【摘要】 一维无限深方势阱阱壁的受力计算是量子力学教科书中经常遇见的一个习题,最近其在量子非平衡过程的研究中也吸引了不少研究兴趣.本文提出了一个力算符的定义,利用它可以非常方便地重新得到之前的结果.当阱壁随时间移动时,该算符的正确性也得到了数值验证.这个方法的优点在于避免先引入有限深方势阱计算平均力后再取阱深为无限大的极限过程.计算表明,在量子情形下引入含时正则变换再定义力算符的方法既不正确也无必要.更多还原

【Abstract】 Calculation of the mean force applied on the wall of one-dimensional infinite square-well potential is an exercise that is frequently met in quantum mechanics textbooks. Recently,it also attracts interesting in the study of quantum nonequilibrium processes. In this paper,a force operator is proposed and is utilized to re-obtain previous result. Its correctness is as well proved in the case of one wall moving at constant velocity. The advantage of the operator is that a process of taking limit does not need,where one has to calculate the mean force for a finite square-well potential first and to take the potential-depth be infinite later. The computations show that,in quantum regime using a time-dependent canonical transformation to define a force operator is neither correct nor essential.更多还原