超重核合成、準晶的新奇超導、神經網絡、透射電子顯微學 | 本週物理講座
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報告人:Michał Kowal, National Centre for Nuclear Research
時間:11月12日(週二)10:00
單位:中國科學院理論物理研究所
地點:北樓202
摘要:
I will discuss some of the topics that we are researching and that we are currently interested in in Warsaw. All of them will be related to the physics of superheavy nuclei, where the central goal is to predict the possibility of synthesizing new elements. I'll briefly discuss
- Selected Properties of heaviest nuclei
- Competing Minima & Exotic Nuclear Configurations
- Searching for Extra Stable Systems in SHN
- Nuclear Level Densities
- Reaction Mechanism
- X-sections predictions
報告人簡介:
Prof. Michał Kowal is a theoretical physicist. His scientific interests include the prediction of cross-sections (synthesis probabilities) for existing and planned super-heavy nuclei, as well as stability analysis, including the calculation of lifetimes for the heaviest nuclei. He obtained his Master’s degree and Ph.D. in Physics from Maria Curie-Sklodowska University in 1999 and 2004, respectively. He is currently an associate professor and the head of the Department of Theoretical Physics at the National Centre for Nuclear Research, Poland.
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報告人:楊帆,北京理工大學
時間:11月12日(週二)10:00
單位:中國科學院理論物理所
地點:北樓322
摘要:
The quasicrystal represents a type of long-range-ordered structure which possesses rotational symmetry but is not periodic. The recent revelation of superconductivity (SC) in the Al-Zn-Mg and Ta-Te quasi-crystals (QCs) has aroused great interests. Here, we report our series of works on the electron-electron interaction driven exotic SCs on QCs, including both intrinsic QCs such as the Penrose tiling and extrinsic QCs such as the 45°-twisted bilayel cuprates. We generalize the Kohn-Luttinger mechanism for repulsive interaction-driven SCs from periodic lattices to QCs, and classify the pairing symmetries. Consequently, we found a series of novel superconducting phases such as the chiral SC with spontaneous bulk current, the high-angular-momentum topological SC, the gapless nematic SC with quasinematic vestigial phases, which are unigue to the OCs and absent or rare on periodic lattices. Furthermore, we propose an easily realized approach to obtain the long-sought charge-4e sc by using the extrinsic QCs. Our works open the door to study the exotic SCs on QCs.
報告人簡介:
楊帆,北京理工大學物理學院教授,博士生導師。2002年博士畢業於北京大學物理學院,2004年從清華大學高等研究中心博後出站,之後加入北京理工大學物理學院。2013年被聘爲教授楊帆的主要研究方向爲強關聯和超導理論。在銅基超導、量子自旋液體、鐵基超導、魔角石墨烯、準晶電子態、鎳基超導等領域從事研究多年。發表論文70餘篇,其中包括11篇Phys. Rev. Lett.和1篇 Nat. Commun.,被引用2500餘次。
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報告人:鄭長林,復旦大學物理學系
時間:11月12日(週二)10:00
單位:中國科學院物理所
地點:M255 會議室
摘要:
透射電子顯微鏡是物質科學最重要的微觀結構表徵工具之一。像差校正技術的發展,結合新一代更高性能及功能更強大的電子顯微成像平臺, 爲凝聚態物質的結構表徵提供了卓越的空間分辨率。在本報告中,我們將討論基於像差校正透射電鏡平臺,所發展的系列相干電子成像技術,及其在凝聚態物質研究中的應用。我們將討論利用結構化光闌,實現對相干電子的遠場波前調控,並結合電子共聚焦成像技術,實現新型的三維電子成像表徵。我們並將討論對相干電子在固體中的傳播及散射的精確模擬,以及原子的關聯振動對電子散射的影響,以實現高精度的定量掃描透射成像分析。同時我們還將討論所發展的新型電子波函數相位恢復與測量技術,及以上技術在半導體材料與器件電場與電勢分佈測量中的應用。
報告人簡介:
鄭長林,復旦大學物理學系教授。本科及碩士畢業於南京大學物理系,博士畢業於德國柏林洪堡大學物理系。2010-2017任澳大利亞莫納什大學電鏡中心(MCEM) Research Fellow。2017年底加入復旦大學物理學系,負責雙球差校正透射電鏡平臺的建設與運行,其主要研究方向爲發展與應用基於透射電子顯微鏡的電子散射、成像與譜學分析技術。在Physics Review Letters, Ultramicroscopy, Microscopy, Microscopy and Microanalysis等期刊發表多篇電鏡技術發展的論文,兩次入選PRL編輯推薦亮點論文。2018年,獲澳大利亞顯微學會頒發的John Sanders 獎章,以表彰其在電鏡技術開發及物理學領域的應用所做出的貢獻。
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報告人:Tomasz Cap,National Centre for Nuclear Research
時間:11月12日(週二)11:00
單位:中國科學院理論物理所
地點:北樓202
摘要:
