What is Information paradox: Definition and 41 Discussions

The black hole information paradox is a puzzle resulting from the combination of quantum mechanics and general relativity. Calculations suggest that physical information could permanently disappear in a black hole, allowing many physical states to devolve into the same state. This is controversial because it violates a core precept of modern physics—that, in principle, the value of a wave function of a physical system at one point in time should determine its value at any other time. A fundamental postulate of the Copenhagen interpretation of quantum mechanics is that complete information about a system is encoded in its wave function up to when the wave function collapses. The evolution of the wave function is determined by a unitary operator, and unitarity implies that information is conserved in the quantum sense.
As of November 2019, the paradox may have been resolved, at least for simplified models of gravity. (also see § Recent developments)

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  1. W

    I If nothing can escape a black hole, it follows that Hawking radiation can't exist?

    Or is Hawking radiation something? Can't be both, however if you choose one theory over another, why do you do so. Those of you who are younger will not remember a World without the information paradox, but when I was younger it did not exist in any way because nothing escaped the event...
  2. KDP

    I Brian Cox and the end of the Universe?

    Professor Brian Cox was on the TV last night. He stated that eventually everything will end up in black holes. When there is nothing left to absorb they will start evaporating via Hawking radiation until eventually they all disappear in a small flash of light and then there will be eternal...
  3. H

    A Is there a lost information paradox for quantum physics?

    Hi Pfs, When Stephen Hawking proposed the idea of black hole information it appeared that information could be lost. it was a problem in GR which is a dererminitic theory. Knowing initial data and Hamiltonian tells you what was and will be. It is not the case in quantum physics. things evolve...
  4. Grinkle

    B Why is the BH Information Paradox Called a Paradox?

    We don't have a quantum theory of gravity. To my B level thinking, losing information at the EH of a black hole is just one of multiple known places where QM meets relativity and it becomes clear that our understanding is incomplete. I don't see it as any different than making the same...
  5. S

    I Information lost at the Big Crunch?

    Let's imagine for a moment that the universe stopped expanding somehow (even though the evidence we have suggests this is not going to happen) and gravity made it contract until reaching a Big Crunch state. According to our actual understanding of physics and our current working models, Is it...
  6. Oldman too

    I A new approach to the information Paradox

    Summary: New black hole simulations that incorporate quantum gravity indicate that when a black hole dies, it produces a gravitational shock wave that radiates information, a finding that could solve the information paradox. Hello, Please excuse the rather "conversational" approach I'm using...
  7. nomadreid

    I Entangled particles in black hole decay?

    First, I was not sure whether this should go into the Relativity or the Quantum Physics rubric, but since the central question is about entanglement, I opted for the Quantum. I do not have the necessary sophistication to follow string theory arguments, and even most explanations in...
  8. J

    A What does the equation C = 12 J mean for black holes?

    Just saw a documentary about resolving Hawking's "information paradox". In my own lay terms the physicists appear to theorize resolving the paradox with with their proposed C = 12 J . C is the central charge (which I don't fully understand) and J is the total angular momentum of the black...
  9. S

    B Is the "Information Paradox" close to getting resolved?

    Is the "Information Paradox", close to getting resolved?
  10. S

    I Information Paradox in Black Holes and BSM

    If they could solve the information loss paradox in black hole https://en.wikipedia.org/wiki/Black_hole_information_paradox What other related problems it could solve in Beyond Standard Models or unsolved quantum questions, etc.? If the LHC could no longer detect new particles, could beyond...
  11. avischiffman

    B How to shorten this speech about BH?

    Hi guys I am writing a speech for a school video and I have a maximum of 3 minutes, but I've written 4 minutes and 17 seconds worth of stuff. I need help cutting the fat away giving me around 2 minutes and 45 seconds worth of stuff so that I can have some quick experiments and speak slower so...
  12. K

    A A question about the information loss paradox

    In the information loss paradox, people say that in quantum mechanics , time evolution is unitary. They usually do not say anything about the measurement process of if they do, they briefly say that the measurement process does not violate unitarity either if one takes into account the...
  13. A

    B Black hole information paradox and determinism

    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...
  14. B

    B Information paradox in black holes

    I have always been fascinated with black holes and information paradox. If quantum bits made up spacetime. Could the information getting inside a black hole be possibility encoded in its quantum bits? Look at https://www.quantamagazine.org/20150428-how-quantum-pairs-stitch-space-time/
  15. stevendaryl

    A Information Paradox for Unruh Radiation?

    I'm sure that there are limits to the analogy between the event horizon of black holes and the "Rindler horizon" for an accelerated observer, but there are a number of similarities: For Schwarzschild spacetime as described in Schwarzschild coordinates: Spacetime is static, and a rocket must...
  16. Will K

    B Unitarity and Entanglement: Examining the Fate of Information in Black Holes

    What happens to the information about the objects falling into the black hole? Are their states somehow contained in the Hawking Radiation, and if so, how? Or is the information scrambled as it passes the EH?
  17. A

    I LIGO BH Merger & Black Hole Information Paradox

    Has anyone analysed the LIGO merger detection http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 in the context of the BH information paradox? Is there any evidence that the gravitational waves carried any information that could compensate for the change in areas of the initial...
  18. W

