Spin The Facts I will begin by stating the bare facts briefly, at the cost of some precision. Any quantum-mechanical system possesses angular momentum, sometimes called spin 1 .
Angular momentum is quantized, that is it is always an integer multiple of .
Traditionally, stands for angular momentum 2 . Say we measure the component of angular momentum along some axis, say the -axis. Let stand for this component. A more precise definition of is the maximum possible value for . The same result holds for the component of angular momentum measured along any axis.