磁场精密测量、浅谈工程物理、高曲率引力、奇异金属、工程物理 | 本周物理讲座

1

报告人：齐志，北京大学

时间：6月10日（周二）16:00

单位：中国科学院理论物理研究所

地点：北楼202

2

报告人：王凯，浙江大学

时间：6月11日（周三）15:00

单位：中国科学院理论物理研究所

地点：北楼CCAST五楼报告厅

摘要：

工程是一个围绕确定目标通过有组织活动实现人造产品的过程，而物理作为最典型的自然科学，以探索人类未知为驱动，研究物质一般运动规律和基本结构。从1938年底核裂变现象的发现到1942年核反应堆实现临界和1945年原子弹爆炸成功，人类科学史上第一次在如此短的时间内实现了从基础科学到工程应用的转变，展现了一个典型的工程科学的路径。报告将从核物理的发展，介绍核反应堆到原子弹、氢弹的基本物理原理和发展历史。特别是我国一批从事基础物理学研究的科学家，转行进入核武器这个当年的“卡脖子”领域，从源头和底层出发，快速突破实现了跨越式发展，不仅快速实现了原子弹，还比现代核物理发祥地法国早一年实现了氢弹的突破。我国的核武器发展历史说明不能将核武器简单地视为工程技术问题，而要当成科学问题来展开研究，知其然知其所以然，进一步展现了工程物理的研究路径。

报告人简介：

王 凯，浙江大学物理学院教授，中国核学会辐射物理分会常务理事《中国科学-物理力学天文》编委，长期从事理论物理研究，特别是粒子物理理论和高能量密度物理理论，主编教育部101计划教材《近代物理导论》。

3

报告人：Long-Qing Chen，The Pennsylvania State University, USA

时间：6月12日（周四）9:00

单位：Microstructures期刊

链接：

报告人简介：

Long-Qing Chen is Hamer Professor of Materials Science and Engineering at Penn State. He received his Ph.D. from MIT, M.S. from Stony Brook University, and B.S. from Zhejiang University. His main research interests include thermodynamic theory and computational model development for understanding solid phase transitions and microstructure development. His research awards include the Materials Research Society (MRS) Materials Theory Award, The Minerals, Metals & Materials Society (TMS) John Bardeen Award, American Ceramic Society (ACerS) Ross Coffin Purdy Award, TMS Cyril Stanley Smith Award, TMS William Hume-Rothery Award, The American Society of Metals (ASM) International Silver Medal, and IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society (IEEE-UFFC-S) Distinguished Lecture Award. He is a Guggenheim Fellow, a Humboldt Research Awardee, a Foreign Member of Academy of Europe (Academia of Europaea, MAE), and a member of the US National Academy of Engineering (NAE).

4

报告人：Sudipta Sarkar，IIT Gandhinagar, India

时间：6月12日（周四）10:30

单位：中国科学院理论物理研究所

地点：北楼322

Zoom Meeting ID: 893 2377 7487

Passcode: 524849

摘要：

The Einstein-Hilbert action represents the simplest generally covariant formulation of gravity. Despite the success of Einstein' s field equations across a wide range of scales, theoretical motivations, including insights from quantum gravity, string theory, and effective field theory suggest that the classical theory may be incomplete. These considerations naturally lead to the inclusion of higher curvature invariants as corrections to the Einstein-Hilbert action. In this seminar, I will provide an overview of the rationale behind such modifications and examine their physical implications. Particular emphasis will be placed on the challenges posed by higher curvature terms, including potential violations of causality and issues of classical and quantum stability. The goal is to assess the viability of these extended theories and their prospects for providing a consistent extension of general relativity.

报告人简介：

Sudipta Sarkar is a Professor of Physics at the Indian Institute of Technology (IIT) Gandhinagar, India. He obtained his Ph.D. from the Inter-University Centre for Astronomy and Astrophysics (IUCAA), Pune, and subsequently conducted postdoctoral research at the University of Maryland, USA. His research interests lie primarily in gravitation, gravitational waves, and black hole physics. He is visiting the Institute of Theoretical Physics as a Peng Huanwu Visiting Professor.

