量子自旋液体、统计热力学可积性、引力波波动性、核子晶格有效场论 | 本周物理讲座

我们如何理解宇宙？ | 科学公开课‍

1

报告人：孙昌璞，中国工程物理研究院

时间：9月14日（周六）14:00

单位：中国科学院理论物理研究所

地点：北楼322

摘要：

基于热力学第二定律的卡拉西奥多里原理，引入量子热力学可积性(QTI)的概念，为统计力学提供了个现代基础。在这一框架下，温度作为一个积分因子， 伴随着热力学熵衍生出来。从而基于 QTI熵可积方程(EIE)，不仅可以推导出正则热平衡态， 而且得到了偏离热平衡的非正则态，从而揭示了有限尺寸热力学系统和有限时间过程中信息相关性的存在，如黑洞等小系统的辐射关联及其信息丢失现象。有限时间热循环过程的标志是熵产生，它导致的功率-效率约束关系， 对此我们不仅进行了系统性的实验检验，而且建立了其最优调控的黎曼几何方法。这些工作代表了我们过去二十年对统计热力学从基础到应用、从经典到量子、从平衡到非平衡的研究探索的系列性成果。

报告人简介：

孙昌璞，理论物理学家，中国科学院院士，发展中国家科学院院士，中国工程物理研究院研究生院创院院长、北京计算科学研究中心讲座教授。本科毕业于东北师大物理系，于南开大学获博士学位。曾任东北师大教授，中科院理论所研究员。获得过国家自然科学二等奖和美国1S!“经典引文奖”等奖励以及全国先进工作者等荣誉称号。他长期组织参与我国物理学科战略规划工作(基金委和科学院十三五发展规划的秘书组组长和十四五规划的战略组组长)，是中国物理学会副理事长，国家自然科学基金委员会监督委员会副主任，并担任中国科学院哲学研究所学术委员会主任、北京大学物理学科卓越人才培养指导委员会主任。

他长期从事量子物理、数学物理、量子信息基础理论的研究，其原创性的研究工作有重要国际影响。目前工作集中在复杂体系统计热力学、能源物理和长贮装备系统可靠性理论的研究，开展了面向国家需求的科技发展战略研究和模式创新探索。目前他主持国家自然科学基金委员会的基础中心项目《基础能源物理的科学问题》。他重视青年人才的培养，连续讲授高等量子力学大课多年，著有《经典杨-米尔斯场理论》和《量子力学现代教程》。他10次被评为中科院“优秀导师”，指导的研究生有2人获全国“百篇优秀博士学位论文”、10余人获得“中国科学院优秀博士论文”和中国科学院院长特别奖等。他也是人教社中学物理教材的总顾问和前言的撰写者。

2

报告人：Prof. Dr. Ulf-G. Meißner，Bonn University/Forschungszentrum Jülich

时间：9月10日（周二）15:00

单位：清华大学物理系

地点：物理楼W361

摘要：

Neutrinoless double-beta decay is one of the most interesting nuclear reactions. In this talk, I introduce Nuclear Lattice Effective Field Theory as a new tool in nuclear theory. It allows to address nuclear structure and reactions simultaneously. I show assorted results obtained so far. In particular, I will address the recent work on triton beta-decay, which is an important first step in addressing neutrinoless double-beta decay in this framework.

报告人简介：

Prof. Dr. Ulf-G. Meißner is a full professor in theoretical physics and the leader of the theory group of the Helmholtz Institute for Radiation and Nuclear Physics at Bonn University. He is a renowned strong interaction physicist. Being the leader of a world-leading team on theoretical nuclear and hadron physics, he is the director of the Institute for Nuclear Physics-3 (IKP-3) and director of the Institute for Advanced Simulation-4 (IAS-4) at the Jülich Research Center. He was the dean of the Faculty of Natural Sciences and Mathematics, Bonn University, from 2008 to 2016. Here are a few among the many awards and honors he received: ERC Advanced Grant (2021), CAS President’s Fellowship for Distinguished Scientists (2018), Lise-Meitner Prize of the European Physical Society (2016), member of Academia Europaea (2010), Fellow of the American Physical Society (2009). He is also the Spokesperson of the Sino-German Collaborative Research Center CRC110. He has published more than 700 papers with a total citation of more than 77000 and an h-index of 115.

