Quantum Mechanics Solution Manual 

© Leon van Dommelen 

5.5.1.1 Solution complexsaa
Question:
What is the normalization requirement of the wave function of a spin particle in terms of and ?
Answer:
The particle must be found somewhere, either with spin up or with spin down. The total probability of finding it somewhere with spin up is , and the total probability of finding it somewhere with spin down is . The sum of the two integrals must be one to express the fact that the probability of finding the particle somewhere, either with spin up or spin down, must be one, certainty.