5

报告人：张啸天，中国科学院大学卡弗里理论科学研究所

时间：6月12日（周四）14:00

单位：中国科学院物理研究所

地点：怀柔园区X1南楼101会议室

腾讯会议：226-676-255

会议密码：2025

摘要：

Strange metals are ubiquitously observed in a variety of strongly correlated materials, among which high temperature cuprates, ruthenate oxides, and twisted bilayer graphene are the most prominent examples. In these materials, the critical quantum fluctuations are often accompanied by the Lifshitz transition of the Fermi surface where the Fermi surface exhibits van Hove singularity (VHS) and its geometry changes from convex to concave. In this talk, we address the nature of such an extreme correlated matter when both the VHS and wild quantum critical fluctuations are entangled. We adopt the Yukawa-SYK model with a spatially uniform Yukawa interaction and self-consistently solve for the low-energy effect theory which yields non-Fermi liquid states at distinct energy scales. Furthermore, we clarify the electron scattering mechanism at the Lifshitz transition and evaluate the optical conductivity and dc-resistivity by means of diagrammatic expansion. We demonstrate a linear-in-ω optical conductivity at T=0 and, more importantly, the strange metal behavior with a linear-in-T dc-resistivity in the entire quantum critical regime extending down to T→0. At higher temperatures, it eventually gives in to a non-universal scaling. In addition, we also consider the spatially random Yukawa interaction which gives rise to linear-in-T resistivity extending even into the non-universal high-T regime. Finally, we argue that our theoretical scheme for the strange metal is free from the severe short-circuit issue.

If time allows, we will briefly mention another line of development which forges an emerging interdisciplinary field between spintronics and strongly correlated matters. To set an example, we study the spin pumping effect without well-defined quasiparticles.

报告人简介：

Xiao-Tian Zhang earned his bachelor’s degree from the College for Gifted Youngs at the University of Science and Technology of China in 2013. He then pursued his PhD at the International Center for Quantum Materials, Peking University, under the supervision of Prof. Ryuichi Shindou, graduating in 2019. From 2019 to 2022, he worked as a postdoc in Prof. Gang Chen’s group at the University of Hong Kong. In 2022, he joined the Kavli Institute for Theoretical Sciences as a Postdoctoral Fellow in collaboration with Prof. Fu-Chun Zhang and Special Research Assistant of UCAS (a.k.a. Assistant Researcher).

6

报告人：Zhiyu Zhang，NJU

时间：6月12日（周四）15:30

单位：北京大学物理学院

地点： KIAA-auditorium

摘要：

Elemental abundance and their ratios along the Galactocentric radius provide key information about the chemical evolution of the Milky Way. The 12C/13C ratio, in particular, is widely adopted as a proxy to infer other isotopic ratios, such as 16O/18O and 14N/15N. Traditionally, emission lines of 12CN and 13CN – with their optical depths corrected based on their hyper-fine structure lines – have traditionally been exploited to measure 12C/13C isotopic ratios. However, such a method has major pitfalls, with oversimplified (and overlooked) assumptions in both theory and observational interpretations. The optically-thin satellite-lines of 12CN and 13CN transitions present the advantages over the 'classical method', but still suffers bias from non-trivial effects from non-Local Thermal Equilibrium conditions. Our new measurements of 13C18O and C18O emission lines provide a promising new avenue for isotopic ratio determinations. With it, we further obtained the virial states of low-metallicity molecular clouds in the outer Galactic disk. Our analysis shows that the turbulent kinetic energy cannot support self-gravitational energy in these clouds, suggesting that the magnetic field likely play a dominant role in supporting clouds in such conditions.

