Applied Quantum Mechanics, Second Edition

Exercise 8.1
A particle of mass m is in a one-dimensional, rectangular potential well for which V( x) = 0 for 0 < x < L and V( x) = ? elsewhere. The particle is initially prepared in the ground state ? 1 with eigenenergy E 1. Then, at time t = 0, the potential is very rapidly changed so that the original wave function remains the same but V( x) = 0 for 0 < x < 2 L and V( x) = ? elsewhere. Find the probability that the particle is in the first, second, third, and fourth excited state of the system when t ? 0.
Consider the same situation as (a) but for the case in which at time t = 0 the potential is very rapidly changed so that the original wave function remains the same but V( x) = 0 for 0 < x < ?L, where 1 < ? < 5, and V( x) = ? elsewhere. Write a computer program that plots the probability of finding the particle in the ground, first, second, third and fourth excited states of the system as a function of the parameter ?.
Exercise 8.2
The coulomb potential energy in real space between charges e and ? e is
where ?