3

报告人：同宁华，中国人民大学物理系

时间：9月11日（周三）10:00

单位：中国科学院物理研究所

地点：M830

摘要：

The projective truncation approximation (PTA) is a systematic and well-controlled method for solving the equation of motion of two-time Green's functions for many-body system. It has advantages over the conventional Tyablicov truncation sheme due to the projection idea. In this talk, I will report recent progress in the developement of PTA, including (1) H-expanded basis for describing thermal decay of particles, and (2) composite basis for describing quasi-particle interaction and collective excitation.

报告人简介：

1997年毕业于复旦大学材料科学系；2002年在中国科学院物理研究所获得理学博士学位；2002-2005在德国奥格斯堡、科尔斯鲁厄大学做洪堡学者和博士后研究工作。2006至今在中国人民大学物理系任教。主要研究包括莫特相变、杂质量子相变等量子多体物理体系，着重发展量子多体数值方法，包括动力学平均场理论、数值重整化群、格林函数运动方程等。已发表学术论文50余篇。

4

报告人：Yi Zhou，Institute of Physics, Chinese Academy of Sciences

时间：9月11日（周三）15:00

单位：北京大学物理学院

地点：西563会议室

摘要：

In this talk I will present our efforts to go beyond the "standard" model of the quantum spin liquid, which was formulated as a gauge theory. The new formulation is a Landau-type effective theory. Both quasiparticle-like excitations and collective modes will be discussed, as well as their physical consequences.

报告人简介：

Yi Zhou is a professor at Institute of Physics, Chinese Academy of Sciences. He received his B.S. degree and Ph. D. in physics from Tsinghua University in 1998 and 2004 respectively. After postdoctoral journey, he became a faculty member in Zhejiang University in 2009 and moved to current position in 2019. His main research interests include quantum many-particle physics and theoretical condensed matter physics.

5

报告人：Chen Yang，Scuola Normale Superiore

时间：9月12日（周四）13:30

单位：清华大学物理系

地点：物理楼W105

摘要：

I will discuss primordial universe scenarios where the inflaton is weakly coupled to a strongly-self-interacting theory, and study the imprints in cosmological correlators. There are three general scenarios for the strongly coupled sector based on its mass gap in Hubble units. I will focus on the gapless scenario, which I fully solved, and will discuss two approaches to computing its correlators: the Cosmological Bootstrap and Mellin-Barnes integration. Finally, I will compare the signals to weakly coupled scenarios and comment on the potential to distinguish them.

报告人简介：

I’m currently a PhD student in the theoretical high-energy physics group at Scuola Normale. Previously I graduated from Fudan University in 2020 and obtained my master’s degree from the University of Amsterdam in 2022. My current research interest lies in de Sitter physics with possible applications of holography, in both mathematical and phenomenological aspects.

6

报告人：孙志远，清华大学

时间：9月12日（周四）15:00

单位：中国科学院物理研究所

地点：M楼236会议室

腾讯视频会议号：397-806-937，密码：240912

摘要：

The ponderomotive force is an effective static force that a particle feels in an oscillating field, whose static potential may be called the ponderomotive potential. We generalize this notion to periodically driven quantum many-body systems, and propose it as a convenient tool to engineer their non-equilibrium steady states beyond the single particle level. Applied to materials driven by light, the ponderomotive potential is intimately related to the equilibrium optical conductivity, which is enhanced close to resonances. We show that the ponderomotive potential from the incident light may be used to induce exciton condensates in semiconductors, to generate attractive interactions leading to superconductivity in certain electron-phonon systems, and to create additional free energy minima in systems with charge/spin/excitonic orders. These effects are presented with experimentally relevant parameters.

报告人简介：

Zhiyuan Sun obtained his BS in 2012 from University of Science and Technology of China, and his PhD in 2018 from UC San Diego. He worked as a postdoctoral/associate research scientist at Columbia University during 2018~2021, and as an HQI postdoc Fellow at Harvard University during 2021~2022. Since 2022, he has been an assistant professor at the physics department of Tsinghua University. Zhiyuan works on condensed matter theory, specifically, nonequilibrium phenomena in many-body systems, light-matter interactions, and nano-optics.

7

报告人：邢志忠，中国科学院高能物理研究所

时间：9月12日（周四）15:00

单位：中国科学院理论物理研究所

地点：北楼322

摘要：

Tiny neutrino masses and large lepton flavor mixing angles areexpected to originate from new physics bevond the standard mode(SM) of particle physics, but which kind of new physies is mostlikely has been an open question. This talk is intended to highlightthe canonical seesaw mechanism as a favorite, given the lessonlearnt from historical roles that lepton fayors haye plaved in thedevelopment of the SM. Some personal opinions are added on painsand gains in introducing new degrees of freedom.

