[Guest]

what will you find behind the door that is one door away from heaven?

[Izzy]

I think the point was that he consciously wanted a tiger to surprise him, which isn't possible, but should be by your definition of the door.

[Guest]

if you really want to go into quantum physics, then we can, but i don't really want to... to long of a subject... and just going a little into it, then if you wanted absolutely nothing to be changed, then you will get to "visit" another dimension where you have died previously, and you can't stay forever, because you will "fade" so to say... meaning you can exist in many dimensions and not know it, but when you do go to another dimension, you can't stay long because you aren't meant to be there.... what i mean by exist, is that there are many, many versions of you out there, side by side, and every time you make a decision on what to do, another world is made for the other decisions that you didn't make...

EDIT: i love quantum physics.... it confuses people!

Edited January 27, 2010 by chrispen

[Izzy]

The multi-verse theory used to be my favorite explanation for the dual slit trick seeing as it's pretty much the only one that actually makes sense. ..Until this one guy made it look like total bull. Need to get offline for a bit (>_>), but I'll look into the criticisms of it later and see if I can find the post. Blew my mind, but was over a year ago and I'm having trouble remembering the exact details.

[Guest]

oh... i thought that i got it right. just read a book about quantum physics, and i thought it was pretty interesting...

[unreality]

the Law of One or Many suggests there is one or infinite universes, and that determines whether we are here by luck/divinity (One) or by the anthropic principle (Many)

[Guest]

yep i got that part down...

[Izzy]

Meh, couldn't find the post I was looking for, but was thinking about this on the bus this morning. What I'm about to say doesn't disprove it in any sense, but makes the entire theory sound devilishly improbably.

In the multi-verse, a new universe doesn't spring into creation with every human movement, it's with the movement of EVERY atom, every proton, neutron, and electron, every quark, every photon, each particle that possibly make up those mentioned that we don't yet know about. Now, any one of those have an almost infinite possible directions in which they can travel and at which speeds. So, just for one photon, in an amount of time so minuscule that as humans we can't even comprehend it, zillions of new universes form for the "choices" made by this individual photon. Multiply that by every particle in this universe, and those universes are created. Then realize this is going on in EVERY universe at the same time. From this, we can see more universes are in existence than any number we can comprehend. A number so large it would take a computer decades to write the scientific notation of it.

It's like, you really think we wouldn't have noticed one of those by now? That something wouldn't go wrong in *one* of them, giving us the ability to observe them?

[Guest]

that St Peter fella waiting there to turn around the rest of us "heathen atheist swine?"

[Guest]

1000th post! Woo!

Meh, couldn't find the post I was looking for, but was thinking about this on the bus this morning. What I'm about to say doesn't disprove it in any sense, but makes the entire theory sound devilishly improbably.

In the multi-verse, a new universe doesn't spring into creation with every human movement, it's with the movement of EVERY atom, every proton, neutron, and electron, every quark, every photon, each particle that possibly make up those mentioned that we don't yet know about. Now, any one of those have an almost infinite possible directions in which they can travel and at which speeds. So, just for one photon, in an amount of time so minuscule that as humans we can't even comprehend it, zillions of new universes form for the "choices" made by this individual photon. Multiply that by every particle in this universe, and those universes are created. Then realize this is going on in EVERY universe at the same time. From this, we can see more universes are in existence than any number we can comprehend. A number so large it would take a computer decades to write the scientific notation of it.

It's like, you really think we wouldn't have noticed one of those by now? That something wouldn't go wrong in *one* of them, giving us the ability to observe them?

Your approach is a little unmathematical (that's just an observation, not a criticism! )

Suppose the structure of our universe is such that multiple realities don't interact with each other. This would seem to be the case, after all, and if it were so, it is simply impossible that one would "go wrong" and interact with others. It's not in their nature, or their structure, to do so. If the probability of something like that happening is precisely zero, it really doesn't matter how many realities there are, it still wouldn't happen. The objection seems to be based on the fact that the theory has mind-boggling implications, which in itself is a pretty poor objection.

that St Peter fella waiting there to turn around the rest of us "heathen atheist swine?"

