1

報告人：Jianda Wu，Shanghai Tsung-Dao Lee Center

時間：2月25日（周二）13:30

單位：清華大學物理系

地點：物理樓W105

摘要：

Exotic thermodynamics and excitations can emerge in the vicinity of a quantum phase transition. In the talk, I will first detailedly discuss the unique quantum criticality for the Grüneisen ratio in the transverse field Ising chain (TFIC). The unique quantum criticality of the Grüneisen ratio then serves as a smoking gun to identify the underlying TFIC universality observed in quasi-1D antiferromagnetic materials BaCo2V2O8 with transverse field applied along [110] direction. From systematic quantum critical analysis for the effective model of the material SrCo2V2O8, we confirm the material with field applied along [100] direction can also accommodate the TFIC universality with much weaker magnetic field. Furthermore, when the quantum critical point of the TFIC is perturbed by a longitudinal magnetic field, it was predicted that its massive excitations are precisely described by the exceptional E8 Lie algebra. Here we first discuss non-trivial low temperature local spin dynamics of the exotic E8 model. Then we show an unambiguous experimental realization of the E8 physics in the material BaCo2V2O8, via nuclear magnetic resonance and inelastic neutron scattering measurements, and detailed theoretical analysis. The large separation between the masked 1D and 3D quantum critical points of the system allows us to identify, for the first time, the full 8 single-particle E8 excitations, various multi-E8-particle states as well as the dispersion of E8 particles in the spin excitation spectrum. Our results open new experimental and theoretical routes for exploring the dynamics of quantum integrable systems and physics beyond integrability, and thus bridge key physics in condensed matter and statistical field theory.

2

報告人：栗建興，西安交通大學

時間：2月26日（周三）10：00

單位：中國科學院理論物理物理所

騰訊會議: 131-383-629
密碼: 654321

摘要：

利用超強超短激光脈沖與等離子體相互作用，強場量子電動力學(QED)效應會起關鍵作用，可以產(chǎn)生強流、超快、具有內(nèi)稟角動量的伽馬光子、正負電子等輻射源，在高能量密度物理、高能粒子物理核物理、核天體物理、實驗室天體物理、材料物理等領域具有廣泛應用價值。目前，強激光驅動輻射源的強流、超快等特性研究已經(jīng)得到了長足發(fā)展，然而，其角動量產(chǎn)生原理與方法等關鍵基礎研究依然較為缺乏?；诖?，本報告將簡要介紹我們課題組在“大角動量伽馬光子、正負電子等輻射源產(chǎn)生原理及其核反應”等研究方向取得的階段性進展。

報告人簡介：

栗建興，西安交通大學教授、博導，國家自然科學基金委杰青、優(yōu)青項目獲得者，陜西省高層次人才，中國原子能院核物理所客座研究員、強脈沖輻射環(huán)境模擬與效應全國重點實驗室客座研究員。主要研究領域包括強場物理、高能量密度物理、激光核物理等。以第一/通訊作者發(fā)表學術論文60余篇，包括PRL10篇。近5年，在本領域重要學術會議作大會報告/邀請報告40余次，并多次承辦/協(xié)辦本領域學術會議。

3

報告人：Jianda Wu，Shanghai Tsung-Dao Lee Center

時間：2月26日（周三）16:00

單位：清華大學物理系

地點：物理樓W105

摘要：

When two quantum critical transverse-field Ising chains (TFIC) are weakly coupled, the weak inter-chain coupling can drive the system to emerge as an integrable model with eight particles, organized by the D8(1) Lie algebra . Realizing the quantum criticality of the TFIC is a key step to access the exotic integrable system. In my talk, after first exposing the quantum criticality of the TFIC, I will begin my journey with an inelastic neutron scattering experiment on CoNb2O6, which claims observation of evidence of E8 physics in the material. Despite a ten-year gap, recent THz spectroscopy on the same material reignited our interest, leading us to challenge the E8 paradigm and propose the D8(1) picture. I will discuss why the D8(1) physics provides a comprehensive understanding for the experimental observations. Along the course, we also surprisingly found long-life-time dark particle, a special kind of many-body magnetic excitation, in the integrable system which accommodates the D8(1) physics. We will discuss how the dark particles are able to be prepared via another exotic soliton excitations in the system, and further propose a thermal activation detection of the lightest dark particle.

