# You may not be alone

f you think of yourself as unique, think again. The days when physicists could ignore the concept of parallel universes may have come to an end. If that doesn't send a shudder down your spine, think of it this way: our world is just one of many. You are just one version of many.

David Deutsch at the University of Oxford and colleagues have shown that key equations of quantum mechanics arise from the mathematics of parallel universes. "This work will go down as one of the most important developments in the history of science," says Andy Albrecht, a physicist at the University of California at Davis. In one parallel universe, at least, it will - whether it does in our one remains to be seen.

The "many worlds" interpretation of quantum mechanics was proposed 50 years ago by Hugh Everett, a graduate student at Princeton University

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#1The sun alone will create millions of universes/second.

And you guys make fun of my God belief?

#2Wait, so, does that mean they have proved it true, or just possible? If they have proved it true, it should be on the front cover of every paper on Earth, since we've been searching for this for decades.

On the other hand, I never understood how to reconcile multiverse and MWI. Does that mean that each seperate universe has an infinite number of Carbon copies?

"Physical reality” isn’t some arbitrary demarcation. It is defined in terms of what we can systematically investigate, directly or not, by means of our senses. It is preposterous to assert that the process of systematic scientific reasoning arbitrarily excludes “non-physical explanations” because the very notion of “non-physical explanation” is contradictory.

-Me

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#3Mathematically possible, once one goes beyond this it's down to interpretation, so I wouldn't go as far as saying mathematically proven as yet, and it's highly possible that it shall never be proven

Thing is the infinite, once an infinite is introduced into an equation it becomes suspect, as one cannot prove an infinite

So one might speculates about an infinite amount of universes tied on the quantum level or an infinite amount of universes not tied on the quantum level

Or just that it is mathematically possible, and that mathematics is an inadequate way of describing our universe

There is some funky stuff going on in quantum physics at the mo this is one possible explanation for that non-intuitive funky stuff

#4deludedgod wrote:unfortunatly, it looks like you can't view the full article without subscribing. i'd love to know more about this. does anyone else have links to full articles?

#5try this

#6Rev_Devilin wrote:from the above article:

Dr Deutsch showed mathematically that the bush-like branching structure created by the universe splitting into parallel versions of itself can explain the probabilistic nature of quantum outcomes. This work was attacked but it has now had rigorous confirmation by David Wallace and Simon Saunders, also at Oxford.

-----------Dr Deutsch added that the work addresses a three-century-old problem with the idea of probability itself, described by one philosopher, Prof David Papineu, as a scandal. "We didn't really know what probability means," said Dr Deutsch.

There's a convention that it's rational to treat it for most purposes as if we knew it was going to happen even though we actually know it need not. But this does not capture the reality, not least the 0.1 per cent chance something will not happen.

...

Thanks Rev.

edit: Deutsch at arXiv

http://xxx.lanl.gov/ftp/quant-ph/papers/0104/0104033.pdf

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#7Eloise wrote:This may be of some assistance source

The Everett, or many-worlds, interpretation gives a different account of quantum measurement. Indeterminism enters the 'textbook' story at the point of wavefunction collapse: when the measurement is performed, the wavefunction is supposed to collapse (indeterministically) into one or the other eigenstate of the observable being measured. But the many-worlds interpretation denies that collapse occurs. Instead, according to the many-worlds interpretation, when the measurement is performed, the apparatus, and the observer, and the laboratory, and indeed the entire world, will split into two copies, or 'branches'. There will be one branch on which the spin-up outcome occurs (and a future copy of the observer records spin-up), and there will be another branch on which spin-down occurs (and a future copy of the observer records spin-down).

#8Had a semi sleepless night thinking about this, so I'm quite tired I hope this makes sense

It is false, it isn't true, it's bogus

The universe would run out of energy extremely quickly if it was true

Universes don't come free they require energy, if you divide the energy from this universe to create every possible alternative then you run out of energy extremely quickly

So this would need to be powered externally in fact every atom in your body would need to be powered externally, and there's no evidence of this happening

Could somebody give me a time and date for this

#9Agreed. I always had a very large number of objections to Everett's interpratation.

Now, I am extremely sympathetic towards Cosmological Multiverse theory, of seperate universes which bud off each other and whose only connection to each other is via Einsten-Rosen bridges. It ties in with string theory, brane theory, Inflation and the Anthropic Principle.

On the other hand, Everett MWI is almost impossible to get one's head around. The concept of decoherence. Firstly, how on Earth does the quantum event in question generate a new universe in which the divergence occurs. Does it simply spring into existence from that point in question? Surely that is ludicrous!

Second, Quantum Mechanicians always talk about Everett as though MWI could have macroscopic influences, such as, for example, "a universe in which Hitler won the war", or "a universe where Troy did not fall" or "a universe where Everett's theory is more appreciated than in this universe" (to use the above example).

I could never follow this line of thought. If we examine divergence winding the clock back to the Big Bang, the number of branches must surely have been utterly infinite, and continue to be infinite, as Probability waves diverge, since the number of quantum events is so utterly vast. Andan infnite number of universes are spawning from quantum universes which were generated from the previous universe, and so on. The number of universes, if we assume one universe at the moment of creation, would explode hyperbolically. This is silly enough as it is, but the real problem I had, as I said, was this idea that single tiny quantum divergences can alter macroscopic events such that they can influence human history? Surely that is ridiculous. Quantum effects do not occur past the subatomic level. A single tiny quantum event would have no relevance on, say, the course of human history, because at the scales of reality which determine these things are determinstic not quantum. And since divergences are caused by single quantum events, there can be no cumulation of alterations by which any serious change to any macroscopic level event may occur. So why do we speak as though it could?

thenwe need to take into account that from each universe which decoheres from its parent,I cannot see how "A divergence where the electron appears at Peak X of the probability wave instead of Peak Y" can translate into "A universe where Hitler won the war".

EDIT: If there are any physicists who wish to explain how this works, go nuts with the jargon and technical terms, I studied physics, but I cannot recall having ever studied how quantum decoherence may cumulate into macroscopic events.

PS I support Wheeler's QM, Guth's Inflation and Kaku-Smolin Cosmology

"Physical reality” isn’t some arbitrary demarcation. It is defined in terms of what we can systematically investigate, directly or not, by means of our senses. It is preposterous to assert that the process of systematic scientific reasoning arbitrarily excludes “non-physical explanations” because the very notion of “non-physical explanation” is contradictory.

-Me

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