Everett's interpretation of QM - does the world actually branch, physically?

Question

Under Everett's interpretation I understand the key notion is that every quantum possibility is physically realized in its own universe, such that any one universe only contains any one physical realization stemming from the "same" parent measurement. I've also understood that it's popular to say that, under this interpretation, the physical world(s) branch out - creating a tree - based on every such possibility.

But, physically speaking, if we take this branching approach naively at face value - are we supposed to understand that from any given state where you have X possible outcomes, what is now 1 physically real world, turns into X physically real worlds (one for each possibility)?

I see this perpetuated all over the place - that X and Y possibilities exist in their own, physically distinct universes, and that this removes some problems in Copenhagen or simplifies some of them. But it's also very confusing, because if that is the case, how do we explain this cloning-the-universe-up-until-this-point into however many possibilities there were? Where does that energy come from? Not to mention - how is it possible to copy all the information of an entire universe in an instant (without violating a bunch of physical laws in the existing universe)?

So - is it really as simple as this answer says; "it is just mathematics"? So that when the many-worlds interpretation says that every possibility is physically realized, you'd think of it in the sense that is to some degree analogical to how you'd think of the electron physically realizing all its possible paths in the double-slit experiment?

Or does the interpretation claim that there are actually physically real and distinct worlds - universes - for each possible outcome? As in, there actually exists a space-time (even if it's inaccessible to us) that is identical to its twin space-time(s) with the only exception being the outcome of that particular measurement? If that is the case, how do proponents of the MWI resolve the problems I posed earlier about information-copying?

Answer 1

Everett's "worlds" are as you described: "analogical to how you'd think of the electron physically realizing all its possible paths in the double-slit experiment". The worlds are not physically distinct and separate. They are coexisting, superimposed probability distributions.

What distinguishes one such world from another is mutual exclusivity within the global probability distribution that encompasses all of the "worlds": "In this set of worlds, the electron was found to have taken the left slit; in that set of worlds, it was found to have taken the right slit; while in all the other worlds it was found to have passed through both slits." This principle extrapolates to Schroedinger's cat, and to all the other consequences of Everett's interpretation.

Answer 2

Yes . .. ..In a quantum computer where collapse does NOT take place on a superposition , we are --as a matter of fact-- experiencing branchification of world/universe into event-making sub-branches where up-or-down symbolization no longer is restricted to one quantum . There must be "quantA" involved to make it possible for interference taking place in , say , a multiple-term's equation so that the intended equation might be solvable with its so many terms only thru a QUANTUM computer and NOT by an ordinary one .So sharp a division about what appears to be a reasonably well-defined question cannot maintain coming together of two ( or more ) 3-D worlds until and unless there are an infinite number of universes, each with its own parameters, its own structure. . . . ... yeah : Physically/Physicalistically . .. .. It is NOT the observer’s consciousness that “forks” or “splits,” because only those subspaces of Hilbert space describing definite macroscopic measurement results satisfy psychological conditions for supporting a unified consciousness. The ONLY other option would be to totally deny any interference and any resulting inference .