Other Universe

[Mr. Moonlight]

Are multiple universes a consequence of a standard theory of the universe or a more complex harder to prove theory i.e. the multiverse theory. And also does anyone know what the possiblity is of matter arranging itself in such a way as to be the same or at least very similar to our own universe. Thank you.

[Realitycheck]

I think all of the talk about multiverses is just a result of people trying to dream up their own news. Kind of irresponsible if you ask me, though it seems like more of a fad than anything. Has there been anyone other than Kaku that has supported the idea and to what extent did he support it? I can't imagine it being anything more than bold speculation out of anybody's mouth, so why is the idea so popular? Whats the likelihood of a Big Bang happening in each bubble? Or do we just throw away all of that BB data? That's really what it boils down to, right? Multiverse equals no Big Bang? So a different model for our universe needs to be offered, but I thought our BB model was pretty well established.

Edited August 22, 2011 by Realitycheck

[khaled]

I believe that the universe is only what it is, and time-dimension is a fabrication to show progress

.. and that time travel is a one-direction operator applied to the degree of time-flow observation

 

time-flow is a continuous line, where one's observation is periodic over that line ...

[spacelike]

Not entirely.

 

The orthodox interpretation of quantum mechanics basically requires the existence of many worlds.

However this isn't the "multiple universes" you are probably talking about because these 'many worlds' are not independent, they would branch from our universe at every instant.

 

If we look at simply the amount of different possible initial configurations for the big bang alone, that could easily give rise to essentially an infinite amount of different realities. As far as we know it may even have been possible for the result to yield different laws of physics in some of these realities.

 

So, it really is a short leap from there to "multiple universes"... I think what you have in mind would be universes that pop into existence independently without a common origin.

 

But is this really so far-fetched now? It seems that time and time again in physics we realize that unless there is a specific law to prevent something from happening it almost always happens, or we eventually find a law prohibiting it.

 

As it stands, we know one universe was able to somehow form, so really in some respects it would be more amazing if this was the only universe.

Just because the idea of multiple universes seems more strange, or more foreign, or more difficult to digest, does not in any way imply that it is less likely.

 

Also, who said the existence of multiple universes would mean we would have no big bang? You could definitely still have a big bang with multiple universes.

Edited September 7, 2011 by spacelike

[mathematic]

 

 

The orthodox interpretation of quantum mechanics basically requires the existence of many worlds.

 

This is an interpretation. I doubt if it is orthodox, rather it is an interesting idea that some take seriously as a possibility.

[spacelike]

This is an interpretation. I doubt if it is orthodox, rather it is an interesting idea that some take seriously as a possibility.

 

I didn't mean it as a separate interpretation and that it was also "orthodox". I was only referring to the Copenhagen Interpretation which is also known as "the orthodox interpretation" it's just what it is called.

But it also happens to be the most popular interpretation.

 

So what I meant was copenhagen interpretation implies many worlds.

 

But I'm glad you brought that up actually because I may have said that too strongly.. Personally I don't see how it can be any other way, but I can't say for sure if other possibilities exist or not.

 

 

But in any case, I can say that the concept of many worlds can be shown to be logically consistent with the copenhagen interpretation. I should have just worded it that way in the first place.

Edited September 8, 2011 by spacelike

[mathematic]

Many worlds is consistent with Copenhagen, but Copenhagen doesn't require many worlds.

[khaled]

Not entirely.

 

The orthodox interpretation of quantum mechanics basically requires the existence of many worlds.

However this isn't the "multiple universes" you are probably talking about because these 'many worlds' are not independent, they would branch from our universe at every instant.

 

If we look at simply the amount of different possible initial configurations for the big bang alone, that could easily give rise to essentially an infinite amount of different realities. As far as we know it may even have been possible for the result to yield different laws of physics in some of these realities.

 

So, it really is a short leap from there to "multiple universes"... I think what you have in mind would be universes that pop into existence independently without a common origin.

 

But is this really so far-fetched now? It seems that time and time again in physics we realize that unless there is a specific law to prevent something from happening it almost always happens, or we eventually find a law prohibiting it.

 

As it stands, we know one universe was able to somehow form, so really in some respects it would be more amazing if this was the only universe.

