# Operators and commutation of operators

1. Aug 15, 2012

### solas99

why is only one component of angular momentum is quantised, and what determines which component is quantised?

2. Aug 15, 2012

### shahbaznihal

All components of Angular momentum are quantized but it is much easier to work with only the z component. And since space is isotropic, it does not really matter which direction you use. However, z component is simpler to work with mathematically.

3. Aug 16, 2012

### karlzr

Different components of angular momentum do not commute, so they cannot be quantized at the same time. Of all the components, z component is the easiest to deal with.

4. Aug 16, 2012

### Jorriss

Do you mean can not be simultaneously diagonalized? All three are quantized simultaneously.