Griffiths Introduction to Elementary Particles · Problem 4.18

Bound States — David J. Griffiths

Physics — QFT · spin-measurements-general-spinor

Problem

Suppose an electron is in the state

\begin{pmatrix} 1/\sqrt{5} \\ 2/\sqrt{5} \end{pmatrix}

. (a) If you measured

S_x

, what values might you get, and what is the probability of each? (b) If you measured

S_y

, what values might you get, and what is the probability of each? (c) If you measured

S_z

, what values might you get, and what is the probability of each?