Question

One Dirac fermion built from two real fermions with different velocities?

Answer 1

This is not in general a reasonable thing to expect to be able to do. In SR, these coordinate transformations will only work locally. The coordinates can only be extended to a distance x∼c2/a away from the observer's world-line, where a is the acceleration of the observer. At greater distances, the coordinate transformation isn't one-to-one. In GR, coordinate systems do not describe observers

Answer 2

The GR movement of the particle makes the effect of the total unity of the full unity.