Many Worlds Theory of Quatum Physics

[mikeymike99]

Let's suppose a QP experiment has two outcomes. Does the MWT say that the two possible outcomes are 'farmed out' to two pre-existing parallel universes. Or is it that this experiment results in the creation of one other brand new universe?

[jake-the-peg]

It's effectively creating a superimposed universe each time.

The Wikipedia entry is quite involved but is here:

http://en.wikipedia.org/wiki/Many_worlds_inter pretation

[mikeymike99]

Thanks for that. I've looked through the article and still not really sure. For example:
"The accepted terminology is somewhat misleading because it is incorrect to regard the universe as splitting at certain times; at any given instant there is one state in one universe." Which I don't quite understand but it seems to go against new-universe creation.

[jake-the-peg]

Quantum mechanics really will mess with your brain and it's really importantant that you don't approach it with pre-conceived notions of how things should work.

I tend to think of it as the universe splitting rather like an amoeba rather than a new creation.


If you take the classic 2 slit experiment where you send a particle through the 2 slits.

Quantum mechanics will tell you what the probability of getting a particle at a particular place is by superimposing both routes and dealing with the whole.

It does not tell you about what is actually happening to a particular particle in the experiment.

The various interpretations attempt to explain 'what is happening'. However this tends to be a philisophical argument because generally speaking there is no way to actuall test which is right and which is wrong.

In the Copenhagen interpretation questions like what is happening are essentially meaningless. If you attempt to find out the so called wavefunction that describes all the possibilities 'collapses' and one possibility becomes 'reality'. In the Many Worlds Interpretation when the wavefunction collapses one possibility becomes reality in one universe and one possibility becomes reality in another.

Exactly what causes this collapse is called the "measurement problem" http://en.wikipedia.org/wiki/Measurement_probl em

Sometimes it helps to think in terms of "flatland" where squares and triangles do experiments in a 2D world unaware of the 3rd dimension into which their experiments extend.

Personally though I find it hard to get excited about these interpretations until there's a test that we can do to see if one is right and another wrong - then it stops being philosophy and starts being science

[mikeymike99]

Again thanks...it seems the best thing to do is not try to work out what's going on behind the scenes and just accept the results - at least this way will help me sleep sounder at night!