标准模型中基本粒子的质量问题 I 本周物理学讲座
报告人：罗民兴 院士
时间：6月13日（周三）15:00
单位：中科院物理所
地点：M楼234报告厅
一些基本粒子有质量，一些基本粒子没有质量，这是实验事实。强、弱、电三种基本相互作用由规范对称性所控制。规范对称性和手征对称性要求矢量中介玻色子、夸克和电子等基本粒子不能直接带有质量。作为标准模型的重要组成部分，对称性自发破缺机制调和了对称性要求与实验事实之间的矛盾。发现Higgs粒子，是对这一机制的重要确认。对这一机制背后物理的探索，构成了二十一世纪粒子物理学的重要研究课题。
2A historical perspective aboutthe 2016 Kosterlitz-Thouless Nobel Physics Prize
报告人：Jorge V. Jose
时间：6月12日（周二）10:00
单位：中科院理论物理所
地点：6620会议室
3High Performance Computing, Attosecond Physics and Deep Learning
报告人：陈少豪，Louisiana State University
时间：6月12日（周二）10:00
单位：清华大学
地点：物理系理科楼B315
High-performance computing (HPC) plays a key role in nowadays scientific research. Computer clusters and GPUs are widely used in science and engineering. In this talk, I will first briefly introduce HPC and its recent development, then I will show applications of HPC in two research fields. (1) Attosecond physics. Especially we analyzed ultrafast phenomena in attosecond transient absorption spectrum. (2) Deep learning in quantum physics. We applied a convolutional neural network model to deal with the Schrodinger Equation. The model was learned from data.
报告人：杨蔚，中科院地质与地球物理研究所
时间：6月12日（周二）10:30
单位：中科院物理所
地点：M236会议室
纳米离子探针能够在微纳尺度上实现对同位素和微量元素进行点、面、深度剖面的精确测定，在地球科学、空间科学、材料科学和生命科学等领域有广泛的应用。随着科学的发展，其对分析技术的要求也不断提高，要么需要更高的空间分辨，要么需要更高的分析精度。报告将分别以锆石U-Pb定年和硫化物S同位素分析为例，介绍我们基于纳米离子探针提升空间分辨和分析精度的策略。这些策略也可以应用于其它纳米离子探针的分析方法，从而实现更加广泛的应用。
5 Design and Engineering of Interfaces/Interphases for Stable Li Anodes
报告人：王东海
时间：6月12日（周二）11:00
单位：中科院物理所
地点：ABII402会议室
Li metal and Li-alloy based anode materials are the most promising anodes for next-generation Li batteries. The poor interfacial stability (unstable solid-electrolyte interphase (SEI)) in the battery has been the primary issue hindering their practical application. In this talk, I will present a strategy to reinforce the SEI with desired properties including good tolerance to the Li-based material volume change and efficient surface passivation against electrolyte penetration. The strategy works via introducing multiple functional components bonded to the Li-based material surface into the SEI. The SEI reinforced shows much better stability than the SEI reinforced by electrolyte additive strategy, which is the current state-of-art and commercially used solution to SEI stability issue.
报告人：Chengtian Lin, Max Planck Institute for Solid State Research
时间：6月12日（周二）13:30
单位：清华大学
地点：理科楼C302报告厅
This talk gives an introduction of the history of high temperature superconductor materials since the first discovered cuprate YBCO with Tc=92 K in 1986, followed on the development of other high Tc Type II compounds, including NaxCoO2, iron-based (iron-age) pnictides and topologicals. Although the Tc of newly discovered materials is not higher than cuprates, an entire new field on superconductivity has been opened, established and still in progress. The talk also gives some typical samples of superconductors in their preparation, crystal growth and characterization. Finally present a short video to show the live crystal growth experiment using floating zone method.
It is a realistic challenge in materials sciences to search for new superconducting materials with higher Tc and/or to enhance Tc of the known superconducting materials. A message that the author would like to pass to researchers, especially young researchers and graduate students, is not to give up the challenges to the problems of high-temperature superconductivity.
