Alan,
Nice links, as were those from Tom and Fred. I need to learn more (much more) of topology before I address an idea about the why and where-for of rotation empirically, and hence OAM. But I quite understand your fascination with the rotating helix as a key to understanding and inquiry, much like John Merryman loves vortexes. The thing is both can be found in the framework of Joy Christian's work if you follow the very practical comments of Jonathon Dickau on March 5 & 6. Once I have a better handle on terminology and usage I'll get back to this as the origin of rotation, but for now....
The rotating helix being a model of EMR is also a preferred idea of Peter Jackson, and one I've toyed with over the years in amateurish fashion. The problem is not with the concept but that it is not complete. While it provides the typical sinusoidal curve which is the signature of any electromagnetic inductance event, it does not provide an endpoint which is necessary by Planck.
E=hv states that the quantity of energy in the Planck Constant will be present in each and any wave event, and the photoelectric effect means it must be distinct. The helix, rotating or not cannot distinguish where that particle moment is. It depends on an observer position looking at the helix and saying 'Now'. Which if you think a moment, kind of stretches the relativity principle beyond rational bounds.
Say we have a large ball. Paint it black and put it out in space. Now we poke an axle through it and start it rotating gently. We hotwire a highway marking paint truck, load it on a rocket and go paint a reflective stripe on the ball pole to pole, so that we go from one pole to the other as the ball makes one full revolution. Now as a paradox twin is returning home he has a space buoy which when caught in the headlight of his spaceship will look for all the world like a big helix corkscrewing through space. Of course his headlight only shines on a portion of it but enough to see that it is helical. It's not really a regular helix though, there is probably a proper geometric name for the stripe so let's call it a 'helipoid' until somebody that knows corrects me.
Now. Whether a helix or helipoid, we have a picture of OAM. If we want a model of EMR and the signature the sinusoidal curve we can use the helipoid. The speed of axial rotation is constant but at the surface progressing from pole to equator the true speed on the stripe will increase to maxima, then fade back to axial speed at the other pole. This would mean that a repetitive event occurs in any wave event such that the density of energy changes with an expansion of size that maintains an equivalent angular momentia at any given point along the helipoid, while producing a true physical particle moment at the endpoints of the wave event. It just looks for all the world like a rotating helix.
If we want a model of an evanescent wave in the field of an electron, or electronic field of an atom, we can use the helix. It too is the signature of angular momentum. At origin of such a wave event the helix would look for all the world like a perfect circle but would still be a regular helix because the rotation progresses across time, it just has not started to propagate across space. And this is where topologically S2 morphs in deformation into S3.
Given pi is irrational, a true sustained finite length of radius would require rotation because the length on circumference would continually seek completion to behave spatially as a perfect circle, or the circle must continual deform.
Sorry for the length of this. One of these days maybe I'll figure out how to post links without freezing up my POS cheap idiot box. The Geeks won't deal with me without a credit card, like I want some Ukrainian 'freedom fighter' to hack what little I have in the bank so they can default on 150bn they owe the Ruskies. Pewrsonally I think Kerry and McCain should have come home from Nam before they poked their noses in over there. Peace, jrc