the information paradox

[joshuam168]

my question is this. how can any scientist seriously consider this theory to be true? it contradicts the very fundamentals of physics, i.e. the laws of conservation of energy and matter. we know these laws to be true so how could sumone even try to contradict these, as did hawkings?

[iNow]

my question is this. how can any scientist seriously consider this theory to be true? it contradicts the very fundamentals of physics, i.e. the laws of conservation of energy and matter. we know these laws to be true so how could sumone even try to contradict these, as did hawkings?

 

This is still being researched, but (my own rough interpretation of) the current ideology seems to center around multiple universes. However, it's important for you to recall that Hawking himself announced his own change in position (that he does NOT believe a blackhole destroys information) at the GR17 conference in Ireland in July 2004.

 

http://news.bbc.co.uk/1/hi/sci/tech/3913145.stm

 

 

Click below for a transcript of his talk and some commentary around it:

 

http://math.ucr.edu/home/baez/week207.html

The Euclidean path integral over all topologically trivial metrics can be done by time slicing and so is unitary when analytically continued to the Lorentzian. On the other hand, the path integral over all topologically non-trivial metrics is asymptotically independent of the initial state. Thus the total path integral is unitary and information is not lost in the formation and evaporation of black holes. The way the information gets out seems to be that a true event horizon never forms, just an apparent horizon.

[fredrik]

my question is this. how can any scientist seriously consider this theory to be true? it contradicts the very fundamentals of physics, i.e. the laws of conservation of energy and matter. we know these laws to be true so how could sumone even try to contradict these, as did hawkings?

 

Regardless of how the attitude of this problem has evolved in Hawkings and other minds, I think it is a mistake to think along the lines that "we know certain laws to be true". In my opinion we really don't.

 

There is a subtle but important difference in optimally inferring something, and assuming this optimally inferred statement for the truth (whatever that really is btw). In a certain sense, the optimal inference is the closest thing we come to the truth, but still this makes our effective "truth" something dynamical and relative.

 

One could ask if any scientist would seriously claim to know the truth in the first place, because it sort of seems like an unscientific statement in itself.

 

/Fredrik

[BenTheMan]

joshuam---

 

There is no law of conservation of matter. I don't know what you're talking about. Consider this process---electron + positron to photons.

 

The information paradox is a problem because it kills unitarity, i.e. the idea that probabilities add up to one.

 

More technically, one can imagine making a pure quantum mechanical state, and throwing it in to a black hole. One can (easily) show that a pure quantum mechanical state can never be turned into a mixed quantum mechanical state by a unitary hermitian operator. But when the black hole decays via hawking radiation, all states are equally likely (i.e. thermal spectrum), so the state is maximally mixed. But quantum mechanics only consists of unitary (hermitian) operators, so the fact that the state is mixed is a paradox.

 

The calculations are correct, and are compeletely classical. They are completely consistent if one neglects quantum effects. This is a sign that something strange happens inside a black hole.

[pioneer]

Often what we call the truth, is just our best educated guess, which continues to evolve with time. An anology is a semi-solid data ball with a diffuse atmosphere above it. When it finally compacts, we get truth. But in the meantime, if we assume the fuzzy truth is a solid, because it is fluffier that it would in its final steady state, one can make connections that would not be possible it is was more compact.

 

Maybe a blackhole compresses information to a dense point. This will not be the fuzzy ball we are used to seeing. In that respect, the fuzzy part may not transfer, only the final compression. Or something like "The Euclidean path integral over all topologically trivial metrics can be done by time slicing and so is unitary when analytically continued to the Lorentzian. On the other hand, the path integral over all topologically non-trivial metrics is asymptotically independent of the initial state. Thus the total path integral is unitary and information is not lost in the formation and evaporation of black holes. The way the information gets out seems to be that a true event horizon never forms, just an apparent horizon." become a=b. The fuzzy gets compressed into close packing.

 

If we were to fluff the dense point a=b back, so we can interpret it in terms of the state of the art, it may not add up the same. As an analogy, two women may be talking and one says she likes the other's dress. This fuzzy truth goes into the black hole of the second women's mind where it is compressed into a nice feeling. But when she thinks about it and begins to decompresses the input, it now says "back stab". So she confronts the other woman on what she actually meant. The other women, goes literal on her and tells her the exact words or fuzzy data she imputted. Now the second women is a little confused since the decompression is still coming out different than the input. So she decides to give a complement about the other women's new shoes. This creates input into the first women, into her blackhole for compression. As she thinks about it decompression may now involve combining the complement with the original subtle, but by the book backstab. But the other women may have liked her shoes. But the original fuzzy data may decompress this with ambiguity.