The heaviest known element, oganesson, with an atomic number Z=118, was synthesized in a fusion reaction of a 48Ca projectile with a 249Cf target. Californium is currently the heaviest actinide that can be produced in the quantity necessary for superheavy nuclei synthesis reactions. For this reason, the synthesis of new elements must rely on the use of projectiles made from elements heavier than calcium. Currently, various laboratories around the world are developing or have already developed beams of 50Ti, 51V, and 54Cr. These beams can also be used in reactions with lighter actinides to synthesize new isotopes of known elements.
The results and future prospects of selected experiments, particularly the latest efforts aimed at producing elements with atomic numbers 119 and 120, will be presented. Reactions using 50Ti, 51V, and 54Cr beams, which are considered to have the highest probability of success, will be discussed in detail. Calculations of cross sections, performed within the framework of the Fusion-by-Diffusion (FBD) model, will be presented. The FBD model considers the production cross section as the product of three factors: the cross section for the projectile to overcome the entrance channel barrier (capture cross section), the probability that the resulting system fuses and reaches the compound nucleus configuration, and the probability that the excited compound nucleus survives fission during de-excitation.
報告人簡介:
Dr. Tomasz Cap obtained his PhD at the University of Warsaw, Poland, under the supervision of Prof. Krystyna Siwek-Wilczyńska. His thesis was dedicated to experimental research on 197Au+197Au collisions at an energy of 23A MeV, with an emphasis on projectile and target-like fragment divisions, reaction dynamics, time scales, and neck fragmentation. The experiments were conducted at INFN LNS in Catania, Italy.
Since 2016, Dr. Tomasz Cap is working at the National Centre for Nuclear Research, Poland, in the theory group established by Prof. Adam Sobiczewski, currently led by Dr. hab. Michał Kowal. The group focuses on the properties and production methods of heavy and superheavy nuclei.
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報告人:鄒建新,上海交通大學材料科學與工程學院
時間:11月13日(週三)10:00
單位:中國科學院物理所
地點:M253會議室
摘要:
鎂基材料在儲氫和二次電池領域展現出廣闊前景。在鎂基儲氫材料方面,我們採用表面催化、第二相分散等策略,顯著改善了材料的吸放氫性能,開發出了一系列高性能鎂基儲氫材料,並結合原位表徵和理論計算研究了鎂基複合材料的儲氫機理,揭示了界面處的高活性催化相和納米限域是性能提升的關鍵。在鎂電池正極材料方面,針對Mg²⁺與晶格強靜電相互作用導致的擴散緩慢和電化學性能不佳的問題,我們探索了過渡金屬硫化物的可行性,並開發了與之匹配的電解液體系,再結合原位同步輻射技術和理論計算,探索了硫化物正極材料儲鎂的反應機制,爲高性能鎂電池的設計提供了新的方法和思路。
此外,團隊在鎂基儲能系統的集成與工業應用方面也開展了大量研究工作,成功開發出了全球首輛噸級鎂基固態儲運氫車,製備出了鎂離子軟包電池,驗證了技術可行性。目前,團隊正積極探索更多與鎂基儲能技術適配的應用場景,爲可再生能源利用提供新的解決方案。
報告人簡介:
鄒建新,上海交通大學材料科學與工程學院特聘教授、教育部長江學者、氫科學中心副主任、國家重點研發計劃首席科學家、英國皇家化學會會士、國際先進材料學會會士。主要從事鎂基能源材料方面的基礎研究與應用開發工作,在Science,Adv Mater等國際知名期刊上發表SCI收錄論文180餘篇,已授權國內國際發明專利26項,曾獲中國有色金屬工業技術發明一等獎,國際鎂業協會未來技術獎,上海市技術發明二等獎,國際鎂科學與技術學會年度人物獎,國際能源署Hydrogen TCP獎等。
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報告人:An Tao,中國科學院上海天文臺
時間:11月13日(週三)15:30
單位:北京大學物理學院
地點:KIAA-Auditorium
摘要:
Understanding the formation and evolution of the first supermassive black holes remains one of the most intriguing challenges in modern astrophysics. This talk will focus on three key aspects of early universe AGN studies: radio properties of high-redshift blazars and radio-quiet quasars, examining their jet activity and feedback processes; super-Eddington accretion phenomena observed in both early universe and local AGN populations; and studies of dwarf galaxies as local laboratories for understanding first-generation galaxies. Recent multi-wavelength observations and their implications for black hole growth and cosmic evolution will be discussed, highlighting how these complementary approaches help unveil the nature of the earliest active galaxies.
