关于高温超导机理的一个模型 | 本周物理学术讲座

1关于高温超导机理的一个模型 

报告人：薛其坤，清华大学

时间：9月14日（周三）16:00

单位：北京大学量子材料科学中心

地点：物理楼西563会议室

根据最近的实验进展，我们提出了一个关于高温超导的简单模型。利用这个模型可以相对简明地解释复杂的高温超导相图等问题。我还将针对这一模型，对未来的实验和理论工作给出一些建议。

2从墨子到“墨子星”/ From Mo Zi to the Mo Zi Satellite

报告人：吴令安，中科院物理研究所

时间：9月13日（周二）15:00

单位：中科院理论物理研究所

地点：新楼6420报告

虽然光（和视觉）是人类认识世界的最重要手段，光学作为一门科学也是最古老的学科之一，但我们至今还在研究光的基本性质，不断地将光学应用、推广到实际应用。本报告将简要回顾以墨子为代表的中国对古代光学的贡献，以及中国量子光学近二十多年的发展史，直到今年量子科学实验卫星“墨子号”的发射。本报告也将简要介绍量子通信的基本概念，并力图澄清关于量子保密通信的误区以及媒体的误导。

3Stochasticity and robustness in S-phase duration from genome replication kinetics

报告人：Qing Zhang，Universite Pierre et Marie Curie

时间： 9月13日（周二）10:30

单位：中科院理论物理研究所

地点：新楼6420报告厅

Genome replication, a key physiological process for a living cell, typically relies on intrinsically stochastic initiation by replication origins, causing a variability of replication timing from cell to cell. Over evolution, an organism can control only the propensity of origins to initiate and their position, but it does not eliminate completely this uncertainty. While widely accepted mathematical models of eukaryotic replication as a stochastic process are available, the question of the link between the controllable parameters and the resulting distribution of global replication timing has not been addressed systematically.

Here, we propose a combined analytical and computational approach to this question. Our calculations give a simple way to understand how positions and strengths of many origins lead to a given distribution of total duration of the replication of a large region, a chromosome or the entire genome. Specifically, the total replication timing can be framed as an extreme-value problem, since it is due to the last region that replicates in each cell. Our calculations lead us to identify two regimes based on the spread between characteristic completion times of all inter-origin regions of a genome. For widely different completion times, timing is set by the single specific region that is typically the last to replicate in all cells (and is hence "fragile"). Conversely, when the completion times of all regions are comparable, an extreme-value estimate shows that the cell-to-cell variability of genome replication timing has universal properties. Comparison with available data shows that the replication program of two yeast species falls in this extreme-value regime.

4粒子物理的高强度前沿和我国的强流质子加速器

报告人：李小源，中科院理论物理研究所

时间： 9月13日（周二）12:00

单位：中科院理论物理研究所

地点：322报告厅

能量和高强度是粒子物理的两大前沿。高强度前沿的实验，利用精准测量去寻找稀有过程以及和标准模型预期值的极小偏离，并通过它们掲示在非常高能量处的新物理规律。因而，在寻找超出标准模型新物理中, 这两大前沿上的实验所起的作用是相互补充的。但是，在许多情况下，高精度实验探测的有效能量标度要远超出高能加速器之所及。高精度实验通常要求最大可能的束流强度和极其灵敏的探测器。我国已经获准建设和纳入第十三个五年计划的CSNS, HIAF和CADS 高功率强子加速器均能提供高强度的质子束流。特别是CADS 设计的质子平均束流强度和功率预计将达到国际领先水平，从而为在我国开展具有国际先进水平的低能量高强度粒子物理实验和理论研究创造了很好的条件。如果国内从事加速器，实验和理论的同事们能结合起来，共同规划筹建在CSNS, HIAF 特别是CADS上的 Muon, Pion, Ultra-Cold Neutron 以及Neutrino 等束流线并开展相应的实验和理论研究，一定能作出国际一流水平的粒子物理工作，并争取有所发现。

内容：

1）50年前有关我国如何发展以加速器为基础的粒子物理的讨论

2）上世纪80年代初杨振宁先生对国际高能物理发展前景的展望

3）当今我国强流质子加速器建设给粒子物理高强度前沿带来的机遇

4）粒子物理与宇宙学中的能量标度和建造未来超大型对撞机的风险

5自旋玻璃：理论方法及网络科学应用

报告人：周海军，中科院理论物理研究所

时间： 9月13日（周二）19:00

单位：中科院大学雁栖湖校区

地点：雁栖湖校区教1-009

6Exotic Quantum States in Heavy Fermion systems 

报告人：路欣，浙江大学  

时间：9月14日（周三）11:00

单位：清华大学物理系

地点：理科楼三楼报告厅（C302）

Heavy fermion materials have served as a classical prototype of strongly correlated electron systems (SCES), where exotic quantum states emerge, such as anti-ferromagnetism, superconductivity and multipolar orbital ordering, due to the correlation effects between localized f and conduction electrons. In the first part of the talk, I will discuss the Cd-doping and pressure tuning of the heavy fermion superconductor CeCoIn5, where and spin-droplets nucleate around the Cd-dopants forming an inhomogeneous electronic state, in contrast to the general uniform tuning scenario. In the second part, we focus on the “hidden order” in some heavy fermion materials such as URu2Si2 and PrFe4P12 in particular. Point-contact spectroscopy is applied to explore the nature of the “hidden order” to reveal the dichotomy of localization and itineracy in f electron systems.

7光学表征方法简介及钙钛矿光电性质研究

报告人：刘新风，中科院国家纳米中心

时间： 9月14日（周三）15:10

单位：北京大学物理学院现代物理研究所

地点：3教208教室

我们首先介绍影响材料光学性质的一些因素和常用的稳态光学表征方法和手段，包括吸收光谱、荧光光谱、拉曼光谱等；第二部分在了解飞秒激光器的工作原理和特点基础上，介绍两种常用的时间分辨光谱手段，时间分辨荧光光谱和瞬态吸收光谱；第三部分将重点介绍我们组在钙钛矿光电性质方面的一些研究基础和最新进展。

8Van der Waals Stacking: a powerful paradigm to expand the 2D horizon

报告人：Jurgen H. Smet，Max Planck Institue for Solid State Research

时间： 9月14日（周三）16:00

单位：清华大学物理系

地点：理科楼郑裕彤大讲堂

The most prominent representative among the strictly two-dimensional materials is no doubt graphene. It is gifted with outstanding electrical, thermal and mechanical properties. It’s very responsive to its environment, since interactions of any material with the environment proceed through the surface and 2D materials are nothing but a surface. This may be a blessing for sensing, but can also be a curse as it frequently degrades the electrical properties. Attempts to alleviate the detrimental impact of environment have been the key impetus for the development of 2D material stacks in which graphene is encapsulated between boron nitride layers. It drastically reduces the influence of the environment and it is possible to enhance graphene’s electrical conduction properties significantly. This straightforward example can however be generalized to generate more complex so-called van der Waals heterostructures with more elaborate sequences of 2D materials. This presentation will motivate the need for van der Waals stacking to bring out the best of 2D materials and will give a flavor of how powerful van der Waals stacking can be to create designer heterostructures with engineered properties. It will address just a few of the simplest examples, both covering applied and basic sciences, but they will bring the point home that van der Waals stacking is a truly powerful paradigm.

更多报告信息：中国物理学会期刊网学术讲座列表

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