Just because the idea of multiple universes seems more strange, or more foreign, or more difficult to digest, does not in any way imply that it is less likely.

 

Also, who said the existence of multiple universes would mean we would have no big bang? You could definitely still have a big bang with multiple universes.

 

there is only 1 universe, multiple universes is the superposition of the universe, and it's a paradox, we don't talk about "orthodox" which is related to Christianity religion ...

 

I suggest you read about basics of Quantum Mechanics, the superposition, and the Uncertainty,

[spacelike]

there is only 1 universe, multiple universes is the superposition of the universe, and it's a paradox, we don't talk about "orthodox" which is related to Christianity religion ...

 

I suggest you read about basics of Quantum Mechanics, the superposition, and the Uncertainty,

 

I didn't make up "orthodox" that is straight out of David J. Griffiths book on quantum mechanics as an alternative name for the "Copenhagen interpretation". I care nothing for religion, but if you say it has to do with christianity than thank you I'll try and avoid that particular name for it in the future, but I did not make it up.. Copenhagen sounds better anyway.

 

I am familiar with basic quantum mechanics.

I am aware that the mathematics of quantum mechanics does not lead to any such claims. It is only from thinking about different interpretations of quantum mechanics that leads to things like many worlds.

 

But don't tell me to read basic quantum mechanics as if I don't know any physics and I am actually just making all of this up based on something I read on wikipedia or something.

I am not saying this is what quantum mechanics tells us, I am just putting forth one possible interpretation that supports what OP was asking. Furthermore basically everything I said has also been stated by Stephen Hawking.

I am unbiased though, I don't care one way or another and I keep an open mind to all possibilities, but one cannot deny that many worlds does not only not violate any laws or theories, but is actually supported by some, and therefore should not just be dismissed by any serious physicist as far as I know.

I'm just an undergraduate so perhaps my information is incomplete but this is the best I can say on the matter with the information I have.

Edited September 13, 2011 by spacelike

[khaled]

I didn't make up "orthodox" that is straight out of David J. Griffiths book on quantum mechanics as an alternative name for the "Copenhagen interpretation". I care nothing for religion, but if you say it has to do with christianity than thank you I'll try and avoid that particular name for it in the future, but I did not make it up.. Copenhagen sounds better anyway.

 

I am familiar with basic quantum mechanics.

I am aware that the mathematics of quantum mechanics does not lead to any such claims. It is only from thinking about different interpretations of quantum mechanics that leads to things like many worlds.

 

But don't tell me to read basic quantum mechanics as if I don't know any physics and I am actually just making all of this up based on something I read on wikipedia or something.

I am not saying this is what quantum mechanics tells us, I am just putting forth one possible interpretation that supports what OP was asking. Furthermore basically everything I said has also been stated by Stephen Hawking.

I am unbiased though, I don't care one way or another and I keep an open mind to all possibilities, but one cannot deny that many worlds does not only not violate any laws or theories, but is actually supported by some, and therefore should not just be dismissed by any serious physicist as far as I know.

I'm just an undergraduate so perhaps my information is incomplete but this is the best I can say on the matter with the information I have.

 

I simply told you to read Q.M basics, because your speech earlier sound like you don't understand reality of Q.M,

in Q.M, there is only 1 universe, 1 cat, 1 object .. but with no observation that object can change move into a new state as time progress,

and if we observe the state, we get the reality of the object in time, otherwise we extend current superposition to contain all possible states.

 

Sorry for the assumption,

[spacelike]

I simply told you to read Q.M basics, because your speech earlier sound like you don't understand reality of Q.M,

in Q.M, there is only 1 universe, 1 cat, 1 object .. but with no observation that object can change move into a new state as time progress,

and if we observe the state, we get the reality of the object in time, otherwise we extend current superposition to contain all possible states.

 

Sorry for the assumption,

 

no problem.

 

Also, I don't really care too much for the interpretations anyway, so correct me if I'm wrong. But I don't think the many worlds thing is contrary to what you just said because I think the only reason the idea comes into the scene is because of the wave function collapse. As far as the evolution of the wavefunction with time is concerned there is no need for many worlds, but it is the collapse after a measurement that brings all of these things into question.

