重離子加速、水界面超快動力學、QCD、量子維度約化算法 | 本週物理講座

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報告人：Luis A. Orozco, University of Maryland and NIST

時間：7月2日（週二）10:00

單位：清華大學物理系

地點：理科樓C302

摘要：

Francium, discovered eighty-five years ago by Margarite Perey, is the heaviest alkaline atom. It is the most unstable element of the first 103 on the periodic table, and its longest halflived isotope lasts 20 minutes. At any given time, there are only a few grams distributed throughout the earth because it is the product of the decay of uranium and thorium. In-line laser trapping and cooling with an accelerator has made it available for precision spectroscopy. With my students and collaborators, we have dedicated thirty years to its spectroscopic study because its atomic and nuclear structure makes it an ideal laboratory to study the weak interaction. I will present our proposal to better understand the weak interaction at low energy, preliminary measurements of the forbidden M1 transition between states 7S to 8S, and progress towards weak interaction studies (parity violation, time violation) at TRIUMF, the Canadian subatomic physics laboratory in Vancouver.

報告人簡介：

Luis Adolfo Orozco was born in Guadalajara, Mexico in 1958. He completed his engineering studies at the Instituto Tecnológico y de Estudios Superiores de Occidente in Guadalajara, Mexico and his postgraduate studies in physics at the University of Texas at Austin, obtaining his doctorate in 1987. He held a postdoctoral position at Harvard, passing part of this one at CERN, Switzerland. He returned to the United States and worked from 1991 to 2003 as a professor in the physics department of the State University of New York at Stony Brook. From 2003 to 2020 he was professor of physics at the University of Maryland in College Park, MD, USA, where he co-directed the Physics Frontier Center of the Joint Quantum Institute com 2008 to 2019. Since 2021 he is Emeritus Professor. Throughout his career Dr. Orozco has been Guggenheim Fellow (1998), Fellow of the American Physical Society (2000) Fellow of the Optical Society of America (2003), Fellow of the Institute of Physics, UK (2005), Distinguished Traveling Lecturer of the American Physical Society (2002-2025) and corresponding member of the Academia Mexicana de Ciencias since (2005). He has an Honoris Causa Doctorate from INAOE, Mexico (2016). He has graduated 23 PhD students (3 from Mexico) and more than 60 undergraduates (35 from Mexico) have worked in his group. Together with his students and collaborators he is author of more than 100 publications. As a researcher, he is interested in quantum optics, quantum information, fundamental symmetry tests, and high precision spectroscopy. Among his most recognized studies are the trapping and spectroscopy of Francium for weak – interaction studies and the field intensity correlations in quantum optics. http://www.physics.umd.edu/rgroups/amo/orozco/index.html

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報告人：王鵬傑，亥姆霍茲德累斯頓羅森多夫研究中心

時間：7月2日（週二）16:00

單位：中國科學院理論物理研究所

地點：南樓6620

騰訊會議：494-135-619

摘要：

In recent years, the demonstration of accelerating heavy ions from relativistic plasmas to energies, which are conducive for many applications, really stand for the maturity of Laser plasma acceleration (LPA) to be capable of accelerating nearly all kinds of particles like what traditional accelerators can do. Moreover, such heavy ion beams driven by lasers have some unique features that traditional accelerators do not have, which provide an additional tool/platform to study nuclear physics, laboratory astrophysics, high-energy-density physics and cancer therapy.

報告人簡介：

Dr. Pengjie Wang is currently a postdoctoral researcher at Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Germany. Before that, he was a postdoc in CNR-INO (National Institute of Optics), Italy. He received his PhD from Peking University in 2021. His research interests cover laser plasma physics, laser-driven ion acceleration, advanced target fabrication, diagnosis of ion beams and plasmas, high energy density physics (HEDP).

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報告人：鄭振亞，中國科學院上海天文臺

時間：7月2日（週二）16:00

單位：中國科學技術大學 - 天文學系

鏈接：

摘要：

當前正在運行和建造的先進望遠鏡如HST、JWST、CSST等正在幫助我們逐步揭開早期宇宙的神秘面紗。它涉及宇宙中早期天體，即恆星、星系和黑洞的誕生和演化，及其所產生的電離光子重新電離整個宇宙中的中性氫環境，該過程又被稱爲宇宙再電離。報告將基於針對早期宇宙星系的發射線星系巡天，包括LAGER和CIDER巡天、HST窄帶深場HDHα項目，以及JWST/HST等深場和紫外觀測，從觀測上介紹對宇宙再電離的電離歷史、物理過程和此時期天體演化的相關研究。報告重點介紹：（1）基於LAGER和CIDER等巡天的紅移7附近的宇宙再電離歷史研究；（2）基於HST和CSST等觀測的再電離過程中電離光子逃逸問題研究；（3）基於JWST和LAMOST/SDSS等巡天的再電離時期星系和原初星系團及其近鄰對應體的研究。