 

If they had use solid truth straight up, it would not have led to an esculation of expanding theories that are based on nebulous truths. The current esculation of theory shows the truth is getting fuzzier. Solid truth should only line up in a very limited number of ways. Fuzzy truth allows for much more variation since the big balls can appear to touch more things, which would be restricted if the balls were smaller. Science needs a type of blackhole to help compressed the big balls and make them smaller. When this is decompressed, by a white hole, it will add up better.

[BenTheMan]

Often what we call the truth, is just our best educated guess, which continues to evolve with time. An anology is a semi-solid data ball with a diffuse atmosphere above it. When it finally compacts, we get truth. But in the meantime, if we assume the fuzzy truth is a solid, because it is fluffier that it would in its final steady state, one can make connections that would not be possible it is was more compact.

 

Pioneer this makes no sense. The information paradox is an artifact of a classical calculation not applying when quantum effects are considered. The Hawking calculation is completely classical (I know because I've done it). The space-time across an horizon is absolutely smooth, and a point-like observer won't even know he's crossing an horizon unless he tries to communicate with an outside observer.

 

However, because the black hole is growing, it means that the space-time aroud the black hole is changing. When one takes into account the quantum field theory on a curved space-time, one finds that when the metric changes (i.e. it is dynamic), particles are generically created. I know because I have done the calculation. If you don't believe me, look here:

http://en.wikipedia.org/wiki/Bogoliubov_transformation

 

The information pradox is exactly what I said, and it is painfully obvious to me that you don't know what you're talking about. There is no``compression of information''---information, in a quantum system, is a very abstract concept. You a.so cut and paste a quote from Hawking's speech at the GR17 conference without giving him credit, and I can explain to you what it means if you want. And there is no ``solid truth'' and ``fuzzy truth''.

 

Please don't try to pass tripe like this as an explanation.

[swansont]

As I had recently pointed out in another thread, if you have an explanation that is an alternative to accepted science (physics, in this case) then the appropriate area to post it is in speculations. People asking questions here want actual answers, not WAGs.

[BenTheMan]

WAG = ``Wild Ass Guess''?

[swansont]

WAG = ``Wild Ass Guess''?

 

Bingo.

[Severian]

The information paradox is not really much of a worry in my opinion because we do not have a consistent theory of gravity at the quantum scale. Once we have one, if the problem persists then it will be serious. But who knows what quantum weirdness we will have to come up with to explain gravity...

[Farsight]

As I had recently pointed out in another thread, if you have an explanation that is an alternative to accepted science (physics, in this case) then the appropriate area to post it is in speculations. People asking questions here want actual answers, not WAGs.

 

Can I remind you all that the "accepted science" here is speculation with no evidential proof, and no prospect of the same. What is considered to be the "actual" answers today might not, in the fullness of time, turn out to be correct.

[Reaper]

Can I remind you all that the "accepted science" here is speculation with no evidential proof, and no prospect of the same.

 

 

There is overwhelming evidence for their correctness. That is why it is called "accepted science".

[Farsight]

Wrong, Lockheed. There is no evidence regarding the black hole information paradox. You might claim that some mathematical proof is evidence, but it is not. It might one day be shown to be based upon a flawed axiom.

 

wiki Black hole information paradox

[BenTheMan]

Farsight---

 

It is a semi-classical calculation, and very general. Either you are claiming that the classical theory (GR) is wrong, or that quantum field theory is wrong. I stress this again for your benefit---I know because I've done the calculation. It seems that your only contributions to this thread are to make wrong comments and to link to wikipedia articles that don't support your points.

[Farsight]

No, I said what I said. Calculations do not provide evidence of hypothesis. And don't put words into my mouth.

[BenTheMan]

Aparently you're not familiar with how physics works. Unless someone can find a reason why something shouldn't happen (other than trying to EXPLAIN it with hand waving and optical illusions), then it is taken as evidence that it should happen. In this respect, there is as much evidence for information loss as there was for light bending in a gravitational field at the turn of the century. The only difference is that one experiment is easy to preform, and the other is not.

 

I didn't think I needed to tell you this.

[Farsight]

Aparently you're not familiar with how physics works. Unless someone can find a reason why something shouldn't happen.. then it is taken as evidence that it should happen. In this respect, there is as much evidence for information loss as there was for light bending in a gravitational field at the turn of the century. The only difference is that one experiment is easy to perform, and the other is not.

 

I can't believe I heard that. Whatever next, I can't disprove the existence of God, so you take that as evidence that God exists? Don't be so utterly ridiculous. Watch my lips: there is no evidence for the black hole information paradox. And it looks like there never ever will be. It's an issue of hypothesis. Now get a grip and read what I actually said:

 

Can I remind you all that the "accepted science" here is speculation with no evidential proof, and no prospect of the same. What is considered to be the "actual" answers today might not, in the fullness of time, turn out to be correct.