Yes imagine their surprise when it turns out to be Baron Samedi. Bwahahaha!

[Izzy]

Suppose the structure of our universe is such that multiple realities don't interact with each other.

Then it doesn't answer the dual-slit trick, the reason it was created in the first place.

[Guest]

Then it doesn't answer the dual-slit trick, the reason it was created in the first place.

The dual-slit behaviour results from a superposition of states which shows wave interference until the point where the light hits its target, interacting with its environment, at which point each photon appears to "decide" exactly where it really is, the probability of any given position being determined by the waveform (if there are many photons, you see the interference pattern as a visible indication of that probability distribution). It's that "decision" made by the photon, the apparent wave-form collapse into a single outcome, that poses the problem.

The many-worlds view is that no such decision is really made. The causal interaction of the light with its environment results in the environmental effects diverging in ways which no longer interact with the effects of other outcomes.* So the observer who measures one photon ending up in one position has no means of interacting with the environment in which that same photon was observed to end up somewhere else, but neither outcome is more or less real than the other.

Otherwise we are left with the problem of determining how the act of interaction with the environment caused a probabilistic superposition to be resolved into a single state. This requires either that the universe works probabilistically, by "God throwing dice", or that there is some other extra mechanism involved. One of the main strengths of the many-worlds interpretation is that no such additions are required. Even though the multiplicity of worlds seems complex, the rules of the system are simpler, so it has Occam's razor on its side.

* Strictly speaking that might be slightly incorrect. I think maybe the point you were making is that there is an inconsistency between a closed system (say, a single photon) being able to interact with itself as a superposition of many states, and the larger environment being unable to do so, since this may also be considered a closed system, albeit a much bigger one. As I understand it, the difference is mainly one of probabilities. In order to get such interaction you need a very tidy system, and that's easier to arrange on a smaller scale. However, what you seemed to be suggesting earlier is that the sheer quantity of parallel realities would cause the system to break. The separation of "worlds" may be probabilistic rather than absolute, but it still works in a way which tends to be absolute on a large scale, and the vast quantity of worlds isn't going to change that. There's no need to suppose that reality requires some physical storage medium, with the limitations that would entail, so the many worlds would not run out of space and start bumping into each other. Considering it as a mathematical system, it needn't be bound by any restrictions which you would associate with finite space or dimensionality, it's determined only by the rules that define it.

[Izzy]

Man I seriously need to uncover that post. Or become a physicist, meh. Chances are, I'm entirely wrong. I'm just going to point out now that my arguments are baseless, formed from reasoning that to me just makes sense to me. If I'm wrong, I'm sorry. I don't claim to know the answers, so.. consider this a form of devil's advocacy? Anyway.

I'm sort of iffy on your post. This is how I'm understanding it: The interference pattern arises from a probabilistic shape (that looks like this), where each individual photon shot has a certain chance of landing on any one of those spots. The more photons shot, the clearer the pattern is.

Okay, good so far.

Then you lose me. The way I've always understood the multiple worlds is like this:

When a quantum system is faced with a choice of alternatives such as a particle going through one of two or more slits, then rather than the wave function entering a superposition, everything sort of splits into a number of realities that are equal to the number of options available, all identical apart to the option chosen by the particle. But then the universes overlap (only where the interference is taking place), until decoherence (giving the appearance of wave function collapse) sets in, separating them into non-interacting independent realities. We also split, only ever seeing one reality.

But there are some unanswered questions with this. Why does the interference pattern collapse when we're observing which slit the photon goes through? It should just tell us both, continue splitting, and create the pattern instead of no pattern. Or tell us which slit it went through in our universe, but still continue the interference pattern. There's no reason observing should mess it up, according to this theory. If the atom is able to sense the presence of itself in these multiple realities (supposedly the reason it keeps choosing elsewhere), why can't we? The whole zillions of zillions of universes being produced per zillionth of a second doesn't make sense to me. Umm. Man, long post, not that much going for me. Meh.

So I'm thinking it's something else. I know I'm not really disproving it, and am not really suggesting anything else, but it just.. doesn't seem right.

