费曼“疑难问题”初探  

A PRELIMINARY STUDY ON FEYNMAN'S “PUZZLE”

作　　者：徐湛[1] 

机构地区：[1]清华大学物理系,北京100084

出　　处：《物理与工程》2017年第6期27-30,共4页Physics and Engineering

摘　　要：本文试图回答《费曼物理学讲义第3卷》第13-8节中提出的一个"疑难问题",即该讲义导出了在有吸引性缺陷的一维晶格中,存在着一个处于能带上方的束缚态能级,那么其物理意义是什么?我们的分析方法包括:构造新的捕陷态,找出该问题的全部可能的解,以及对散射振幅重新进行解析延拓。各种方法导致的结论是一致的,即确实存在着费曼所说的那个处于能带上方的一个束缚态能级,然而该晶格的缺陷一定是排斥性的,而不能是吸引性的。This paper tries to answer the ＂puzzle＂ in Section 13-8 of Feynman Lectures on Physics Volume 3,which claimed that in a one-dimensional lattice with an attractive imperfection there is a bound state above the energy band,and asked what its physical meaning is.Our analysis includes constructing a new trapped state,finding all possible solutions to the problem and reanalyzing the analytic continuation of the scattering amplitude.Various methods lead to a consistent conclusion that indeed there is an energy level of bound state above the energy band as Feynman said,but the lattice imperfection should be repulsive instead of attractive.

关 键 词：晶格缺陷 捕陷态 束缚能级 散射振幅 解析延拓 

分 类 号：O77[理学—晶体学]