But QM doesn't really say exactly what happens at this point, so it kind of seems that it is completely open to interpretation. I know mathematically we basically just write the new wavefunction as the eigenstate representing the value that was observed and see how it evolves from there with time again. But the thing is it's random which of the states it ends up collapsing to, so the idea is that the universe doesn't actually just somehow pick one possibility and that's it, but rather that all exist

 

It's a bit outside of this discussion but I think the strongest argument for it is when you try and figure out how the Copenhagen interpretation would work in different perspectives.

Say for example the Schrodinger's Cat thought experiment, replace the cat with a person if you like and then ask, what does the person observe?

We observe him as a definite state which is a superposition of the two eigenstates "alive" and "dead".

But the person is constantly observing himself/herself so he/she is already collapsed to one of those eigenstates.

 

The only thing that seems to be able to save the Copenhagen Interpretation if we go on assuming that an "observation" or measurement is what collapses the wavefunction, is to introduce many worlds.

That was my understanding and that was sort of what I was trying to say in my original post.

 

But of course there could be other possibilities or explanations, but that's the argument in favor of many worlds I am most familiar with. There is probably just as many against it though.

Edited September 14, 2011 by spacelike

[khaled]

But of course there could be other possibilities or explanations, but that's the argument in favor of many worlds I am most familiar with. There is probably just as many against it though.

 

There are different interpretations, take for example Schrodinger's Cat .. when we start the experiment, after a while without observing the cat inside,

 

we have two cats, one cat was alive and became dead, and the another was alive and still alive .. it's just like that the cat have a probability decision

tree, where since we don't know which branch it took, we have to assume that we have all those versions in parallel at the same time.

 

another interpretation is that using the superposition, for example the cat have a probability of dying by 1/4, and remaining alive by 3/4 ..

so in Time(0) we have a Cat with (1,0) for (alive,dead) superposition, in Time(1) we have (3/4, 1/4) that is interpreted

like this "the cat is 25% dead, and 75% alive" ...

 

.. thanks

Edited September 16, 2011 by khaled

[spacelike]

But are those really different?

The first one considers things from the cats perspective and the second one considers things only from our perspective.

 

If you try and use the second one only and ask how do things appear from the cats side, don't you get again the same result as the first one? So I think they actually go together. One way I think of it is instead of like you said in the first one where there is only 2 cats, what if there are an infinite amount of cats and due to the probability (25% dead, 75% alive) 25% of the cats end up alive and 75% dead, which is equivalent to saying any one of those cats has a 25% chance of being in the "alive branch" and 75% in the "dead branch".

 

The thing is if you only have one cat, then we know the cat observes itself and knows if it is alive or dead. We also know that according to our perspective the cat must have a 25% chance of living and a 75% chance of dying.

However, the copenhagen interpretaion would say that this probability means that (even though let's say the cat observes itself to be alive) there is literally still a chance that we would observe a dead cat.

 

Since these are independent observations, so considering all possible outcomes of both we see that technically it is a possibility that the cat observes itself to be alive and we observe it to be dead at the same instant. Or vice versa.

So different perspectives would contradict each other, but can be reconciled if you consider that there are multiple cats like you were saying, and that is just the idea of many worlds isn't it?

So 25% of the cats would end up in the "alive branch" in which we also measure the cat to be alive and the cat and the experimenters versions of reality are the same.

and 75% of the cats end up in the "dead branch" in which we also measure the cat to be dead.

 

So if there are many worlds like this then the cat and the human will always agree on the outcome (alive or dead) even though each is supposed to get a result independent of what the other gets.

Edited September 16, 2011 by spacelike

[khaled]

But are those really different?

 

Yes, you see in the first interpretation, we have N parallel objects at first that increase exponentially with time .. in the second, we only have 1 object, which have N states

paired with their probabilities [math]P_i[/math], where [math]\sum_{i=1}^{N} P_i = 1.0[/math] ...

 

It is very confusing to think about them, actually the second one is very much "the super string theory", to think that I don't know where are you now,

you might be in the library, the class, or the food room .. so I might think that you are in [math]\{ (0.4, library), (0.35, class), (0.25, food room) \}[/math] ...