[Izzy]

Also, think of how fecking complex that would be. I don't think you get to claim Occam's Razor.

[Izzy]

So I grabbed my iTouch and a Monster, decided to go for a walk to mull things over. I came up with God, monsters, energy fluctuations, and entropy. (Haha, can you see the logic in that? God makes me think of monsters, making me think of Monster Energy Drink, making me think of craziness, which = entropy. Anyway, it all makes sense, I swear.)

I'm not actually trying to start a(nother) religious debate here. My post (specifically this part) is aimed at Octopuppy, because I know we share similar beliefs, and maybe the analogy will make sense.

Basically, the multi-worlds interpretation is the god of quantum mechanics. An answer was needed to explain some extraordinary phenomenon, so solutions were hypothesized, the multi-worlds being among them. Similar to the gods of the early years, current technology didn't provide a meaningful solution, it's all theoretical. This answer made sense, it fit, but ultimately posed more questions than it answers (which isn't necessarily bad). Regardless of experiments, the MW have never been detected, never been formed into a math equation that would ultimately prove them being real, and so forth, the main point being that it's all highly theoretical. Still more likely than God, but.. hardly. I hope you can see why I have to remain skeptical. Just because it nicely answers something it was designed to do, doesn't mean there's any validity to it.

A hypothesis that can be just as likely is the idea of a forth-dimensional monster being expressed in our dimension through the accumulation of photons and other microscopic particles. One of the properties of this monster is how it draws photons to itself, and they just happen to stick to it in the way of the interference pattern. Yeah, I know, bull, but no less likely regarding complexity and encountering it with regards to the MW.

Now, energy fluctuations. According to our current model, the energy in the universe, able to be neither created nor destroyed, cancels out exactly to zero. Doing any work (such as splitting a universe) requires energy, just the same as this new universe would require energy. Wouldn't we notice either a loss of energy in our own universe or at least some weird fluctuation that is noticeable and measurable, meaning something we can't see has happened? Also, what's the force driving the universes apart? I'm thinking something universal like gravity or electromagnetism, but like these two and the strong and weak forces, other particles would have to be found explaining it, and so far, as far as I know, none have even been theorized.

Finally, entropy. The universe(s) get more orderly as time goes on, but a huge sense of untidiness had to exist way back when. So "mess ups" would have to be fairly common (eh, maybe not), getting less common as time goes on. So, I dunno, this point sucks, it made sense when I was walking. But the universe isn't really, even now "tidy" in any sense, so I don't see where the necessary tidiness comes in. Meh.

Anyway. Yeah. Homework time.

[Guest]

I should point out I can't really claim to know what I'm on about with quantum mechanics but I won't let that stop me. Like Feynman said, "if you think you understand quantum mechanics, you don't understand quantum mechanics". I know perfectly well I don't understand it, so that makes me well qualified.

When a quantum system is faced with a choice of alternatives such as a particle going through one of two or more slits, then rather than the wave function entering a superposition, everything sort of splits into a number of realities that are equal to the number of options available, all identical apart to the option chosen by the particle. But then the universes overlap (only where the interference is taking place), until decoherence (giving the appearance of wave function collapse) sets in, separating them into non-interacting independent realities. We also split, only ever seeing one reality.

I'm not sure that the number of realities going on at any point in time is all that important, so you could view it the way you just described. I was describing it as being more like one reality in which the particle acts like a wave, which then splits at the point of decoherence. You could view that as a partial split, because only things which have potentially been affected by the particle are different, the rest of the universe is carrying on as normal. Things get pretty mind boggling when you start thinking along those lines, but I'll take that as a good sign.

But there are some unanswered questions with this. Why does the interference pattern collapse when we're observing which slit the photon goes through?

I'm not sure how best to answer that (getting a bit out of my depth, glug, glug). To me the odd bit is not why there is no interference pattern here, but why probability waves show interference patterns at all. Still, they do, and that being the nature of things, it seems to allow two possible outcomes to cancel each other out and become impossible where the waves cancel out, but only when the effects are otherwise indistinguishable, and observing which slit the photon goes through doesn't meet those criteria. That's all pretty wierd but not really in dispute. I don't know if the many-worlds interpretation explains why that happens, I don't think it's an answer to all questions in quantum physics, just a way of looking at decoherence.