4

報告人：肖煌煜，University of Chicago

時間：2月27日（周四）13:30

單位：清華大學物理系

地點：物理樓（附中南側）W260

摘要：

Monopoles are generally expected in Grand Unified Theories (GUTs) where they can catalyze baryon decay at an unsuppressed rate by the Callan-Rubakov effect. For the first time, we show this catalysis effect can generate the observed baryon asymmetry at GeV scale temperatures. We study the minimal SU(5) GUT model and demonstrate that monopoles-fermion scattering with a CP-violating theta-term leads to realistic baryogenesis even theta is as small as 10^-10, consistent with current experimental bounds. Our calculation also shows that to generate the observed baryon asymmetry, the abundance of the monopoles is below the current experiential bounds and becomes an interesting target to look for.

報告人簡介：

Huangyu Xiao received his PhD from the University of Washington in 2022, and is now an associate fellow at the Kavli Institute of Cosmological Physics at the University of Chicago. He works on the intersection of particle physics, cosmology, and astrophysics. His major focus is on the particle nature of dark matter and how to look for it using astrophysical observations. He also works on various ideas on baryogenesis and gravitational waves.

5

報告人：于偉強，中國人民大學

時間：2月27日（周四）15：00

單位：北京大學物理學院

地點：物理樓西202報告廳

摘要：

強關聯(lián)電子體系中的零溫量子相變及其臨界現(xiàn)象一直是凝聚態(tài)物理的前沿研究方向之一。在低維和阻挫量子磁性材料中，強量子漲落、物態(tài)競爭使得量子臨界點附近涌現(xiàn)尤為豐富的新現(xiàn)象。我們開發(fā)了具有高壓、強磁場、極低溫等國際領先聯(lián)合極端條件的核磁共振譜學技術，對低維量子磁性材料進行調控和測試，發(fā)現(xiàn)了量子臨界點附近演生的多種新奇物態(tài)和新型元激發(fā)，其中包括E8代數(shù)態(tài)粒子、雙磁振子凝聚，以及超越朗道理論范式的解禁閉量子臨界、候選量子自旋液體態(tài)等。這些新物態(tài)和新粒子有可能促進對高溫超導機理的理解和量子器件的應用研究。

報告人簡介：

于偉強，2008年起任職中國人民大學物理學院教授。專長高壓、強磁場和極低溫等聯(lián)合調控下的核磁共振譜學測試，研究強關聯(lián)體系中的新奇物態(tài)和元激發(fā)。近年來專注低維量子磁性材料的物態(tài)調控研究，聚焦其中的量子自旋液體、量子相變與臨界現(xiàn)象等。已發(fā)表80余篇學術論文，其中包括Science 1篇，Nature子刊2篇，PRL/PRX 13篇。先后獲得國家自然科學基金委優(yōu)青項目和科技部科技創(chuàng)新領軍人才項目支持，為國家重點研發(fā)項目首席科學家、基金委重點項目主持人。

6

報告人：Dario Vretenar，University of Zagreb, Croatia

時間：2月27日（周四）15:30

單位：中國科學院理論物理研究所

地點：北樓202

摘要：

Nuclear fission presents an example of large-amplitude collective motion in self-bound mesoscopic systems that exhibits both classical and quantal features. This process is relevant for the stability of superheavy elements, production of short-lived exotic nuclides far from stability, nuclear astrophysics, and the mechanism of nucleosynthesis. Based on recent developments of time-dependent nuclear density functional theory (TD-DFT) and the time-dependent generator coordinate method (TD-GCM), significant advances in microscopic description of various aspects of induced fission dynamics have been reported. These include studies of the effect of fluctuations on fission observables, dynamics of neck formation and rupture, the energy dissipation mechanism and total kinetic energy distribution, fragment distributions and properties of fragments beyond scission. Finite-temperature effects have been considered in TD-DFT, while the TD-GCM has been generalized to include time-dependent generator states. With the coherent superposition of TD-DFT trajectories in the generalized TD-GCM, fission dynamics is described fully quantum mechanically in an approach that extends beyond the adiabatic approximation and includes quantum fluctuations.

報告人簡介：

Dario Vretenar is professor of theoretical physics at the University of Zagreb and Head of the Nuclear Theory group. He has held postdoctoral and visiting research positions at the University of Bologna, Yale University, Technical University Munich, University of Tokyo, Peking University, and IPN Orsay. Vretenar’s research interests include nuclear energy density functionals, low-energy nuclear effective field theory, nuclear weak interactions and astrophysical applications, algebraic structure models, and fission dynamics. Among his principal contributions is the development of algebraic models for high-spin physics, applications of relativistic energy density functionals to exotic nuclear structure and weak interaction processes, prediction of novel modes of collective excitations in nuclei far from stability, description of quantum shape phase transitions in nuclei, and the development of microscopic models for fission dynamics.

