God doesn't play dices

It is a famous phrase of Einstein, but one that has been widely misunderstood.

Good old Albert wasn't expressing his dislike of Quantum Mechanics - he was stating a fact.

Schrödinger's wave function calculations, the way physicists use to  define and make prevision about the probable characteristics of a particle (or any system that can be modelled with quantum mechanics, really... I'll keep using particle as a nickname for "every system etc."), are completely deterministic.

As deterministic as, say,  the movements of gears in a gear train.

You can plot the interactions of said particle through an infinite number of particles and fields, and the final values measured will always respect the probabilities calculated.

There is no loss of information, no probability involved at the wave function level.

Probabilities only come into play when a measure is taken, to verify how things are, not before.

The Copenhagen's interpretation of this fact was that the act of measuring "forces" the particle to acquire a definite state.

In the case of entangled particles - particles whose quantum characteristics have been "synchronised" - you also know, instantly, the state of the "twin" of the particle you just measured.

Even if, in the meanwhile, the twin particle has reached the other side of the universe.

So, if taking a measure "forces" the particle in front of the experimenter, it also forces its sister near Alpha Centauri.

Instantaneously, speed of light as the limit for physical interactions and associated general relativity be damned.

Einstein didn't like this "instantaneous action" at all.

For him it was not physically possible, which in turn meant that the Copenhagen's interpretation of Quantum mechanics was bogus. 

Or, to be more precise,  that it is not really an explanation - just a constatation of how things seems to go, a bit dressed up and not all that well.

He thought that, in the long run, it would have been possible to acquire enough hints on the real nature of the universe, of the real processes that the wave function models statistically (the same way thermodynamics describes statistically the behaviour of an enormous number of atoms, each one acting in a purely mechanical way),  to dispel this and others apparent mysteries.

I think he was right.

Among the alternative interpretations that have been devised, to explain some of the vagaries of quantum mechanics, there are some that say that we exist in a multi-verse.

This could be because we are really living on a 4D (high, wide, long and time) membrane immersed in an universe with many more dimensions, but the details of the actual model can be omitted for what I am going to say.

 If wee live in a multi-verse, this must have at least one spatial dimension more than the ones that we can perceive.

At  least, and that's enough for me (the 'brane is a variant of the string theory that postulates 10 dimensions - other variants prefer 11).

It is then possible that what we see as particles are just the intersection with our dimensionally limited plane of existence of more complex objects, that evolve in dimensions we can not directly see.  

To have an idea of how complicated it is to recognize such an intersection, this is a video of a four dimensional cube sliding through our reality - the changing shape forms that succeed themselves in the same place are, really, projection of a fixed form 4D cube that moves perpendicular to, and through, the observer space.

So, when a measure is taken, the measure DOES NOT "force the particle to take a definite state".

What it really does, is to tell US in WHICH of the enormous number of universes that intersect with that particle WE exist (or, if you prefer the 'branes version of String theory, on which 'brane we do reside).

Knowing the state of a synchronized particle lying at the other side of the universe is, then, just as natural as knowing the position of the Voyager, as the two particles'have just kept moving for inertia (I have a 4 panels comic to draw over this) the same way Earth and the Voyager  have.

It's just the necessary result of  a fully deterministic process.