The angular momentum can be in a different direction than the angular velocity - but in this case, I is not a scalar quantity. Here is the short scoop on the angular momentum principle.

By splitting a single photon, scientists confirmed that angular momentum is always conserved — a billion-to-one experiment that reinforces the foundations of quantum physics.

In a new study published in Nature Physics, scientists have achieved the first experimental observation of phonon angular momentum in chiral crystals.