報告人簡介：

鄭振亞，中科院上海天文臺研究員，“早期宇宙與高紅移星系”課題組長，光學天文技術研究室副主任（主持工作），中國科學院特聘研究崗位（核心）。先後在2006年和2012年獲得中國科學技術大學天文學學士和天體物理學博士學位，之後在美國亞利桑那州立大學和智利天主教大學開展博士後研究工作，於2016年入職上海天文臺任研究員至今。目前聯合承擔空間站光學巡天望遠鏡後端多通道成像儀MCI載荷的研製任務（擔任MCI責任科學家），並主持科技部重點研發專項課題。曾主持自然科學基金優青項目和麪上項目、中科院高層次人才青年項目、上海市浦江人才項目。主要研究興趣包括遙遠星系、宇宙再電離以及光學天文前沿觀測技術等。

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報告人：Prof. Tahei Tahara，Molecular Spectroscopy Laboratory，RIKEN

時間：7月3日（週三）15:00

單位：中國科學院物理研究所

地點：M樓236會議室

摘要：

Liquid interfaces provide unique environments where various important chemical/physical processes occur. Heterodyne-detected vibrational sum-frequency generation (HD-VSFG) directly measures the phase and amplitude of the 2nd-order nonlinear optical signal generated only from the interface region of a few monolayer thicknesses. Therefore, time-resolved HD-VSFG provides interface-selective time-resolved vibrational spectra interpreted as the spectral change induced by photoexcitation.

We realized that femtosecond IR-excited and UV-excited time-resolved HD-VSFG were used to observe ultrafast processes directly proceeding at the water interfaces. We recently clarified the vibrational relaxation mechanism of free OH and obtained an overall picture of the vibrational relaxation process of the OH stretch at the air/water interface. Furthermore, we successfully tracked a drastically accelerated photochemical phenol reaction at the water surface. These studies on phenol photochemistry indicated the generality of the significant difference in reaction dynamics between the interface and bulk.

報告人簡介：

Tahei Tahara graduated and obtained his Ph.D. from the University of Tokyo in 1984 and 1989. After being a research associate at the University of Tokyo in 1989 and at Kanagawa Academy of Science and Technology in 1990, he joined the Institute for Molecular Science (IMS) as an associate professor and started his own research group in 1995. He moved to RIKEN as a chief scientist in 2001 and has been the director of the Molecular Spectroscopy Laboratory since then. His research interests are ultrafast spectroscopy, nonlinear spectroscopy, and single-molecule spectroscopy of complex molecular systems.

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報告人：Andrey Sadofyev，LIP，Lisbon

時間：7月4日（週四）15:00

單位：北京大學物理學院

地點：物理學院西B105

騰訊會議: 202-874-142

摘要：

Over the last decades, the theoretical picture of how hadronic jets interact with nuclear matter has been extended to account for the medium's finite longitudinal length and expansion. However, only recently a first-principle approach has been developed that allows to couple the jet evolution to the medium flow and anisotropic structure. In this talk, l will review these developments, and discuss the features of jet quenching in evolving matter. l will consider the modifications of the single particle momentum broadening distribution and single-gluon production rate, and briefly discuss the potential phenomenological implications.

報告人簡介：

Andrey is a theoretical physicist working on the many-body quantum field theory and its applications in the context of QCD matter and systems with ultrarelativistic spectrum. He received his PhD from MIT in 2017, and joined LANL as an Oppenheimer fellow the same year. He moved to University of Santiago de Compostela in 2020, and was awarded a Marie-Curie fellowship in the same year. Currently, Andrey is a junior researcher at LlP Lisbon with a position funded by the Portuguese foundation forscience and technology.

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報告人：魏世傑，北京量子信息科學研究院

時間：7月8日（下週一）10:00

單位：MindSpore Quantum Special Interest Group

鏈接：

摘要：

本報告首先簡要介紹量子計算的背景知識以及量子算法的歷史。隨後介紹量子維度約化算法（QRDR）的基本框架和共振躍遷原理。最後介紹我們展示了我們的算法與兩種量子分類器（量子支持向量機和量子卷積神經網絡）相結合的性能，分別用於對水下探測目標和量子多體相進行分類。使用MindSpore Quantum的模擬結果表明，應用 QRDR 後，數據減少提高了處理效率和準確性。隨着量子機器學習的不斷進步，我們的算法有可能應用於各種計算領域。

圖片來源於：https://physicalsciences.lbl.gov/2023/06/27/jet-substructure-as-a-powerful-probe-of-quantum-chromodynamics-2/

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