I have been reading about Feshbach resonance in ultra cold atoms and there were some areas I'd like to understand better/have questions about:
i) As the atoms approach each other, can their spins be in any orientation? The literature isn't explicit. My assumption is they win have random spins, I wanted to check this is the right assumption. I.e. in a BEC, are the spins still uncorrelated?
ii) In which direction would the magnetic field have to be applied? As the atoms are moving in a random motion, would it just be a uniform magnetic field? Again - my assumption is it would be a simple magnetic uniform field if the spins are indeed random.
Thanks in advance!