  Recently the physical mechanism for geometric phase in optics has been
elucidated in terms of the angular momentum holonomy proposed in 1992. Aharonov
and Kaufherr (PRL, 92, 070404, 2004) revisit the Aharonov-Bohm effect, and
propose non-local exchange of a conserved, gauge invariant quantity that
changes the modular momentum of the particle that is responsible for the AB
phase shift. We suggest that the net angular momentum shifts proposed for GP
may be analogous to the shift in the modulus momentum for the AB effect. At a
single photon or electron level such non-trivial, geometric effects seem to
hint at a new physics.
