Fundamental Concepts Screen (a) (b) hCafbeasomtkXawansaaeaeaomdstpask experimentally observe is more like the situation in Figure 1.2b.In other words,the SG apparatus splits the original silver beam from the oven into two distinct components,a phend referred to in the early days f quantum theory as“space quantization.”To the extent thatμcan be identified within a proportionality factor with the electron spin S,only two possible values of the z-component of S are observed to be possible,S.up and,which we call+and S..The two possible values of are multiples of some fundamental unit of angular momentum;numerically it turns out that S.h/2 and-h/2,where 方=1.0546×10-27erg-s =6.5822×10-16cV-s (1.1.3) This "quantization"of the electron spin angular momentum is the first important feature we deduce from the Stern-Gerlach experiment. Of course,there is nothing sacred about the up-down direction or the e beam proceeding in the y-direction.In this manner we could have separated the beam from the oven into an S,component and an S,-component. Sequential Stern-Gerlach Experiments Let us now consider a sequential Stern-Gerlach experiment.By this we mean that the atomic beam goes through two or more SG apparatuses in we consider is relatively straightforward Figure 1.3a,where SG2 stands for an apparatus with the inhomogeneous magnetic field in the z-direction,as usual.We then block the S.-compo-