Most things like to occupy regions of lower potential. So the probability amplitude should be higher in a region of lower potential. I denote the potential by V. However, we also know that the kinetic energy of a particle is given by E-V - the bigger this E-V difference (the lower the V basically...

If the galactic mass is rotating around a central supermassive black hole, should their spin axis not be the same, just as we would obtain for the rotation of a star and its planets ?

Do we observe dots on a position detector like in the double slit experiment? I doubt that because the double slit experiment is non-relativistic QM, and so a "position measurement" is defined. However, there's no "particle position" operator in Quantum Field Theory. In ordinary QM, I visualised ...