Thanks for your comment, Lenka.
You are absolutely right in both points. I’m aware that it doesn’t get clear the way I wrote it back then.
I used the terms force carrier or boson to speak about interactions, but it’s true that not all interactions have a massless carrier (so not all interactions take place at the speed of light). Maybe I should have used the terms photon, gluon, graviton and/or massless quanta to be more specific about that. I’ll check the text and maybe edit it a bit to be more precise.
About the other topic (how matter particles can imprint an interference pattern in a double slit experiment), it is also true that I don’t speak much about it, but the way I see it is that, in reality, every interaction that happens in the universe (everything underlying reality) happens at the speed of light in spacetime (so, “instantly outside spacetime”, at the same time), but some complex matter structures such the Z and W bosons, the electron and other matter particles are simple enough to conserve their “material identity” and behaviour even on quantum experiments.
I see these matter particles as kind of resilient structures of fields and interactions. They are able to show some amount of entanglement or quantum behaviour because, although they don’t travel at the speed of light, the fields that define them do.
In fact, my very first comment on Medium was on your great article about how everything is “travelling” at the speed of light in spacetime!