报告人简介：

Zhiyu Zhang is a faculty member at the School of Astronomy and Space Science, Nanjing University, specializing in observational radio astronomy. His research interests include the multiphase interstellar medium, astrochemistry, the stellar initial mass function, and the chemical evolution of galaxies. He earned his Master's and PhD degrees from Purple Mountain Observatory, with part of his doctoral research conducted at the Max Planck Institute for Radio Astronomy in Germany. From 2014, he held postdoctoral positions at the University of Edinburgh and the European Southern Observatory. He has been serving as a professor at Nanjing University since 2019.

7

报告人：李昺，中国科学院金属研究所

时间：6月13日（周五）15:00

单位：中国科学院理论物理研究所

地点：北楼202

8

报告人：李强，北京大学

时间：6月13日（周五）15:40

单位：中国科大离子科学与技术研究中心、基本粒子和相互作用协同创新中心、核探测与核电子学国家重点实验室

链接：

摘要：

Scientists from the Chinese LHC ATLAS and CMS groups have made substantial contributions to the construction, operation/maintenance and upgrade of the ATLAS/CMS detector, as well as in Higgs boson discovery, SM tests and BSM searches. Our projects in next years include continuing exploring physics of the electroweak symmetry breaking, precision test of the SM, and searching for possible BSM. These projects are crucial goals of the LHC experiment. We plan also to extend our scope to cover novel topics, such as 2 to 3 Vector boson scattering, advanced jet tagging for boosted bosons, and Quantum entanglement studies with bosons, etc. In addition, by interfacing CMS’s muon detectors with muon beams or cosmic rays, we propose here a set of new methods involving probing and knocking with muons (PKMu). There is a wealth of rich physics to explore, for example, 1‒10 GeV muons scattering off electrons in target materials have a center-of-mass energy near 10 MeV, which makes them highly sensitive to dark bosons in the MeV mass range.

报告人简介：

李强，北京大学物理学院博雅特聘教授，技术物理系副系主任，2023年国家杰出青年基金获得者。长期致力于大型强子对撞机CMS实验上的多玻色子物理研究，在多玻色子物理研究领域取得一批重要进展，包括通过多玻色子探针对标准模型精确测量、挖掘稀有标准模型过程以及利用人工智能方法鉴别玻色子喷注并应用于多玻色子共振态寻找等。近年来也致力于未来对撞机和缪子打靶实验的软件和物理研究，获得2021年度基金委原创探索基金项目支持。先后担任CMS物理产生子组及计算软件组二级召集人，自2023年起担任CMS合作委员会顾问委员、School委员会委员。受邀在轻子光子会议、ICFA seminar等国际会议作大会报告介绍电弱物理，担任ICHEP2024会议电弱及顶夸克分会召集人。指导的博士生肖杰、李聪乔先后获得中国物理学会高能物理分会第十二届和第十三届“晨光杯”青年优秀论文一等奖。

9

报告人：唐原江，清华大学

时间：6月16日（下周一）10:00

单位：中国科学院物理研究所

地点：北楼CCAST五楼报告厅

摘要：
磁场精密测量是精密测量领域的重要发展方向，其中基于热原子系综的原子磁力计已经成为最灵敏的磁场探测器之一，广泛应用于生物医学和前沿物理研究等领域。本报告将介绍在热原子系综中引入反馈调控手段，构造宇称-时间(PT)对称系统和非线性相互作用系统，并利用其特性研究磁场精密测量的新方法。同时还将介绍在热原子非线性系统探索过程中发现的时间晶体现象，以及我们提出并验证的时间晶体产生机制。

报告人简介：
唐原江博士分别于2019年获得复旦大学学士学位，2024年获得清华大学博士学位，现为清华大学物理系博士后，合作导师为尤力教授。博士期间主要从事基于热原子系综的量子精密测量，至今已在物理学重要期刊发表论文8篇(其中PRL文章3篇)，目前研究兴趣为里德堡原子阵列研究。2024年至今，主持中国博士后创新人才支持计划。

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