Local Space-Time Curvature Effects on Quantum Orbital Angular Momentum

This paper claims that local spacetime curvature can nontrivially contribute to the properties of orbital angular momentum in quantum mechanics. Of key importance is the demonstration that an extended orbital angular momentum operator due to gravitation can identify the existence of orbital states with half-integer projection quantum numbers m along the axis of quantization, while still preserving integer-valued orbital quantum numbers l for a simply connected topology. The consequences of this possibility are explored in depth, noting that the half-integer m states vanish as required when the locally curved spacetime reduces to a flat spacetime, fully recovering all established properties of orbital angular momentum in this limit. In particular, it is shown that a minimum orbital number of l = 2 is necessary for the gravitational interaction to appear within this context, in perfect correspondence with the spin-2 nature of linearized general relativity.