I'm inclined to think that the big picture would have the photon remaining a probability wave at all times, and our "particle" interpretation of it being simply a case of us only getting to see a little bit of the wave. So where interference prevents a photon from being observed, it's not so much that there is no reality in which the photon goes there, rather the probability wave evaluates to zero there, but in some sense it's still part of our model so if we change the rules by observing which slit it came from we can make the probability non-zero in that place. That's perhaps another way to look at the many-worlds model. You could see it as one world in which all possible outcomes happen (naturally, because everything consists of waves, not particles), but we humans only perceive a small part of things, since most of the probability space isn't connected to us.

If the atom is able to sense the presence of itself in these multiple realities (supposedly the reason it keeps choosing elsewhere), why can't we?

Because of the very limited circumstances in which that happens (see above). Much harder to engineer on a larger and messier scale.

Also, think of how fecking complex that would be. I don't think you get to claim Occam's Razor.

It depends on what you mean by complex. After all, a Mandelbrot Set looks pretty complex, but the rules for creating it are pretty simple. Likewise, the many-worlds idea is a simple model to explain what we experience. The fact that it implies a notion of reality which is vastly greater than what we experience is incidental. As long as it implies what we do experience, that's all that matters.

Just because it nicely answers something it was designed to do, doesn't mean there's any validity to it.

It's only a model. Its worth depends on its simplicity and its correspondence with observation. "Many worlds" or a larger "probability space" such as I described may not produce observable effects any different from if there was only one course of events, determined probabilistically. However, the former models are arguably more simple, elegant and complete, even though they may be difficult to visualise. You could consider it a way of looking at things rather than an assertion, especially if it can be neither confirmed or refuted by evidence. But if it's the simplest and most elegant model we have, it has some value.

Now, energy fluctuations...Doing any work (such as splitting a universe) requires energy, just the same as this new universe would require energy.

Splitting the universe is not "work" in the sense of requiring energy, since it's part of a higher-level structure of what makes the universe what it is. Likewise no force is required, just like we don't need any force to keep time moving along. As an analogy, consider a book in which the author has written two endings, two versions of the last chapter. How much effort must the characters in the book make in order for the story to split in two? None, they are not aware of it. As far as the characters in either version of the chapter is concerned, theirs is the only version of events and no split has occurred at all.

[Izzy]

Man, I hate not knowing, but I just don't know. You raise good points. Once again, my view of the universe(s) has been shattered, thanks. ;P

Shower time, shall think about this all in depth, and see if I come up with anything.

(The cleaning in showering, the exercising in walking/jogging/skating, and the sleeping in sleeping have all become meaningless to me, somehow replaced with thinking-time. Gotta say I love it.) Blehs. Stupid QM turning my brain to mush.

[Guest]

... you guys are starting to scare me... jk jk! but i wasn't expecting this when i made this topic...

[Izzy]

Scaring in a good way, right?

Worth mentioning. I bought this book yesterday, along with Sex, Drugs, and Cocoa Puffs (which is hilarious). Hopefully it'll better my understanding of the subject without scaring me away with the math..

[Guest]

hahaha.... no not in a good way, but not in a bad either... it's like i took Valium, and now i don't feel anything. jk jk, it's a good way, and i'm glad you guys are thinking about this pretty hard.

[Guest]

I want my door to be transparent so I can see if I really want to walk through it or not.

[Guest]

this book

Oooh. I think I'll buy that myself. That way I might be able to discuss this with some idea of what I'm talking about, since a lot of what I "know" about quantum physics comes from the superficial woo you get in popular science books (which, as a genre, I have come to despise, since they promote a little knowledge and no understanding). This looks like the sort of book you can really get thinking about. Mmm.

[Izzy]

^Just opening it up and looking at all the pretty equations will make you mathgasm (legit).

[Guest]

ha ha ha... and Semper R.. you always gotta make things simple... i like you answer, and i want to know if you would like plastic or glass???