@123 You can imagine the origin of the coordinate system at B, and the diagram in the 2nd picture has just drawn an (x,z) plane at $y = - l$ to highlight the similarities with the A case

@bolbteppa Thanks. for the confirmation , the same results i have concluded by thinking origin at B.

Is there any physical meaning of magnitude and direction of angular momentum? Because different origin give different magnitude and direction of angular momentum and torque.

@Obliv miehehehe

if i parameterize the unitary matrices with the generalized gellmann matrices, is the parameterization periodic?

i think the answer is no

hmm

amazing