报告人：Donglin Ma，HUST
时间：6月12日（周二）14:00
单位：清华大学
地点：蒙民伟科技南楼S72
I will focus on the optical system design of the 12-meter large optical-infrared telescope, and systematically introduce the optical design methods and the basic principles followed by the design of astronomical optical system, especially large telescopes. I will further discuss the way to evaluate the optical performance and scientific performance of the telescope based on different evaluation criteria. Specifically, the report will systematically compare the optical and scientific performance of classical RC system (three-mirror) and SYZ system (four-mirror). Finally, I will share some of the prospects and plans for the development of future telescopes and astronomical instruments, taking into considerations of the domesitc technical foundation, especially at Tsinghua (THCA), Huazhong University of Science and Technology, and other domestic institutions; with the international collaboration opportunities.
报告人：廉超，中科院物理所
时间：6月13日（周三）10:00
单位：北京师范大学
地点：物理楼106
基于Kohn-Sham方程、无参数的密度泛函理论(DFT)，在研究预测材料电子结构、磁结构和电声耦合等方面已经取得巨大的成功。其含时推广即含时密度泛函(TDDFT)，通过求解含时Kohn-Sham方程，并在Hamiltonian中引入光场效应，可以完全第一性地处理电子-声子-光子的相互作用及其含时演化。因此，TDDFT成为研究光致动力学一种有效可靠的方法。本次报告，我们将介绍自己的TDDFT实现、算法改进及其应用，包括光生载流子的动力学，晶格的非热相变，光致生磁等。
报告人：Evangelie Athanassoula
时间：6月13日（周三）12:00
单位：北京大学
地点：first floor meeting room, KIAA
Using high resolution numerical simulations -- addressing the dynamics, the star formation, and the chemical evolution -- we follow the formation of disc galaxies during wet major mergers in which each protogalaxy is embedded in a hot gaseous halo. We witness the destruction of the discs of the protogalaxies and the inside-out formation of a new disc, which is both massive and extended. We also witness the formation of a classical bulge component whose mass relative to the disc varies from one run to another, taking values that cover all the range from lenticulars to spiral galaxies. The rotation curves of our model galaxies are found to be flat. In all our simulations the disc has substructures, such as bars, lenses, spirals and rings, with realistic morphology, including ansae and boxy/peanut bulges. We will briefly discuss some dynamics of these substructures, as well as the formation and properties of the thin and thick disc components. Last but not least, we will present results on metallicity and make comparisons with observations in the bar/bulge regions of our Galaxy.
报告人：韩伟, 北京大学量子材料科学中心
时间：6月13日（周三）13:30
单位：清华大学
地点：理科楼C302报告厅
Quantum materials have recently exhibited many unique spin-dependent properties, which could be promising material candidates for spintronics. On the other hand, pure spin current, flow of spin angular momentum without the company of any charge current, can be a useful probe for interesting quantum materials/states.
In this talk, I will present our recent experimental results on using pure spin current as a probe for topological insulators, spin superfluid ground states, and the interface at ferromagnetic-superconductor heterostructures. I will first talk about the pure spin current in SmB6 and resonant magnon absorption in (BixSb1-x)2Te3, which are consistent with the spin-momentum locked properties of the topological surface states. Then I will discuss the pure spin current transport in canted antiferromagnet Cr2O3, suggesting the existence of spin superfluid ground state at low temperatures. The last part of my talk will talk about the spin dynamics in an s-wave superconductor in the heterostructures of ferromagnet/superconductor, from which the superconducting gap properties at the interface could be inferred.
11Eigenstate Thermalization Hypothesis in 2D CFT and its implication to AdS/CFT
报告人：Feng-Li Lin，Taiwan Normal University
时间：6月13日（周三）14:30
单位：中科院理论所
地点：Conference Room 322, ITP main Building
In this talk, I will discuss ETH in 2D CFT in the large central charge limit based on my works done in the past 2 years with my collaborators. We calculate the entanglement entropy, Renyi entropies and various dissimilarity distance measures to compare the eigenstates and thermal states in the short-interval expansion. Our results reveal the subtlety of thermalization in 2D CFT and its implication to quantum gravity nature of the dual AdS gravity.
