Thanks folks, I think I'm getting there, one step at a time, but I'm struggling with this bit as well.

Our measurement of the electron being at x equals the ‘branch’ Bx coming out of its interference with all other branches Bx’ of the quantum universe, in each of which the electron is in another place x’.

Here the author is referencing another potential model of reality that is also currently consistent with Quantum Mechanics. In this model of reality time isn't a string of single events stretching from past to future. Instead every time an event happens every possible outcome happens but a human can only ever observe one. Instead of imagining time as a line it instead becomes more tree like with every possible outcome of an event spawning a new line or 'branch'.

You could think of this model as saying that when a particle is acting like it is delocalized that is really just a bunch of possible universes (branches) interacting with each other and in each universe (branch) the particle is in only one place. As long as you don't try measure the location of the particle exactly all those universes (branches) are free to keep interacting but as soon as you make that measurement you essentially pick a universe (branch). In this model the only way for an electron to be bound to an atom is for the electron to be delocalized via this interaction of many universes (branches) interfering with each other. Once you pick a universe (branch) via an observation the interactions between universes (branches) cease and the electron can no longer be bound to the atom.

I am not sure if this fits here if not maybe we could start another thread.

One-electron universe

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/One-electron_universeThe one-electron universe postulate, proposed by John Wheeler in a telephone call to Richard Feynman in the spring of 1940, states that all electrons and positrons are actually manifestations of a single entity moving backwards and forwards in time. According to Feynman:

I received a telephone call one day at the graduate college at Princeton from Professor Wheeler, in which he said, "Feynman, I know why all electrons have the same charge and the same mass" "Why?" "Because, they are all the same electron!"[1]

The idea is based on the world lines traced out across spacetime by every electron. Rather than have myriad such lines, Wheeler suggested that they could all be parts of one single line like a huge tangled knot, traced out by the one electron. Any given moment in time is represented by a slice across spacetime, and would meet the knotted line a great many times. Each such meeting point represents a real electron at that moment.