2 Exercise. Prove it. ◦ In fact, as sophisticates can show you, on a complex space a linear operator which preserves all norms will also preserve all inner products. But the key thing is to remember is that a unitary operator preserves all inner products (and therefore all norms). • This is analogous to the fact that translations and rotations in ordinary three-dimensional space preserve distan...

Starting from the simplest possible building blocks—a ket, a bra, a time-reversed ket, and a time-reversed bra— a diagrammatic formalism is developed for angular momentum coupling problems. The formalism comprises Clebsch–Gordan coefficients as well as 3jm-symbols. The idea of constructing invariants (internal lines) by contracting contragredient pairs of quantities is emphasized throughout. Th...

Currently it is not known how to experimentally measure the contribution of the orbital angular momentum of the quarks to the total spin of the nu-cleon. By examining the quark orbital angular momentum we find that it does not satisfy the standard angular momentum commutation relationships. Thus aside from the experimental difficulty in measuring the quark angular momentum, this indicates that ...