1. The problem statement, all variables and given/known data A hydrogen atom is in state (|210>+|211>)/sqrt(2) relative to some fixed coordinate system. Assume only E1 transitions contribute. To which direction in space the rate of emission will be minimal? 2. Relevant equations The rate of emission is proportional to [tex]|<F|X|I> \cdot \epsilon|^2[/tex] where F is the final state and I is initial state. F=(|210>-|211>)/sqrt(2) I=(|210>+|211>)/sqrt(2) epsilon is polarization vector. 3. The attempt at a solution I don't know how to find epsilon here, the TA said that <F|X|I> should be complex valued but if I am not mistaken it equals 0.5(<210|X|210>-<211|X|211>), and this is real valued.