理论物理学的十大基本思想、等离子体光学研究若干进展、二维范德华磁体、数据的拓扑结构 | 本周物理讲座

1

报告人：李刚，中山大学

时间：7月15日（周二）10:30

单位：中国科学院理论物理研究所

地点：北楼202

摘要：

Various weak processes at the hadronic scale have been utilized to search for new physics at high energy scale, which can be described by the QCD chiral Lagrangian matched from the low-energy effective theory (LEFT). Utilizing the chiral symmetry SU(2)L×SU(2)R→SU(2)V at the quark and hadronic levels, we make a comprehensive comparison of various matching methods, including the external source method, conventional spurion method, and our systematic spurion method. Although different methods show agreements for dimension-6 LEFT operator matching, we find that for higher-dimensional operators, the external source method is quite limited or inapplicable, the conventional spurion methods needs to introduce more and more spurions, while our spurion method does not need to introduce any new spurions than the ones in the dimension-6 matching. Using minimal set of spurions, we thus establish an one-to-one correspondence between the LEFT and chiral operators, with several examples, such as derivative operators at dimensions 7 and 8 with a single bilinear, four-quark operators at the dimension-9 level with two quark bilinears, which can be applied to the study of neutrino/electron scatterings and neutrinoless double beta decay.

报告人简介：

李刚，中山大学物理与天文学院副教授。2017年博士毕业于北京大学，先后在台湾大学和马萨诸塞大学阿默斯特分校做博士后。主要研究方向为超出标准模型的新物理，目前集中在中微子相关的新物理唯象研究。

2

报告人：Dr. Antonio Ortiz-Ambriz，Tecnologico de Monterrey

时间：7月15日（周二）15:00

单位：中国科学院物理研究所

地点：M楼253会议室

摘要：

Artificial Colloidal Ice is a model system for geometric frustration,which has the advantage that its dynamics are accessible on experimental time and length scales. It consists of magnetic colloids placed inside bistable potentials,realized by lithographically etching grooves into a substrate. The superparamagnetic colloids can be made to interact by applying an external magnetic field,usually perpendicular to the surface,which makes them repulsive.

Using numerical simulations, we find that if the rotational symmetryof the interactions is broken by tilting the field, the system presents many interesting phenomena. When quenching at finite times, the particles freeze in disordered configurations, even in the absence of quenched disorder in the underlying substrate. On the other hand, when starting from an ordered state with repulsiveinteractions, the rotation of the field induces a diffusionless, martensite-like transformation, which interestingly, falls into ordered states only at fast transition rates, but becomes disordered if the transition is carried out slowly enough.

报告人简介：

Antonio Ortiz-Ambriz did his Ph. D. in optics at Tecnológico de Monterrey,where he specialized in optical tweezers. He then went to work as a postdoctoral researcher at the University of Barcelona with Prof. Pietro Tierno. During this time,he worked in colloidal model systems of non-equilibrium statistical physics,combining magnetic colloids,optical tweezers,microlithography,and numerical simulations. Currently,he is a research professor in the science department at Tecnologico de Monterrey.

3

报告人：Prof. Ilya M. Eremin，Ruhr-University Bochum, Germany

时间：7月16日（周三）10:00

单位：中国科学院物理研究所

地点：M236会议室

摘要：

Recently discovered high-Tc superconductivity in pressurized bilayer nickelate bulk crystals La3Ni2O7 (La-327) and their thin films under compressive strain are believed to be driven by the non-phononic repulsive interaction. Depending on the strength of the interlayer repulsion, the symmetry of the superconducting order parameter is expected to be either d-wave or sign-changing bonding-antibonding s±-wave order parameter, respectively. In my presentation I will analyze the peculiar features of the electronic structure of these systems and the interplay of multiple orbitals in the normal and the superconducting states. Discussing various superconducting states we show that the bilayer structure of the spin response allows to elucidate the role of the interlayer interaction and the nature of the Cooper-pairing in a very efficient way. We further analyze the sensitivity of the obtained results with respect to the potential electronic structure modification and applied pressure.

报告人简介：

Ilya M. Eremin graduated from Kazan State University in 1996 and received his Ph.D. degree in Physics from the Kazan State University in 1999. He was an Alexander von Humboldt Research fellow at the Free University of Berlin, and become a Junior-Professor (2005-2010) at the Max-Planck Institute of Physics of Complex Systems, a University Professor (2010-2019) and then a Chair Professor (2020-present) at the Ruhr-University Bochum, Germany. His interests lie in general field of quantum many-body theory and its application in condensed matter with confined geometries and related systems, mostly focusing on the strongly correlated electron systems and unconventional superconductors.

4

报告人：徐一鸿/Anthony Zee，Kavli Institute for Theoretical Physics and Department of Physics, University of California, Santa Barbara

时间：7月16日（周三）10:00

单位：中国科学院理论物理研究所

地点：北楼322

5

报告人：Gary Shiu，University of Wisconsin, Madison

时间：7月17日（周四）15:00

单位：中国科学院理论物理研究所

地点：南楼6620

Zoom Meeting ID: 831 7825 2762

Passcode: 957920

6

报告人：盛政明，上海交通大学

时间：7月17日（周四）20:00

单位：中国科学院理论物理研究所

腾讯会议: 105-819-247

密码: 654321

7

报告人：王华嘉，中国科学院大学/KITS

时间：7月18日（周五）9:00

单位：中国科学院理论物理研究所

地点：北楼322

摘要：

When a local QFT is coupled to gravity, properties of its energy (or more generally the stress tensor) density expectation values play a crucial role in the gravitational dynamics. Classical conjectures of the stress tensor density (known as the energy conditions) are easily violated in QFTs. Conjectures about the quantum versions of the energy conditions (e.g. ANEC, QNEC) were proposed. Much progresses have been made in the recent decade for understanding and proving these quantum energy conditions. Their origins were found surprisingly in the universal properties of the entanglement structures of the QFTs. In this lecture series, I will review the developments related to the quantum energy conditions, emphasizing on the recent progresses of entanglement-based proofs.

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报告人：Mikhail Shaposhnikov，EPFL, Switzerland

时间：7月18日（周五）15:00

单位：中国科学院理论物理所

地点：南楼6620

Zoom Meeting ID: 852 8931 7685

Passcode: 649651

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