[swansont]

Can I remind you all that the "accepted science" here is speculation with no evidential proof, and no prospect of the same. What is considered to be the "actual" answers today might not, in the fullness of time, turn out to be correct.

 

I don't think that is a correct assessment of this situation. Quantum mechanics and relativity are accepted science, and pronouncements about "fuzzy truths" etc. are out of place here. Ben explained the main issue about the so-called paradox; that's accepted science. If you want to critique that (as Severian did by pointing out that we really need to reconcile QM and GR to get a full answer), go right ahead. But that's not the same as "anything goes, so I'll post nonsense"

[BenTheMan]

I can't disprove the existence of God, so you take that as evidence that God exists?

 

Aside from this being terribly outside the scope of this discussion, it is never a question that science can answer, because it is not an objective question---it is a subjective question. If you think that science disproves the idea of God, then you have too narrow a scope of what ``God'' means. Specifically, the concept of ``God'' has no meaning in science---it's like asking if the sun in female.

 

The correct statement would be that there is no evidence for God's existence, however, one could imagine a God that is consistent with all that we can test. Whether or not that God is somehting that people believe in (i.e. the same God of the Koran or the Bible) is the topic of another thread in another forum. Anything more than that and you're just stating your beliefs.

[Farsight]

Swansont: granted re "anything goes". I was injecting a caution because there's a significant number of conjectures underlying the subject of discussion, and a dearth of actual evidence.

 

BenTheMan: OK let's drop the God stuff. But take your line unless someone can find a reason why something shouldn't happen then it is taken as evidence.. and you end up with the Boltzman Brains article in New Scientist this week.

 

Can I add that I think the information paradox is an artefact rather than a genuine mystery. Can I also say that IMHO a black hole destroys information utterly.

[BenTheMan]

BenTheMan: OK let's drop the God stuff. But take your line unless someone can find a reason why something shouldn't happen then it is taken as evidence.. and you end up with the Boltzman Brains article in New Scientist this week.

 

So the Boltzmann Brain stuff is generally by a guy named Don Page, who is as intelligent as they come. He educated himself during high school (his parents were missionaries or some such in Alaska) and then went to Cambridge to get a PhD with Hawking. See this (serious) paper by him: http://arxiv.org/PS_cache/arxiv/pdf/0708/0708.0573v2.pdf. Page is a very nice man (and a Christian, coincidentally), but he certainly pushes science as far as it possibly can go.

 

Anyway, my line is the line taken by ALL scientists, I promise. See Sverian's comment, for example: he says something like ``It's not a problem because we don't know how to quantize gravity''. This is correct---no one expects there to be any information paradox once we figure out how to quantize gravity. Then there should be a symmetry which forbids it, or some more general explanation as to why it LOOKS like information is lost in the semi-classical calculation. This is how we know that something else has to pop up---the physics isn't consistent.

 

But saying that something shouldn't happen because it doesn't make sense is introducing a bias into the science. This is just as bad as saying ``God did it'', whether you are willing to admit it or not. There are many things in science which doesn't make sense, and the best discoveries are the unexpected ones.

 

Can I add that I think the information paradox is an artefact rather than a genuine mystery. Can I also say that IMHO a black hole destroys information utterly.

 

A professor here who works on the problem, Samir Mathur, has elevated the Information Loss ``Problem'' to a theorem, as I recall when I saw him lecture on it. It is absolutely an artifact of not having the correct theory of gravity, you are certainly correct about this. (If you want, I can explain Hawkings current position on the problem.)

 

As for black holes destroying information utterly, this is in no way consistent with quantum mechanics. One can show (as I said earlier) that unitary operators forbid information from being lost. This means that, if you want a good interpretation of probabilities, the evolution of the system has to be governed by unitary operators. If information is lost, the evolution is unabiguously non-unitary---a stronger statement is that a pure state can never evolve into a mixed state when that evolution is goverened by unitary operators. Again, the calculation is like three lines long, and I can show it to you if you want. It's a problem in Sakurai's QM textbook, I think in Chapter 3.

[joshuam168]

joshuam---

 

There is no law of conservation of matter. I don't know what you're talking about. Consider this process---electron + positron to photons.

 

 

sorry about that.....i meant law of conservation of mass.

[swansont]

joshuam---

 

There is no law of conservation of matter. I don't know what you're talking about. Consider this process---electron + positron to photons.

 

 

sorry about that.....i meant law of conservation of mass.

 

(fixed quote tag)

 

No law of conservation of mass' date=' either. E=mc[sup']2[/sup] and all that. Energy is the conserved quantity.

[joshuam168]

(fixed quote tag)

 

No law of conservation of mass, either. E=mc² and all that. Energy is the conserved quantity.

 

dude law of conservation of mass is simple chemistry. i could go and quote it to you out of my chemistry book if you would like.

[BenTheMan]

Please do so.

 

Don't you know that some chemical reactions produce heat?