5 ms·

As it stands, as far as we know, Hawking radiation is completely thermal and random, so as the article states, you can't tell the initial state from the final s

by platz 7y ago

As it stands, as far as we know, Hawking radiation is completely thermal and random, so as the article states, you can't tell the initial state from the final state even if you collect all the radiation. > observing the accretion disk Well that is not part of the black hole now, is it.

posterboy 7y ago
Kindly riddle me this. If a black hole was a closed system, then the premisses, that information inside will become lost, would be trivially true by the (2nd?) law of thermodynamics. There's energy going in, so it isn't hermetically sealed. Thus, the accretion disk is part of the system. But if there's no correlated information coming out, it's closed one-way. You say there is radiation coming out, theoreticly, and I know that radiation is information. It's information in one strict sense, but not in the other--what are the different scopes; Is the radiation not observable? Are the laws of thermodynamics seemingly violated, that is, is the theory not complete (rhethoric question); Thus your remark was in effect non-constructive, as you cannot prove one unknown with another, can you? Nevermind the kind of scary question whether any system in the grand scheme of things is closed at all. BTW another comment mentioned conservation of momentum and charge. I wonder, in the focal point of an ideal lense, in theory, can the image be reconstructed? Well, by looking at the flame quite trivially, at least, albeit not in the perspective of the focal point (not easily without ambiguity, surely). Is this what Tao's one-pixel-cam is about?
ailideex 7y ago
> As it stands, as far as we know, Hawking radiation is completely thermal and random Is it? Can you cite? IANAP but the best I could find on the matter is: https://en.wikipedia.org/wiki/Black_hole_information_paradox https://en.wikipedia.org/wiki/Black_hole_information_paradox > There are various ideas about how the paradox is solved. Since the 1997 proposal of the AdS/CFT correspondence, the predominant belief among physicists is that information is preserved and that Hawking radiation is not precisely thermal but receives quantum corrections. Maybe that is wrong, but not sure what the basis for the claim to the contrary is. Another citation which speaks to the views of Hawking on the matter: https://iopscience.iop.org/article/10.1088/1367-2630/7/1/203#nj185922bib67a https://iopscience.iop.org/article/10.1088/1367-2630/7/1/203... > Now if information is really lost down a black hole as Hawking originally proposed [64], and if the Hawking radiation really has negligible correlations between what is emitted early and late, then it might be true that A/4 −tr(ρ ln ρ), suitably regularized, would never decrease. But since this information-loss proposal has been controversial since near the beginning [65, 66], and since now even Hawking has given it up [67]; Direct quote from Hawking: https://www.newscientist.com/article/dn6193-hawking-concedes-black-hole-bet/#ixzz5xjLC8rNa https://www.newscientist.com/article/dn6193-hawking-concedes... > “If you jump into a black hole, your mass energy will be returned to our Universe, but in a mangled form, which contains information about what you were like, but in an unrecognisable state.”
- platz 7y ago
  The reason the black hole information paradox is a paradox is because it presents us with an unresolved contradiction ("There are various ideas about how the paradox is solved"). So there are several theories with try to resolve the contradiction, but they are all competing theories (i.e. physicists do not agree). Also, some of those theories assume Anti-de Sitter space which contradicts the positively mesaures cosmological constant. So in the sense that before the paradox is resolved, we don't know if the radiation is thermal or not, but the idea of the radiation being thermal was based on the existing bog-standard theory of QM and GR. What is under debate is how that needs to be modified, which we haven't agreed yet.

by platz 7y ago

posterboy 7y ago

Kindly riddle me this. If a black hole was a closed system, then the premisses, that information inside will become lost, would be trivially true by the (2nd?) law of thermodynamics. There's energy going in, so it isn't hermetically sealed. Thus, the accretion disk is part of the system. But if there's no correlated information coming out, it's closed one-way. You say there is radiation coming out, theoreticly, and I know that radiation is information. It's information in one strict sense, but not in the other--what are the different scopes; Is the radiation not observable? Are the laws of thermodynamics seemingly violated, that is, is the theory not complete (rhethoric question); Thus your remark was in effect non-constructive, as you cannot prove one unknown with another, can you? Nevermind the kind of scary question whether any system in the grand scheme of things is closed at all. BTW another comment mentioned conservation of momentum and charge. I wonder, in the focal point of an ideal lense, in theory, can the image be reconstructed? Well, by looking at the flame quite trivially, at least, albeit not in the perspective of the focal point (not easily without ambiguity, surely). Is this what Tao's one-pixel-cam is about?

ailideex 7y ago

> As it stands, as far as we know, Hawking radiation is completely thermal and random Is it? Can you cite? IANAP but the best I could find on the matter is: https://en.wikipedia.org/wiki/Black_hole_information_paradox https://en.wikipedia.org/wiki/Black_hole_information_paradox > There are various ideas about how the paradox is solved. Since the 1997 proposal of the AdS/CFT correspondence, the predominant belief among physicists is that information is preserved and that Hawking radiation is not precisely thermal but receives quantum corrections. Maybe that is wrong, but not sure what the basis for the claim to the contrary is. Another citation which speaks to the views of Hawking on the matter: https://iopscience.iop.org/article/10.1088/1367-2630/7/1/203#nj185922bib67a https://iopscience.iop.org/article/10.1088/1367-2630/7/1/203... > Now if information is really lost down a black hole as Hawking originally proposed [64], and if the Hawking radiation really has negligible correlations between what is emitted early and late, then it might be true that A/4 −tr(ρ ln ρ), suitably regularized, would never decrease. But since this information-loss proposal has been controversial since near the beginning [65, 66], and since now even Hawking has given it up [67]; Direct quote from Hawking: https://www.newscientist.com/article/dn6193-hawking-concedes-black-hole-bet/#ixzz5xjLC8rNa https://www.newscientist.com/article/dn6193-hawking-concedes... > “If you jump into a black hole, your mass energy will be returned to our Universe, but in a mangled form, which contains information about what you were like, but in an unrecognisable state.”

platz 7y ago
The reason the black hole information paradox is a paradox is because it presents us with an unresolved contradiction ("There are various ideas about how the paradox is solved"). So there are several theories with try to resolve the contradiction, but they are all competing theories (i.e. physicists do not agree). Also, some of those theories assume Anti-de Sitter space which contradicts the positively mesaures cosmological constant. So in the sense that before the paradox is resolved, we don't know if the radiation is thermal or not, but the idea of the radiation being thermal was based on the existing bog-standard theory of QM and GR. What is under debate is how that needs to be modified, which we haven't agreed yet.