7

報告人：Bin Dong，北京大學

時間：2月27日（周四）15:30

單位：北京大學物理學院

地點：KIAA-auditorium

摘要：

This presentation begins with a brief historical overview, emphasizing instances where AI and mathematics have mutually benefited one another, highlighting their important symbiotic relationship. It then examines significant existing works on AI for mathematics, showcasing their achievements and limitations. Next, the presentation shares preliminary findings from the ongoing AI4M research project at Peking University, including the creation of high-quality mathematical datasets through formalization (digitalization), along with future plans for developing intelligent applications using these datasets. The presentation concludes with a forward-looking perspective on the opportunities and challenges within the interdisciplinary field of AI and mathematics.

報告人簡介：

Professor Bin Dong is a Boya distinguished professor at the Beijing International Center for Mathematical Research and deputy director of the Center for Machine Learning Research. He earned his B.S. from Peking University (2003), his M.S. from the National University of Singapore (2005), and his Ph.D. from UCLA (2009). Following his Ph.D., he completed postdoctoral work at UC San Diego and worked as an assistant professor at the University of Arizona before joining Peking University in 2014. Initially focused on biomedical imaging, Professor Dong developed innovative models using partial differential equations and wavelet theory to address challenges in image reconstruction and segmentation. His early work laid the groundwork for discovering fundamental connections between PDEs and wavelets, advancing image processing techniques in medical applications. More recently, his research has expanded to explore the synergy between artificial intelligence and mathematics, leading to novel deep learning architectures that integrate classical numerical methods with modern data-driven approaches. His contributions have been recognized with awards such as the Qiu Shi Outstanding Young Scholar Award (2014), Wang Xuan Outstanding Young Scholar Award (2023), New Cornerstone Investigator (2023), and an invitation to deliver a 45-minute sectional lecture at the 2022 International Congress of Mathematicians.

8

報告人：Ziqiang Wang, Boston College

時間：2月27日（周四）16:30

單位：清華大學物理系

地點：物理樓（附中南側）W101

摘要：

In ordinary superconductors, an external magnetic field is needed to generate magnetic vortices. We discuss two examples where this conventional folklore breaks down in a fundamental way. The first example is superconductors with strong spin-orbit coupling. We show that topological defect excitations, dubbed quantum anomalous vortices (QAV), can nucleate around magnetic ions spontaneously in the absence of external magnetic fields. When such superconductors possess a Z 2 nontrivial band structure and superconducting topological surface states, as do certain Fe-based superconductors, the magnetic impurity induced QAV are nonabelian and host Majorana zero mode (MZM) in the vortex core. Recent experimental observations of QAV and MZM will be discussed. The second example concerns the newly emerged kagome superconductors AV3Sb5 (A=K, Cs, Rb) that exhibit a cascade of correlated and topological quantum states. We discuss recent experimental evidence for time-reversal symmetry breaking in both the normal and the superconducting state. We argue that the essential phenomenology can be captured by an unconventional charge density wave (CDW) with loop current order. This leads to a Chern metal with a partially filled Chern band and Chern Fermi pockets carrying concentrated Berry curvature. We show how Cooper pairing over the Chern Fermi pockets produces a novel roton superconductor, where the internal phases of three pairing components are locked at 120-degrees and loop supercurrents circulate around an emergent vortex-antivortex lattice with pair density modulations. We discuss extraordinary properties of this chiral topological superconductor and the plausible charge-6e superconductivity in connection to the experimental observation of charge-6e flux quantization.

報告人簡介：

Ziqiang Wang graduated from Tsinghua University in 1984 and received his Ph.D. degree in Physics from Columbia University in 1989. He was a postdoc fellow at Rutgers University and Los Alamos National Laboratory, and became an assistant professor at Boston University in 1993. He is currently a professor in the Physics Department at Boston College. He received a Cottrell Scholar Award in 1996 and a SEED Award in 2021 from Research Corporation for Science Advancement. He is an elected fellow of the American Physical Society.

封面圖片來源：https://www.quantumchina.com/newsinfo/5844570.html

更多報告信息：

《物理》50年精選文章