Of connections and fields—II

In the first part of this article¹ we gave an elementary introduction to Chern’s ideas and their impact on modern physics. In this concluding article we describe some more advanced applications of Chern’s ideas. This second part is some-what more demanding than the first part and is addressed to students with some background in mathematics and physics. Joseph Samuel is a theoretical physicist and by natural inclination a classical mechanic. Over the years he has strayed into other fields like optics, general relativity and very recently DNA elasticity. A unifying theme in his work is differential geometry and topology in physics. He keeps moderately fit by raising and lowering indices and relaxes by playing semiclassical guitar.     

Introducing quantum mechanics in the upper secondary school: A study in Norway

The study reported in this paper is a survey (n=236) that examines how upper secondary students (18-19 years old) in Norway come to terms with the wave-particle duality as presented as part of a short introduction to quantum physics. The main conclusion is that this concept is poorly understood. Some students demonstrate clear and explicitly formulated misconceptions rooted in a classical physics world-view. Scholars in physics have stated that the concept of duality is unnecessary, but still included in school and university physics. It is argued that school physics should give a more explicit focus to the challenge that quantum physics presents to the classical worldview, thus introducing the importance of an affective dimension in the learning and teaching of quantum physics. This study replicates evidence from other studies that wave-particle duality does not introduce such a challenge.     

The Pendulum as a Vehicle for Transitioning from Classical to Quantum Physics: History,Quantum Concepts,and Educational Challenges

In this article we use the pendulum as the vehicle for discussing thetransition from classical to quantum physics. Since student knowledgeof the classical pendulum can be generalized to all harmonic oscillators,we propose that a quantum analysis of the pendulum can leadstudents into the unanticipated consequences of quantum phenomenaat the atomic level. We intend to illustrate how classical deterministicphysical ideas are replaced by a point of view that contains bothdeterministic and probabilistic aspects. For example, the wave functioncontains probabilistic information but it evolves in time according toa fixed law, the Schrodinger equation. Discussion of the transition fromclassical to quantum thinking is historically grounded in the work oftwentieth-century physicists who developed quantum ideas. We seeapplication to current science in areas such as semiconductors, optics,GPS systems, and superconductivity. Our notion is that ascientifically-literatepublic should have a sense of the broad, conceptual schemes in modernphysics, as well as those associated with classical physics. We discusseducational challenges and strategies connected to including quantum theoryin a general education physics course. Our work would have otherapplications in college and secondary school settings.     

量子引力的各种探索

相对论和量子理论只是20世纪以来尚未完成的物理学革命的第一步,引力量子化是21世纪物理学中最大的难题。从突破量子场论中点粒子模型框架得到的超弦理论,尽管引入了新的对称性有助于统一四种基本相互作用,但量子超引力的重整化问题并没有彻底解决,目前也没有超对称与额外维的可靠实验证据。随着宇宙暴涨证据的发现,人们被迫重新引入爱因斯坦一度放弃的宇宙学常数,弦论很难解释为何宇宙常数是非常小的负数。从引力规范理论可以延伸出圈量子引力理论,它一开始就假定时空由离散元素构成,而且时空的离散性是结合量子理论与狭义相对论的结果。而扭量理论以因果关系为基本要素,重新构造事件的时空图。目前最成功的量子引力方法结合了三个基本思想：空间是突现的,空间的最基本的描述是离散的,这些描述都以因果性为基本要素,但这些构想如何与粒子物理、量子场论结合仍然是个未解之谜。     

The discovery of Dirac equation and its impact on present-day physics

The major events in the discovery of the Dirac equation and its interpretation are traced. The subsequent role it has played in the development of quantum field theory culminating in the Standard Model of present-day high energy physics is discussed. Rajasekaran is a theoretical physicist at the Institute of Mathematical Sciences, Chennai. His field of research is quantum field theory and high energy physics. Currently he is working in the area of neutrino physics.     

High School Teachers’ Understanding of Blackbody Radiation

This study is a detailed look at the level of understanding of fundamental ideas about blackbody radiation (BBR) among physics teachers. The aim is to explore associations and ideas that teachers have regarding blackbody radiation: a concept used routinely in physics and chemistry, which is necessary to understand fundamentals of quantum physics. In this explorative study, the responses of 106 high school physics teachers from 18 different cities in Turkey were examined using an online questionnaire during the 2014/2015 academic year. Male (88 %) and female (12 %) teachers with an average teaching experience of 17 years participated in this study. Teachers were asked about the concept of a “blackbody” and its radiation as well as about the closely related topics such as Wien’s law and the historic effect of understanding BBR on the development of modern physics. In this study, teachers’ spontaneous ideas about the BBR are depicted by “answer sculptures.” The answer sculpture is a new way of representing and categorizing responses provided by the participants. The analysis of answer sculptures revealed that the physics teachers’ factual knowledge and their conceptual understanding of the BBR are incomplete and even misleading. Here is what teachers we surveyed make of BBR as presented in our answer sculptures. This study is left at investigating teachers’ understandings of (1) blackbody radiation and (2) the significance of this scientific breakthrough.     

Snippets of physics

One of the celebrated results in black hole physics is that black holes have a temperature and they emit a thermal spectrum of radiation. Though a rigorous derivation of this result requires quantum field theory, a flavour of the essential ideas can be provided at an elementary level as indicated here. T Padmanabhan works at IUCAA, Pune and is interested in all areas of theoretical physics, especially those which have something to do with gravity. This is based on an article originally published by the author in Physics Education, Vol. 24, p.67, 2007.     