 

But when I go look for you (observe) I will find you at the library, so your position will become [math]\{ (1, library), (0, class), (0, food room) \}[/math],

Edited September 18, 2011 by khaled

[spacelike]

Yes, you see in the first interpretation, we have N parallel objects at first that increase exponentially with time .. in the second, we only have 1 object, which have N states

paired with their probabilities [math]P_i[/math], where [math]\sum_{i=1}^{N} P_i = 1.0[/math] ...

 

It is very confusing to think about them, actually the second one is very much "the super string theory", to think that I don't know where are you now,

you might be in the library, the class, or the food room .. so I might think that you are in [math]\{ (0.4, library), (0.35, class), (0.25, food room) \}[/math] ...

 

But when I go look for you (observe) I will find you at the library, so your position will become [math]\{ (1, library), (0, class), (0, food room) \}[/math],

 

I understand that much, but the point I'm trying to make is what would the story be like from my point of view?

Well you would say that I am always observing myself so I would find that I will be in the state [math]\{ (1, library), (0, class), (0, food room) \}[/math] for example, of course it could be any of the 3.

However, if we still base our interpretation on the Copenhagen interpretation then before you measure my position, the story is just as you said before:

[math]\{ (0.4, library), (0.35, class), (0.25, food room) \}[/math] according to you. So it depends on who's perspective we are considering.

 

But how is this possible? Because don't forget that those probabilities are to be interpreted (by the particular interpretation we are discussing) as a literal statement about what CAN happen. How can it be that from my point of view I have a probability of 1 of being in the library (for example) and a probability of 0 of being anywhere else, whereas from your perspective I have a finite probability of being somewhere else.

This means that according to me it is impossible for me to be anywhere but the library but according to you I can be at other places.

 

I understand all of this mathematically when you consider a single point of view individually, but you still haven't discussed what I'm getting at, and that is when you put the two together.

 

According to the Copenhagen interpretation even though I have a probability of 0 of being at the food room (according to me) it is still literally possible for you to actually observe that I AM at the food room!

This is a paradox.

 

A paradox to which the idea of many worlds has been proposed as a resolution.

Edited September 19, 2011 by spacelike

[khaled]

I understand that much, but the point I'm trying to make is what would the story be like from my point of view?

Well you would say that I am always observing myself so I would find that I will be in the state [math]\{ (1, library), (0, class), (0, food room) \}[/math] for example, of course it could be any of the 3.

However, if we still base our interpretation on the Copenhagen interpretation then before you measure my position, the story is just as you said before:

[math]\{ (0.4, library), (0.35, class), (0.25, food room) \}[/math] according to you. So it depends on who's perspective we are considering.

 

But how is this possible? Because don't forget that those probabilities are to be interpreted (by the particular interpretation we are discussing) as a literal statement about what CAN happen. How can it be that from my point of view I have a probability of 1 of being in the library (for example) and a probability of 0 of being anywhere else, whereas from your perspective I have a finite probability of being somewhere else.

This means that according to me it is impossible for me to be anywhere but the library but according to you I can be at other places.

 

I understand all of this mathematically when you consider a single point of view individually, but you still haven't discussed what I'm getting at, and that is when you put the two together.

 

According to the Copenhagen interpretation even though I have a probability of 0 of being at the food room (according to me) it is still literally possible for you to actually observe that I AM at the food room!

This is a paradox.

 

A paradox to which the idea of many worlds has been proposed as a resolution.

 

the probabilities in the superposition are based on a model of future expectation, such as Hidden Markov Models, ..etc

 

So, the probabilities in the superposition, doesn't lead much to reality .. but it can statistically lead the way, let's say for example

you use a Markov model, if you have never been to the library in years ago, then you still have (0, library) .. because it's based on

past outcomes, their distribution and their chain (order). Like saying "how many times he was in the library", "how many times he

was in the library on monday", "how many times he left the food room to the library" ...

Edited September 21, 2011 by khaled

[URAIN]

I believe that the universe is only what it is, and time-dimension is a fabrication to show progress

.. and that time travel is a one-direction operator applied to the degree of time-flow observation

 

time-flow is a continuous line, where one's observation is periodic over that line ...

 

Yes, no doubt universe is unic and it has no boundaries. It is infinite. For more you visit this forums, following thread

 

http://www.scienceforums.net/topic/59878-a-natural-phenomena-for-conservation-and-invariance/