Mathmatically, why are parallel universes even theorized?

[Albertgauss]

Hi all,

What is the Hamiltonian or main equation, that if you solve it, parallel universes are predicted?

For example, the Dirac equation, if solved, predicts the existence of anti-particles. If You solve Maxwell's Equations, you predict there should be E & M waves. Solving certain aspects of the Einstein's General Relativity Tensor Equations predicts black holes.

But I have not seen any hamiltonian, Lagrangian, etc. that if you solve them, parallel universes (of any kind) are predicted. Can someone guide me to such a reference (book, webpage, etc) where some basic parallel universe solutions are worked out.

Thanks,
Albert Gauss

 

[Chronos]

Parallel universes have historically not enjoyed much in the way of rigorous mathematical support. Here is one of the better known efforts: The Structure of the Multiverse, http://arxiv.org/abs/quant-ph/0104033. The paper did not, however, seem to generate a great deal of interest. It has not been cited to date.

 

[sheaf]

Nomura argues that the quantum multiverse can be identified in some sense with the pocket universes of eternal inflation.

 

[kith]

What is the Hamiltonian or main equation, that if you solve it, parallel universes are predicted?

Parallel universes are part of an interpretation of the QM formalism (called the Many Worlds interpretation). So these worlds are not a prediction in the sense of your other examples and can't be distinguished from the single universe view of other interpretations.

The basic idea of Many Worlds is to question the collapse of the wavefunction by stating that all possible outcomes are realiszed in different, non-interacting worlds. So in principle, you see the potential parallel universes in every wavefunction prior to measurement. Mathematically, such an interpretation is justified by decoherence, which occurs because of the interaction between the system and the measurement apparatus. Here's a review article by Maximilian Schlosshauer: http://arxiv.org/abs/quantph/0312059.

 

[mathman]

There are two (at least) distinct concepts under the description of multiverse.
1) Quantum theory - all possible outcomes of experiments occur in parallel universes.
2a) Our universe is a bubble in a collection of universes - the big bang was a local event leading to the bubble.
2b) M theory - brane collision led to the big bang.

The main objection to any of these is they are (at least for now) untestable.

 

[julian]

I think the idea of relational quantum mechanics makes more sense than parallel universes...Lee Smolin book "Three roads to quantum gravity"..."Many of us believe that this as a definite step in the right direction. Rather than trying to make sense of metaphysical statements about their being many universes - many realities - within one solution to the theory of quantum cosmology, we are constructing a pluralistic version of quantum cosmology in which there is one universe. That the universe has, however many different mathematical descriptions, each corresponding to what each observer can see when we look around them. Each incomplete, because no observer can see the whole universe. Each observer, for example, excludes themselves from the world they describe. But when two observers ask the same question, they must agree."..."One universe, seen by many observers, rather than many universes, seen by one mythical observer outside the universe"

For math rigour see work of Isham (topos theory), Crane, Rovelli...

 

[julian]

Multiverses are a different idea and I think there is some theoretical physical reasoning for their production.