報告人簡介:
Dr. Tao An is a senior researcher at Shanghai Astronomical Observatory (SHAO), Chinese Academy of Sciences. He currently leads the prototyping of the Chinese SKA Regional Centre. He serves on various academic committees, including the International Astronomical Union (IAU) Radio Commission and the European VLBI Network (EVN) Proposal Review Committee. With over 200 published papers, his research interests focus on high-resolution observational study of compact objects and radio astronomical techniques.
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報告人:戴亞南,南方科技大學
時間:11月13日(週三)15:30
單位:中國科學院物理所
地點:M樓236會議室
摘要:
Exploring the realms of physics that extend beyond thermal equilibrium has emerged as a crucial branch of condensed matter physics research. It aims to unravel the intricate processes involving the excitations, interactions, and annihilations of quasi- and many body particles, and ultimately to achieve the manipulation and engineering of exotic non equilibrium quantum phases on the ultrasmall and ultrafast spatiotemporal scales. In this talk, I will first introduce the ultrafast time-resolved photoemission electron microscopy (tr PEEM) technique as a means of studying non-equilibrium physics in condensed matter materials. Next, I will focus on the discussion of the one of the primary applications of tr PEEM, which is the imaging of surface plasmonic responses, including the coherent vectorial imaging of surface plasmon polariton fields and spin textures, spatiotemporal evolution of localized surface plasmons, as well as plasmon-induced hot electron transport in real space. Finally, I will briefly describe our effect in extending tr-PEEM as a multi dimensional probe for studying excited state physics beyond plasmonics.
報告人簡介:
Yanan Dai is an associate professor in the department of physics, Southern University of Science and Technology (SUSTech). He obtained his B.S. degree at Shandong University in 2013, and Ph.D degree in physics at the University of Pittsburgh in 2019. Before joining SUSTech in Aug. 2022, he worked as a postdoctoral research scientist in the department of chemistry at the Columbia University. His group at SUSTech now is developing advanced ultrafast optical and photoelectron spectroscopies and microscopies, to achieve multi dimensional detection of excited state dynamics and vectorial Floquet engineering of quantum materials on the nano-femto scales.
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報告人:田家驊,華東師範大學
時間:11月14日(週四)15:10
單位:北京大學物理學院
地點:物理學院西樓B105
摘要:
In this talk l will present a new way to calculate the conformal correlators. Via embedding formalism we are able to construct conformal fields in d dimension from Lorentz invariant fields in(d+2) dimension. The correlators are calculated via modern amplitude methods. Potential future applications will be discussed. l will be pedagogical as various aspects of the work may be alien to a broad audience.
報告人簡介:
Jiahua Tian, professor at Department of Physics, East China Normal University. Before that he was a postdoctoral fellowat KlAS and lCTp. His research focuses on string theory, mathematical physics and Al for physics.
