Suppose two spin-1/2 particles are known to be in the singlet configuration (Equation 4.176). Let S_α⁽¹⁾ be the component of the spin angular momentum of particle number 1 in the direction defined by the vector a. Similarly, let S_b⁽²⁾ be the component of 2’s angular momentum in the direction
b. Show that

where θ is the angle between a and b.

Equation 4.176

Transcribed Image Text:

- = ( 12³5 (³5) ħ² - cos 8, 4 (4.225)