12 Novel Interaction and Topological Effects in the Electronic and Optical Properties of Two-Dimensional Materials
报告人：Ting Cao
时间：6月13日（周三）14:30
单位：北京大学
地点：Room W563, Physics Building, Peking University
Recent advances in the experimental and theoretical studies of atomically thin two-dimensional (2D) materials have opened up opportunities in exploring new phenomena and properties as well as related applications absent in conventional bulk materials. In the first part of my talk, I will present our theoretical studies on the quantum excited-state phenomena in monolayer transition metal dichalcogenides and gapped few-layer graphene. By theoretical analyses and ab initio GW-BSE calculations, we discover excitons with exceptional binding energies due to the reduced dielectric screening in 2D (thus dominating their optical spectrum) and unusual optical selection rules resulting from a nontrivial topological band effect which occurs only in 2D. In the second part, I will discuss our discovery of topological phases in graphene nanoribbons. The topological phases enable us to rationally design a prototype graphene nanoribbon superlattice that hosts a coupled array of non-trivial junction states. I further connect our theoretical predictions to experimental results and demonstrate their potential applications.
13Exploring Proximity Coupling for Novel Spin-Dependent Phenomena
报告人： Jing Shi
时间：6月13日（周三）16:00
单位：北京大学
地点：Room W563, Physics Building, Peking University
In heterostructures made of two dissimilar materials, proximity coupling at the interface can have profound consequences on the physical properties of both. Numerous examples exist in condensed matter physics. I will present our recent work on proximity effects to induce spin-orbit coupling (SOC) and exchange interaction. In graphene/transition metal dichalcogenide (TMD) heterostructures, we have successfully induced up to 1.5 meV in Rashba SOC (two-three orders of magnitude greater than the intrinsic SOC strength) in graphene measured by quantum transport. To induce exchange interaction, we have exploited atomically flat rare-earth iron garnet films (e.g. yttrium iron garnet- YIG and thulium iron garnet- TIG) as the source of the exchange and demonstrated strong exchange interaction in graphene and the surface states of (Bi, Sb)2Te3 topological insulator. These two interactions are essential ingredients for realizing the quantum anomalous Hall state in both systems, which is very exciting for potential spintronic applications.
报告人：裴国玺
时间：6月13日（周三）18:30
单位：中国科学院大学
地点：雁栖湖校区教1-113
报告人：Wanzheng Hu，Boston University
时间：6月14日（周四）10:00
单位：中科院物理所
地点：M楼236报告厅
Using ultra-short laser pulses to drive quantum materials out of equilibrium is an emergent technique for dynamical materials control. Selectively driving low-energy excitations using femtosecond laser pulses can achieve novel quantum phases inaccessible at equilibrium.
Combining dynamical light control with ultra-broadband transient optical spectroscopy, we are able to directly probe the dynamics of lattice vibrations and electronic excitations over the whole far-infrared region, revealing the physics behind the transient quantum phases. In this talk, I will present our recent work on light-induced transient superconductivity in bilayer and trilayer cuprates.
16Exploring Proximity Coupling for Novel Spin-Dependent Phenomena
报告人：Shi Jing, Department of Physics & Astronomy, University of California
时间：6月14日（周四）10:00
单位：清华大学
地点：理科楼C109会议室
In heterostructures made of two dissimilar materials, proximity coupling at the interface can have profound consequences on the physical properties of both. Numerous examples exist in condensed matter physics. I will present our recent work on proximity effects to induce spin-orbit coupling (SOC) and exchange interaction. In graphene/transition metal dichalcogenide (TMD) heterostructures, we have successfully induced up to 1.5 meV in Rashba SOC (two-three orders of magnitude greater than the intrinsic SOC strength) in graphene measured by quantum transport. To induce exchange interaction, we have exploited atomically flat rare-earth iron garnet films (e.g. yttrium iron garnet- YIG and thulium iron garnet- TIG) as the source of the exchange and demonstrated strong exchange interaction in graphene and the surface states of (Bi, Sb)2Te3 topological insulator. These two interactions are essential ingredients for realizing the quantum anomalous Hall state in both systems, which is very exciting for potential spintronic applications.
报告人：李东海（Dung-Hai Lee），美国加州大学伯克利分校物理系
时间：6月14日（周四）13:30
单位：清华大学
地点：理学院郑裕彤讲堂
Raising the superconducting transition temperature to a point where applications are practical is one of the most important challenges in science. In 1986 a family of superconducting materials, namely the copper-oxide superconductors, was discovered. To date, the highest transition temperature is ~140K. However, despite unprecedented research efforts, the precise cause of the high transition temperature is still controversial. In 2012 a new interface high-temperature superconducting system was discovered. This system is based on entirely different materials. However, it shares many common features with the copper-oxide superconductors. Moreover, the reason underlies its high transition temperature has been found in the last few years. In this talk, I shall explain the mechanism for strong Cooper pairing in this system and what it teaches us about finding even higher temperature superconductors.