在《原子物理学》教学中如何培养学生的人文修养

原子物理学是近代物理的一部分,上承经典物理,下接量子力学,地位很重要。在教学过程中不仅要充分调动学生的求知欲望,培养学生的创新思维能力,还要培养学生高尚的道德情操,以提高学生的人文修养。     

关于量子力学教学的几点思考

量子力学在物理学研究中起着基础与支柱作用,因此量子力学课程教学自然成为本科物理教学一个极为重要的组成部分.结合教学实际,从教学内容、教学模式等方面,探讨了《量子力学》教学中应注意的问题并提出改进建议.     

《理论物理》课程教学初探

通过分析理论物理课程(主要是四大力学)的特点,探讨了理论物理教学中的一些思路和方法。本科阶段理论物理教学的目的主要是,在帮助学生掌握课程基本内容的基础上,重点是使其把握课程的基本思想和基本技能,着重培养学生的自学能力,从而为下一阶段的学习打下较为坚实的基础。因此在理论物理教学中,要注重培养学生的抽象思维能力和逻辑推导能力。该论文强调在对物理本质进行把握和理解的过程中使用抽象思维的形式,并通过训练能够熟练的提取所关心物理力学体系的动力学信息。     

学术争论对物质结构理论发展的推动作用

从古代物质结构的原子构成学说 ,17世纪气体分子运动论 ,到原子与分子物理学、化学物理学、生物物理学 ,至 192 5年量子力学建立的回顾 ,说明学术之争推动了物质构成理论的发展     

Exchange of identical particles in two dimensions

Exchange of identical particles is one of the theoretical ideas in quantum physics which was consistent with scattering experiments. There are subtle differences in the exchange phenomenon in a two dimensional plane as compared with our three dimensional world. This leads to the presence of a new class of particles calledanyons besides the two well-known universal categories (bosons and fermions) in the two dimensional plane.     

Fermion number fractionization

Solitons emerge as non-perturbative solutions of non-linear wave equations in classical and quantum theories. These are non-dispersive and localised packets of energy — remarkable properties for solutions of non-linear differential equations. In the presence of such objects, the solutions of Dirac equation lead to the curious phenomenon of ‘fractional fermion number’. Under normal conditions the fermion number takes strictly integral values. In this article, we describe this accidental discovery and its manifestation in polyacetylene chains, which has led to the development of organic conductors. (left) Kumar Rao is a Postdoctoral Fellow at PRL, Ahmedabad. He is interested in particle physics phenomenology as probed in particle colliders and formal aspects of quantum field theory. (right) Narendra Sahu is currently a postdoctoral fellow at Lancaster University, UK. His main research area includes Cosmology and Astroparticle physics. Currently he is working on dark matter and matter anti-matter asymmetry of the universe. (center) P K Panigrahi’s research interests are in the area of quantum computation, solitons in Bose Einstein condensates & nonlinear optical media. He is also deeply interested in science education and derives pleasure from long weekend walks.     

量子宇宙学中的逻辑问题

量子力学与广义相对论是20世纪物理学革命的产物,它们的本体论与认识论基础存在着尖锐的冲突,这就意味着以广义相对论与量子力学为基础的量子宇宙学的理论探索必定蕴含着大量没有澄清的哲学问题,广义相对论与量子力学相结合的量子引力理论的探索有可能需要在哲学逻辑方面的新突破。     

四端量子波导中电子的输运几率

量子波导理论研究不仅是对基础物理而且对量子器件研究具有重要意义,我们采用模匹配方法,研究了非均匀磁场下开放的四端量子波导中的电子输运性质。结果表明,从一端入射的电子可以透射到两个与之垂直的输出端和一个与之平行的输出端。在没有外加磁场的情况下,两个垂直输出端的输运几率是相同的,但垂直端与水平端的输运几率不同;在外加磁场下,由于磁边缘态效应,两个垂直输出的输运几率也有着相当大的差别。     

浅议两个谐振子的耦合

文章讨论了宏观及微观领域中两个谐振子的耦合问题,并就二者在解题方法、运动的描述和物理意义的解释方面的异同做了分析、比较,从而揭示经典力学与量子力学思想、方法的不同之处。     

The Wilsonian revolution in statistical mechanics and quantum field theory

We describe how Wilson’s concept of the renormalization group revolutionized our understanding of the physics of phase transitions, and of quantum field theory in general. We underline the key ideas of Wilson, based on earlier ideas of Landau, Ginzburg, Kadanoff and many others, which gave us an insight into the observed universality of diverse physical phenomena, and the remarkable efficacy of a few simple models to describe them.     

量子教育学:一百年前“量子爆破”的现代回声

牛顿—笛卡儿的机械世界观影响了整个工业化的历史。一百年前量子理论的兴起 ,如同在经典物理学城堡中发生的“科学爆破”,带来了一场科学和思想的革命。量子思维方式是适应信息社会发展特点的思维方式。深受牛顿—笛卡儿世界观影响的传统教育学 ,在信息社会将不可避免地走向衰微 ;新生的量子教育学与传统教育学在基本前提上存在着重大区别 ,它将在教育理论丛林中占据一席之地。“量子爆破”对量子教育学的创建有诸多启发     

利用量子化学软件分析分子器件上的电子输运性质

随着分子器件的测量和制备的技术不断突破,揭示电子输运机制的理论工作也得到了很大的发展。一些研究组分别发展了基于固体理论和量子化学的电子输运机制。实验证明,量子化学方法具有一定的优势。本文回顾了量子化学模拟方法的基本原理,并对其研究进展作了一个评述。