Quantum Mechanics, Time and the Multiple Universes

[J]

I've currently been reading Anathem by Neal Stephenson and it has raised a lot of questions in my mind about the divergence of time-lines and reality. I'm not a scientist or philosopher in name, but these kinds of topics in the scientific and philosophical sense really really intrigue me as I'm certain that other Nerdfighters have the same tendency.

The Schrödinger's cat thought experiment states that the cat at one point is simultaneously alive and dead and this is due to quantum mechanics. One supposition of Neal's in Anathem is that at the point where the cat is both dead and alive diverges into two separate time-lines. Now, if that were to be true there would be an almost infinite number of universes diverging constantly. Would this be a possibility? It is hard to imagine it could be, but if you are aware of Buddhist beliefs, you might know similar thoughts.

I know I am trying to tackle ideas that are much bigger and incomprehensible to many, but it would be nice to have a discussion about such things here. Please, if you have ever been interested in or questioned reality and the possibility of multiple universes post your thoughts here. I know there will be a lot of divergence of opinion and 'knowledge', so let's try to keep this to a minimum of mud slinging.

[J]

If at every moment every possible outcome diverges into separate universes and we consciously experience one single time-line, would it be plausible to state that our lives that we experience are somehow created by us and that our paths that we take are somehow meaningful and there for us to learn from?

This is from a Buddhist point of view that we really are here to attain self knowledge and we are here to suffer to learn, but it can be applied to non-Buddhists as well.

[Leviathan]

I would recommend reading about determinism and indeterminism on this thought. One of the main proponents of 'free will' provided by quantum mechanics stems from the Hiesenburg uncertanty principal. This states that, at a subatomic level, electrons exist at an infinate number of possible locations within thier orbitals, and that only observation can determine the position of the electrons for that instant in time, bringing them from a quantum state to a physical one. Some argue that, because of this, infinate number of universes, along with free will, must exist.

Food for thought..

[J]

It's interesting that you bring up free will, determinism and indeterminism as our minds are like the electrons existing in an infinite number of possible locations. We have in our decision making process a large number of plausible possibilities and everything inbetween, which in turn leads to the idea of 'free will'. Any impossible/improbable ideas we have are filtered out, which narrows our thought processes greatly. But as an electron is influenced by observation alone, so are we.

I'll have to read more on determinism and indertminism as I just skimmed the wikis. :P
Thank you for introducing more of this to me though.

[Dylan Patterson]

Sounds to me like your talking about the Multiverse. The Multiverse is a theoretical structure that holds multiple universes, one being our own, that are very similar with key historical difference. For example in one universe Al Gore was elected president in 2000, in another he was elected in 2008, and in yet another he is the current president of Kenya. I personally like this theory because it completely demolishes the line between what can exist and what does exist. Everything that can exist does exist. If this is in fact what you are looking for I suggest you research a man named Max Tegmark.

[Melissa]

Hey, there's a Dianna Wynne Jones book about that! Well, not directly about that. But the Crestomanci books sort of deal with the whole multi-verse thing, don't they?

It's an idea I've thought about all my life, believe it or not. I've always wondered what it would be like if every single decision made a new universe. Then I wonder if ALL decisions would make new universes, or if only the important decisions would (responding to this thread versus a decision to sign a treaty). If really, truly, EVERY decision made a new universe, then there would be a universe where I decided to leave out a letter in a random word, or leave out a random word entirely, and that has always seemed much too frivolous. What would the purpose of that be? However, if it was a life or death situation, I could see how those decisions might create new universes. In other words, it only makes sense (to me, at least) for the decisions that would change the universe, to make a new one.

[Astroskylark]

The Schrödinger's cat experiment attempts to explain the phenomenon of quantum state, and illustrates how it is possible for an object to have a mixed quantum state. In reality, the practical application of quantum state can be found when scientists use particle accerlators to move particles at very high speeds in a very precise matter. When a certain elementary particle is 'fired' at a buckminsterfullerene molecule, and manages to get inside it, the 'spin', or quantum state, of the buckminsterfullerene molecule is up and down at the same time. This simply means that the spin, if checked, has an equal probability of being up as being down. Of course, once the spin is checked, it is determined whether it is up or down, and the quantum state returns to normal.

This does not require the divergence of a separate universe, as it is entirely possible for an object to have a mixed quantum state. It is however, quite possible that multiple universes exist. In fact, there could be an infinite number of universes that exist simultaneously, and in each one, a single variable is changed. For example, in one such universe, Hitler never lived, or was killed as a child, or died before he had the opportunity to wreak havoc on our world. In another universe, humanity never evolved beyond tree-dwelling hominids, and in yet another universe, life on Earth never arose at all. Of course, if one were to observe these universes, a change that occurred in the distant past would be more noticeable then a change that occurred yesterday.

And on the problem of diverging universes: Say time travel were possible, or it was possible to in some way manipulate time. It is speculated that, if one were to go back in the past, their very presence would disturb the natural order of things so much that they would be automatically thrown into a parallel universe. Another theory that is more liberal states that a time traveler would be thrown into another universe only if they changed something. One of the more well known time travel theories is the Grandfather Theory, which speculates that if you were to go back in time and kill your Grandfather before he met your Grandmother and had your mother/farther, you would create a paradox that would result in the time traveler being thrown into a parallel universe. (As you may have noticed, most of these theories result in the time traveler being thrown into a parallel universe.)

And of course, reality and time are relative, and time generally requires something capable of perceiving it to exist ( Similar to "If a tree falls in a forest, does it make a sound?" ).

[Astroskylark]

And there is a concept called infinite regression (present in the Buddhist religion?), which states that within every atom, there is a smaller universe, containing a finite number of atoms which in turn contain yet another smaller universe. The concept extends itself to say that our universe is just one of those universes that exist in an atom in a much larger universe. This pattern extends in each direction infinitely, and is very intriguing, and would result in an infinite number of universes as well.

The Multi-universe theory differs in that it allows for infinite universes outside of our own, not within our universe.

In the cyclic model of our own universe, which states that our universe will exist for a finite number of years before contracting (it is currently expanding) and experiencing a 'Big Crunch' (the opposite of a Big Bang), followed by another Big Bang, which will, eventually be followed by a Big Crunch. This cycle repeats indefinitely and will, given an infinite amount of time, result in an infinite number of universes that exist separately and consecutively.

[M. I. Sirius]

It's an important clue to SOMETHING that multiple inconsistent timelines can coexist on the nano level. But that doesn't imply that they can exist - or coexist - on a cosmic scale. Think of the energy required to create (or recreate) an entire universe every time there's a branching, along with a separate cosmos-size space so the universes don't interact. Where does that all that energy come from?

And consider that branching into different futures should be continuous - every time a photon is created with up-spin rather than down-spin.

Not being a scientist, I would guess that there's a (very small) upper limit to the the duration of concurrent incompatible timelines, sort of like the upper limit on Heisenberg uncertainty.

[thad]

The paper listed below is rather technical, but it gets to the core of a lot of what you are saying. Essentially, that we also have to look at the storage of information about the state of the Universe when considering the flow of time/entropy.

http://arxiv.org/ftp/cond-mat/papers/0501/0501014.pdf

It was published in the journal "Entropy 2004"; I am uncertain whether this is a peer-reviewed journal.