1993年量子力学考研试题 设n)是粒子数算符N=的本征函数,相应之本征值为 n20),算符a和满足对易关系aa-a=1。证明:an)(其中 n≥1)和an)也是N的本征函数其相应的本征值分别为-)和+) 解:用粒子数算符N作用到an)上,即 Nan=aaan=laa a n-a GN n)-an)=(n-1 an 上式表明an)是N的本征态,相应的本征值为(n-1)
Theories and Experiments The goal of physics is to develop theories based on experiments A theory is a \guess,\expressed mathematically, about how system works The theory makes predictions about how a system should work Experiments check the theories' predictions Every theory is a work in progress
1 Faraday's law of electromagnetic induction 1. Experiments ① A magnet and ② two loops of wire,a loop of wire battery and a switch A current is observed in the loop as long as the magnetic flux through the loop is changing with time
