Distinguished Professor at Shanghai Jiao Tong University, Deputy Director of the Tsung-Dao Lee Institute, and Project Lead of the JUST program. He has been supported by the national talent programs including the National Science Fund for Distinguished Young Scholars, the Cheung Kong Scholars Program, and the National High-Level Talents Special Support Program. His research interests mainly focus on the large scale structure of the universe and galaxy formation. Within this framework, he has established the the conditional luminosity function model for galaxy formations, developed the halo-based group finder to map the cosmic web using galaxies, and initiated the ELUCID project with colleagues to reveal the evolution histories of our local universe.

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報告人：劉進，中山大學物理學院

時間：12月18日（周四）16:00

單位：清華大學物理系

地點：物理樓W101

摘要:

由單個光子和單個原子組成的腔量子電動力學系統是傳統量子物理和現代量子信息技術中的基本單元之一。在半導體芯片上實現人造原子和光學微腔的耦合，可以極大地增強光與物質相互作用強度，縮小器件尺寸，提高系統可擴展性。 本報告將聚焦確定性量子點 - 微腔耦合器件的大規模精準制備。 在此基礎上，我們探索了固態量子光學系統中的新穎物理現象和并進一步構建了高性能的集成化光量子器件。

報告人簡介:

劉進，現任中山大學物理學院教授，博士生導師。2007年和2012年分別獲華南師范大學學士和丹麥科技大學博士學位。之后在丹麥科技大學、美國國家標準與技術研究所從事博士后研究工作。2016年回國任中山大學教授。

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