Black hole information paradox and determinism

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Hello, layman here, I have a simple question, could you please clear this up for me?

Whenever I read about the information paradox, it always appears to me that it is automatically assumed that quantum fluctuations / virtual particle pairs are predictably random. Which leads to the loss of information at event horizons.

To me, this genuine randomness seems to be an unnatural assumption, to me the more natural would be that fluctations are deterministic, the whole universe is deterministic. But they appear predictably random to us because it's way beyond our ability to predict them, we would probably need to know the state of the entire universe for such a prediction (and see into the underlying field(s) that such fluctuations are the expressions of).

So, if we assume that quantum fluctuations are not random, they just appear to be, is there still an information paradox?
(It would appear to me that in this case, the information would simply leak out into the rest of the universe, while the black hole is evaporating. We just can't track that information.)

Thank you!
 

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  • #2
phinds
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... to me the more natural would be that fluctations are deterministic, the whole universe is deterministic.
The Heisenberg Uncertainty Principle is not a measurement issue, it is a description of nature and it says categorically that the universe is not deterministic.
 
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The Heisenberg Uncertainty Principle is not a measurement issue, it is a description of nature and it says categorically that the universe is not deterministic.
Yes, as far as we can tell, it appears not deterministic. But that doesn't necessarily mean that it really is, hence my question.
 
  • #4
phinds
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Yes, as far as we can tell, it appears not deterministic. But that doesn't necessarily mean that it really is, hence my question.
So you do not believe in the validity of the HUP ?
 
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So you do not believe in the validity of the HUP ?
Well yes, I tend to think that a belief in genuine randomness always contains an element of magical thinking (so Einstein was right with the dice thing). I may be wrong though of course.

It's just that in every experiment ever conducted, we see the HUP verified, because our experiments are a lot smaller in scale than the universe. The difference is so big that there is no way for us to detect the order behind the apparent randomness. So for all practical purposes, quantum randomness is valid.
 
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berkeman
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Thread closed for Moderation...
 
  • #7
berkeman
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Thread re-opened after straightening out duplicate account problem.
 
  • #8
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we would probably need to know the state of the entire universe for such a prediction (and see into the underlying field(s) that such fluctuations are the expressions of).
As long as we're using the theory of quantum mechanics, even knowing the state of the entire universe won't help. The randomness is a fundamental element of the mathematical formulation of the theory (google for "Born Rule") and applies no less to the state of the entire universe than to the state of any smaller part. (You should also be aware that the randomness goes much deeper than just "quantum fluctuations", a dubious idea generally misrepresented in the popular press).

There is of course the possibility that there is some deeper theory that underlies quantum mechanics, and that the apparent randomness of quantum mechanics is just the result of our not understanding the machinery of that hypothetical underlying theory. However, despite the best part of a century trying, no one has been able to come up with plausible candidate theory, and there are theoretical and experimental results (google for "Bell's Theorem") that say that any such theory will be at least as strange and "unnatural" (your word) as quantum mechanics itself.

But with all of that said.... Yes, it is possible that if such a theory exists, it might resolve the black hole information paradox. But without a candidate theory this is mere idle speculation.
 
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As long as we're using the theory of quantum mechanics, even knowing the state of the entire universe won't help. The randomness is a fundamental element of the mathematical formulation of the theory (google for "Born Rule") and applies no less to the state of the entire universe than to the state of any smaller part. (You should also be aware that the randomness goes much deeper than just "quantum fluctuations", a dubious idea generally misrepresented in the popular press).

There is of course the possibility that there is some deeper theory that underlies quantum mechanics, and that the apparent randomness of quantum mechanics is just the result of our not understanding the machinery of that hypothetical underlying theory. However, despite the best part of a century trying, no one has been able to come up with plausible candidate theory, and there are theoretical and experimental results (google for "Bell's Theorem") that say that any such theory will be at least as strange and "unnatural" (your word) as quantum mechanics itself.

But with all of that said.... Yes, it is possible that if such a theory exists, it might resolve the black hole information paradox. But without a candidate theory this is mere idle speculation.
What I mean is, how can you be certain that the Born rule applies no less to the state of the entire universe than to the state of any smaller part? Isn't this just an unproven assumption based on our experiments, where it does seem to apply?

So I think I wasn't implying an actual underlying theory, more like an extension to QM. What seems random "locally" might not be random "universally".
 
  • #10
phinds
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So I think I wasn't implying an actual underlying theory, more like an extension to QM. What seems random "locally" might not be random "universally".
I don't follow your logic on that. If things are random locally then the universe is not deterministic. How does "universally" enter into it and what does that even mean in this context?
 
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I don't follow your logic on that. If things are random locally then the universe is not deterministic. How does "universally" enter into it and what does that even mean in this context?
No, I meant that things appear random locally, but actually they aren't. But we would have to look at the entire universe all at once (or nearly the entire universe all at once) to be able to see the determinism behind all the apparent randomness. But we will probably never be able to do anything like that. So this assumption can't be proven either.
 
  • #12
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how can you be certain that the Born rule applies no less to the state of the entire universe than to the state of any smaller part? Isn't this just an unproven assumption based on our experiments, where it does seem to apply?
Of course it is an unproven assumption. That's what "postulate" means, and this is one of the postulates of QM.
So I think I wasn't implying an actual underlying theory, more like an extension to QM. What seems random "locally" might not be random "universally".
That wouldn't be quantum mechanics, it would be a new theory that isn't QM but reduces to QM when applied within the domain of validity of QM in rather the same way that general relativity reduces to Newtonian gravity when the gravitational field is weak. Such a thing is certainly possible, but without a serious proposal it's still just untestable speculation.
 
  • #13
phinds
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No, I meant that things appear random locally, but actually they aren't. But we would have to look at the entire universe all at once (or nearly the entire universe all at once) to be able to see the determinism behind all the apparent randomness. But we will probably never be able to do anything like that. So this assumption can't be proven either.
OK, so what I was missing is that you are assuming that the HUP is not true.
 

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