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報告人:Hiroyuki Sagawa,RIKEN&University of Aizu
時間:11月14日(週四)15:30
單位:中國科學院理論物理所
地點:北樓202
摘要:
In my talk, I will present ab initio approach to derive charge symmetry breaking interaction based on quantum chromodynamics (QCD). This Interaction is applied to cure the anomaly in the mass difference of mirror nuclei, known as Okamoto-Nolen-Schiffer (ONS) anomaly, which is an old problem but not yet solved by fully microscopic theory. Our approach is intimately related with the partial restoration of the chiral symmetry breaking in nuclear medium and provides a quantitative solution of the ONS anomaly as the mass difference between protons and neutrons in nuclear medium.
Microscopic approach based on QCD is the most challenging ab initio theory for nuclear structure physics. In this respect, QCD sum rule gives a powerful tool, but numerically not highly demanding, to cross a bridge the QCD and hadron spectroscopy such as meson and baryon masses in terms of spontaneous chiral symmetry breaking due to quark condensation. In nuclear medium, a partial restoration of the chiral symmetry breaking is found in the pionic atom experiments. I will discuss some details of QCD sum rule approach and CSB interaction of nucleon-nucleon (NN) interaction sector.
I will also mention the charge symmetry breaking effect in hyper nuclei which is observed recently.
報告人簡介:
Prof. Hiroyuki Sagawa is a theoretical physicist specializing in collective motion in nuclei, spin-isospin excitations, exotic nuclei, charge symmetry breaking in nuclei and hypernuclei. He obtained his Ph.D.in Physics from Tohoku University in 1975, focusing on nuclear theory. He has worked at the University of Tokyo, Utsunomiya University, Niels Bohr Institute, Universié de Paris-Sud, National Institute of Nuclear and High Energy Institute (NIKHEF) at Amsterdam, Michigan State University, and the University of Aizu. Now, he is a Senior Visiting Scientist at RIKEN Nishina Center and a Professor Emeritus at the University of Aizu.
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報告人:王澤朝,南方科技大學
時間:11月15日(週五)14:00
單位:中國科學院物理所
騰訊會議:163-374-936
會議密碼:1115
摘要:
高溫超導現象自三十多年前被發現以來,由其衍生出的豐富物理現象,對現代凝聚態物理的發展產生了極其重要的影響。2012年發現的單層FeSe/SrTiO3界面超導爲高溫超導的研究提供了新的契機。然而,無論是高溫超導體還是界面超導體,都因其複雜的晶格結構和量子多體相互作用,其超導態產生的微觀機理是公認的科學難題,至今依然不完全清楚。如何從亞原子尺度去理解和探測銅氧化物高溫超導體和界面超導體的微觀量子序參量(包括點陣序、電荷序、軌道序、自旋序和拓撲序)將爲理解高溫超導機理提供非常重要的啓發。本報告將討論基於先進的電子顯微學及其發展而來的新方法,總結近年來利用透射電子顯微鏡在高溫超導和界面超導機理研究中的最新進展,並重點討論了其在銅氧化物高溫超導體中對贗能隙態下的拓撲磁結構的發現(Nature, 615, 405-410, 2023),電荷轉移能隙與最大超導轉變溫度的關係(Science, 381, 227-231, 2023)和晶格-聲子相互作用等方面取得的最新研究進展,最後給出了透射電子顯微學在高溫超導和界面超導機理研究中的未來展望。
報告人簡介:
王澤朝博士,2023年6月於清華大學獲博士學位,導師爲:朱靜院士,2023年8月至今,在南方科技大學物理系開展博士後研究,合作導師爲:薛其坤院士。主要的研究興趣是利用先進的電子顯微鏡(透射電鏡和掃描隧道顯微鏡)及其發展出的多種電子顯微學方法,在實空間,原子和亞原子尺度,直接探測複雜高溫超導材料體系和界面超導體系中的點陣、電荷、自旋、軌道和拓撲等基本序參量,以揭示與高溫超導機理有關的重要謎題。近年來,以第一作者身份在Nature, Science和Nature Materials發表相關論文3篇。2024年至今,主持國家自然科學基金青年項目,入選2024年度博士後創新人才支持計劃。
封面圖片來源:https://zhuanlan.zhihu.com/p/625294510
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