报告人：Neal Katz，Univ. of Massachusetts
时间：6月14日（周四）10:00
单位：清华大学
地点：蒙民伟科技南楼S727
QSO absorption line studies of the CGM using HST COS are the best direct way to study the accretion and galactic wind processes that are thought to dominate galaxy formation. Detailed numerical simulations are critical to interpret and understand these observations. Unfortunately, simulations are sensitive to wind implementations. Interactions at wind/halo gas interfaces in the CGM occur on scales that are much below the resolution of any current or near future galaxy formation simulation, making a "brute force" approach not viable. To mitigate this impasse, we propose to implement a new wind algorithm that explicitly models the "subgrid physics" in the wind-halo gas interaction analytically within a simulation, using the simulation to provide the physical characteristics that will inform the interaction. Unavoidably, this introduces a few free parameters but we can restrict them by matching observed galaxy Previous simulations using a more standard wind model approaches reproduced many observed properties of galaxies and metal-line absorption, but our new wind implementation will allow us to tie empirical successes, and failures, more securely to the underlying wind physics, both the ejection (mass-loading factors and ejection speeds) and the interaction between the wind and gaseous halo, and allow us to identify absorption line features with specific physical processes.
19Airborne and underground matter-wave interferometers: geodesy, navigation and general relativity
报告人：Philippe Bouyer, Laboratoire Photonique Numerique Nanosciences
时间：6月15日（周五）10:00
单位：北京大学
地点：Lecture hall 2736, Science building 2, Peking University
The remarkable success of atom coherent manipulation techniques has motivated competitive research and development in precision metrology. Matter-wave inertial sensors ? accelerometers, gyrometers, gravimeters ? based on these techniques are all at the forefront of their respective measurement classes. Atom inertial sensors provide nowadays about the best accelerometers and gravimeters and allow, for instance, to make the most precise monitoring of gravity or to device precise tests of the weak equivalence principle (WEP). I present here some recent advances in these fields:
The outstanding developments of laser-cooling techniques and related technologies allowed the demonstration of an airborne matter-wave interferometers, which operated in the micro-gravity environment created during the parabolic flights of the Novespace Zero-g aircraft. Using two atomic species (for instance 39K and 87Rb) allows to verify that two massive bodies will undergo the same gravitational acceleration regardless of their mass or composition, allowing a test of the Weak Equivalence Principle (WEP).
New concepts of matter-wave interferometry can be used to study sub Hertz variations of the strain tensor of space-time and gravitation. For instance, the MIGA instrument which is currently built in France, will allow the monitoring of the evolution of the gravitational field at unprecedented sensitivity, which will be exploited both for geophysical studies and for Gravitational Waves (GWs) detection.
The starting point for many experiments aimed at studying fundamental physics is to prepare a pure sample in terms of its energy, spin and momentum before injecting into an atom interferometer, spectrometer or quantum simulator. I will present an all-optical technique to prepare ultra-cold sample in magnetically insensitive state with high purity, a versatile preparation scheme particularly well suited to performing matter-wave interferometry with species exhibiting closely separated hyperfine levels, such as the isotopes of lithium and potassium.
I will finally discuss how precision atom interferometry can be used to perform long-term, drift-free integration even in the harsh environment of the plane, and thus provide a new tool for precision measurement and navigation.
报告人：韩一龙，香港科技大学
时间：6月15日（周五）14:00
单位：北京师范大学
地点：物理楼106
胶体（Colloid）是一类重要的软物质。胶体粒子作为“大原子”，可以形成各种晶体，玻璃态，液体等相，因此可以用来研究相变，晶体缺陷运动等基础物理和材料学的问题。微米胶体粒子即使在稠密的三维胶体晶体或玻璃态的内部，其布朗热运动也可在光学显微镜下直接观察，通过图像处理得到每个粒子运动轨迹，从而可以研究相变在单粒子尺度上的过程，这是原子分子系统中难以达到的。近年来各种大小，形状，相互作用势可调的粒子逐渐制备成功，可组成复杂丰富的相，为相变研究提供了广阔的平台。这里主要介绍本组近年来利用胶体系统对晶体熔化，固固相变和玻璃态转变的一些研究。
3. 太阳能电池的明天
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