当代理论物理发展趋势之我见——杨振宁学术思想启发的若干思考

My prospective on the contemporary trend of theoretical physics inspired by Chen-Ning Yang

欣逢杨振宁先生百年诞辰,已有不少文章总结了杨先生对当代物理学发展的重要科学影响.笔者认为,作为当代最伟大的理论物理学家之一,杨先生不仅以诸多具体的科学贡献推动了当代物理学革命性的进步,而且其独特的科学风格在国际学术界独树一帜,其学术思想更是深邃隽永、对中国和世界的物理学发展有长远的启发作用.笔者将结合学习杨振宁科学思想的体会,联系自己在理论物理研究方面的科学实践(包括在1992—1994年跟随杨先生对量子开系统、超导相变和冷原子物理方面的探索),对当代理论物理发展趋势提出一些个人的看法.文章将通过具体实例,阐述为什么要做"美或有用"的理论物理;为什么基本物理的理论在一段时间内可以与直接的实验验证保持距离?对于后者,本文还从科学方法论(哲学)的角度就理论预言与实验证实的关系进行较为深入的讨论.着眼于"有用"的理论物理-应用理论物理,笔者强调了国家需求驱动的科学研究与自由探索一样,也会导致基础物理的重要突破.

On the occasion of the centennial birthday of Mr. Chen-Ning Yang, many articles have summarized his important scientific influences on the development of contemporary physics. The author thinks that, as one of the greatest theoretical physicists, Mr. Yang in many scientific contributions has promoted the revolutionary progress of physics, and his unique style of science with deep and meaningful thoughts in academia has a longterm inspiration on developments of physics. Learning from Chen-Ning Yang’s scientific thoughts, the author will put forward some personal opinions on the development trend of theoretical physics with his own experiences in researching theoretical physics for 30 years, e.g., studies of quantum open system,superconducting phase transition and cold atom physics by following Mr. Yang in Stony Brook from 1992 to 1994. This article will elaborate why it is important to pursue “beautiful or useful” theoretical physics through some concrete illustrations;Why could the good theories in fundamental physics be kept at a distance from experiments for some time? For the latter, this article also argues the relationship between theoretical prediction and experimental confirmation from the perspective of scientific methodology(philosophy). Focusing on “useful” theoretical physics-the applied theoretical physics, the author emphasizes that scientific research driven by the national demand, as well as free exploration, can also lead to important breakthroughs in fundamental physics.