So, I thought I had an uneasy truce with quantum mechanics but I read something today which made spotted combat flare up in my mind again. In solid state semiconductor free electrons certainly have spin, and in order to "annihilate" meeting a hole, it also must certainly also have a spin. All this is perfectly acceptable to me, it is just this idea of a quasiparticle that is in essence a vacuum, an absence, having something as tangible and measurable as spin sits uneasy with me - for some reason. And I know that it is likely me, not the mass of knowledge on QM that is to blame. I suspect I am clinging to a far too "visual" imagination, most things quantum seem to be unsuited for mental visualisation.
My question is basically - how does hole spin interact with the electron spin? Does it work similarly as between any pair of electrons?
I read that in an exciton there are exchange interactions between hole and electron - and they can be both singlet and triplet. I can understand this, if they both have spin - certainly the bound state can be both singlet and triplet. I can also understand exchange interactions between electron and electron - but hole and electron? How? Imagining a sea of electrons with aligned spin, a hole's spin is thus related to the entire sea. The hole is an empty state, and it's state is defined by the state of all electrons in the stea. So this interaction is it an exchange between a single electron and the entire sea? But it is a short range range interaction... This does not compute...
PS: As must be obvious, I am not really a physicist. I am just an intrigued chemist.