ABSTRACT
To a mathematician the funny ⊗ has a speci c meaning (they call it the tensor product). For us, it simply indicates that two independent aspects of the state have to be combined to get the full picture. In general terms one could write
⊗ S
with S〉 being the spin state of the system and Ψ〉 the spatial state, the part that deals with energy, momentum, etc. e spin information is not contained within the spatial state; that has to be dealt with separately.1
