is called the action of the path,
and to each path we define an action,Probability Wave Dispersion
The function is called the action of the path,
and to each path we define an action,
(3)
It is weighted against Planck’s constant, which also has units of action per radian.
In a Schwarzschild space-time the metric
component 
is,
(4)
and the action can be written as,
(5)
It is immediately evident how the curved Schwarzschild metric affects the propagator by adding a phase shift to the time evolution,
(6)
This is Probability Wave Dispersion! It is the result of the gravitational field acting on the wave function of the free electron.