报告人简介：

邢志忠，中国科学院高能物理研究所研究员。1987年毕业于北京大学物理系，1993年获得高能所博士学位，之后在慕尼黑大学和名古屋大学从事博士后研究，2001年入职高能所，主要研究领域为中微子物理学。

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报告人：岩斌，IHEP, CAS

时间：9月12日（周四）15:00

单位：北京大学物理学院

地点：物理学院西B105

摘要：

The absence of signals for new heavy resonances at the Large Hadron Collider (LHC) suggests that the scale of new physics(NP) likely significantly exceeds the electroweak scale. The Standard Model Effective Field Theory(SMEFT) has become avaluable framework for systematically capturing potential NP effects, with leading contributions expected from dim-6 operators. However, chirality-flipping dim-6 operators for light fermions，which are poorly constrained as their interference with the SM will be highly suppressed. In this talk, l will discuss recent progress in exploring these NP effects through transverse polarization effects without such suppression, and it also offering a new avenue to investigate potential CP violation effects.

报告人简介：

岩斌，2012年毕业于重庆大学物理学院，2017年获得北京大学物理学院博士学位。2017年至2019年在美国密歇根州立大学做博士后研究员，2019年至2022年在美国洛斯阿拉莫斯国家实验室担任博士后研究员，并获得 Director's Postdoctoral Fellow。2022年6月进入中国科学院高能物理研究所任副研究员，2024年获国家自然科学基金委优青项目支持。研究方向为 TeV 物理唯象学，具体包括希格斯和顶夸克物理，标准模型有效场论，对撞机物理等。

9

报告人：Jianhua He，南京大学

时间：9月12日（周四）15:30

单位：北京大学物理学院

地点：KIAA-Auditorium

摘要：

Wave effects are a crucial aspect of gravitational waves. When the wavelength of GWs is comparable to or greater than the Schwarzschild radius of an object, the propagation of gravitational waves no longer follows geometrical optics, and coherence and interference can occur. Despite their significance, studying these wave effects can be challenging due to their complexity.

In this talk, I will discuss numerical techniques for simulating these effects in the gravitational field of a Schwarzschild black hole. I will talk about the back-scattering effect of the interaction between GWs and the background curvature. Finally, I will discuss the potential detectability of these wave effects in aLIGO.

报告人简介：

He Jianhua is a professor at the School of Astronomy and Space Science, Nanjing University. In 2006, he received his Bachelor's degree in Physics from Shanghai Jiao Tong University. In 2011, he got his PhD in Theoretical Physics from Fudan University. From 2011 to 2015, he conducted postdoctoral research at the INAF in Italy. From 2015 to 2018, he was awarded the International Junior Research Fellowship by Durham University in the UK and worked at the Institute for Computational Cosmology (ICC, Durham) on research projects. In December 2018, he joined the School of Astronomy and Space Science of Nanjing University. His research areas include modified gravity, cosmic microwave background radiation, numerical simulations of large-scale structure formation in the universe, and observations of large-scale galaxy surveys. Currently, he is primarily engaged in research related to gravitational waves, numerical relativity, and experimental detection of dark energy. So far, he has published one paper in Nature Physics, one in Nature Astronomy (cover of the December 2018 issue), and three in Phys. Rev. Lett. as the first/corresponding author.

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报告人：何颂, 中科院理论物理研究所

时间：9月12日（周四）16:00

单位：清华大学物理系

地点：理学院郑裕彤大讲堂

摘要：

I will give an overview of the recent progress in computing and especially understanding scattering amplitudes and related quantities (such as correlation functions) in Quantum Field Theory, gravity and string theory, including all-loop geometries underlying amplitudes and correlators in maximally supersymmetric Yang-Mills theory, as well as the discovery of a combinatorial, string-like formulation for real-world scattering of colored scalars, pions and gluons.

报告人简介：

何颂，中科院理论物理研究所研究员。长期活跃在量子场论、量子引力和弦论等高能理论前沿，近年来主要工作集中在场论、引力和弦论中的散射振幅等物理量，及其对粒子物理、引力和宇宙学乃至数学方向的应用。近年来代表性工作包括被称为Cachazo-何-袁体系的散射振幅新理论，与N. Arkani-Hamed合作建立的场论和弦论散射的几何描述，以及在规范场、引力和弦论内在联系、量子场论和全息对偶的精确计算、数学物理等方向取得的一系列进展。

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