〈 Berger | Dillon 〉

If you confine a particle to go through a tiny slit, the more spread you will have in the momentum distribution. Take a photon, as it goes through the slit you will precisely where it is but you won't know the direction it is headed (i.e. it's instantaneous momentum vector)

Make the slit smaller and smaller, the light the resulting interference pattern will grow wider and wider. If you can get both at the same time then you my friend will get a nobel prize

Again, look at how you would measure the interference pattern. I think that one would throw one photon at a time. And for each photon, one would need to know both the slit size and the place where it lands. Effectively measuring both x and p.

No, quantum particles don’t follow definite trajectories.. this is the whole point of the path integral approach. It envisions space as infinitely many infinitesimally small slits stacked one after another.

You can’t say it left the slot with this or that momentum and followed some definite trajectory and work backwards

We can say this only of asymptotic non interacting states, which we do in the LHC

In essence I am not arguing against Heissenbergs principle. I am arguing against applying it to a single event, when it is an expression on ensambles/many events.

But you were just applying the photon scattering to a single event saying you could work backwards and find the momentum