    I LQC and the Information Paradox

    From my limited reading I get the impression that the bouncing black holes proposed by Rovelli and Vidotto implies a solution to the information paradox. The information comes back out when the bounce happens. But how does this relate to the idea of complimentarity? It seems the latter was the...
  19. G

    A Black Hole information paradox and evolution in time

    I refer to a Schwarzschild Black Hole as the simplest example, and a well defined time outside the hole, say the Schwarzschild time. The information paradox of BH deals with the question of what stuff has fallen into the hole, but I am not aware that it deals with the question when the...
  20. Dennis Plews

    I The information paradox and non-locality, ER = EPR

    I heard recently that Dr. Maldecena recently commented to Dr. Susskind, regarding the black hole information paradox, that ER = EPR. Can anyone illuminate this for us mere mortals? It seems to link all information via non-locality, which has interesting implications.
  21. O

    A Conservation of Information: Neutron Formation and Decay

    Has anyone analyzed the process of Neutron formation and decay from the perspective of "information conservation"? Does anyone have any thoughts on what the results of such an analysis would be? What is the status of the observed evidence of reality in respect of whether one should conclude...
  22. A

    What is the core problem of the information paradox?

    Can you please explain what the core problem of the information paradox is? Hi all! I've read many articles about it, watched videos, argued with some physicists, and yet I can't grasp at all where the paradox lies. For example, from the Wikipedia: "An important difference between the black...
  23. anorlunda

    Is Information Truly Conserved in Black Hole Dynamics?

    Searches of PF archives for Information Conservation turn up many threads in which the question is more or less dismissed. It sounds like many PF regulars don't believe in it, as if it were fringe science or metaphysics. Contrast that with the prominence given to the recent thread Stephen...
  24. stevendaryl

    Connection between Einstein-Cartan and "Baby Universes"

    The Einstein-Cartan theory is, to my mind, a completely straightforward generalization of General Relativity, and indeed seems like a necessary generalization if we are to accommodate particles with intrinsic spin. (The mathematics for this claim is beyond me, but the layman's summary is this...
  25. ShayanJ

    Information paradox, dismissed?

    One of the important problems in modern physics is BH information paradox, which is the problem with non-unitarity of Hawking radiation. But now there is this paper which says that this process is actually unitary and so BH information paradox is, not solved, but dismissed. I'm posting this...
  26. Larry Pendarvis

    Is it possible to distinguish between pure and mixed states?

    Is it possible, in principle, for an experiment to distinguish between an ensemble of pure states and an ensemble of mixed states? If so, how? In particular, I am thinking of an ensemble of particles whose spin has been measured, one at a time, on the "Vertical" axis. The ensemble consists of...
  27. K

    The Hawking radiation and information paradox

    Here is my understanding, please correct me if I made any mistake Quantum physics theory suggests that information (the wave function, state, etc.) cannot be destroyed. All matters fall into a black hole will not be able to escape, which means all information of these particles stay inside...
  28. O

    Black Hole Information Paradox and Alcubierre Warp Drives

    Suppose Alcubierre warp drives or some alternative form of warp drive is possible. Then surely a warp drive could enter the event horizon of a black hole, observe the interior, and exit the horizon, returning with information from within the black hole. What about black holes never visited by a...
  29. G

    Black hole information paradox?

    Would it be possible for a black hole to carve a trail of information on two dimensional space in the holographic universe? Could the black hole, acting as a conduit between the macro and micro universe, due to its properties at the singularity (at the plank scale) carve the the information...
  30. A

    Black hole information paradox

    I watched this documentary about an argument involving information loss in a black hole, Stephen Hawking managed to wind everybody up by claiming information was lost and therefore broke existing laws of physics. Its an old recording so it may not be relevant anymore but one part of this...
  31. A

    Curious about Black hole information paradox

    Hi! I am not much of astrophysicist or something but read something about Black hole information paradox in a book. Could anybody please explain me what is the meaning of term and why does it happen? P.S. Please include Hawking's radiation as well Thank you in advance
  32. Islam Hassan

    Question re the Information Paradox

    The black hole information paradox is resolved by considering that "...information is not lost in a black hole, but that all of the information of what is inside of a black hole can be viewed on the event horizon". As the black hole gets smaller and smaller through the emission of Hawking...
  33. P

    Resolution of the black hole information paradox

    What is the resolution of the black hole information paradox? According to quantum theory, information — whether it describes the velocity of a particle or the precise manner in which ink marks or pixels are arranged on a document — cannot disappear from the universe. But the physicists Kip...
  34. G

    Does life present any information paradox?

    This question might rather be posted in Biology but since the information paradox is usually the subject of black hole physics I thought physicists may be better placed to answer it. The fact that information may be lost in black holes is considered a paradox, information is believed to be...
  35. C

    Information Paradox: How a Drawing Can Represent Two Things

    As far as I know, net information content in the universe is constant. How about this: A child draws a simple skeleton of a house connected to another house with a pipe and draws a similar pair of houses right next to them with a fallen tree between the two houses. The second pair of houses...
  36. B

    Hawking, new theory on information paradox right or qwrong?

    Hawking, new theory on information paradox right or wrong? Does anyone have any views on Stephen Hawking amendment to his 30 year old theory of black holes and the *information paradox that was recently challenged? Once past the event horizon information is lost forever and only the energy...
  37. S

    The Susskind Counter Information Paradox?

    The Susskind "Counter Information Paradox? Recent programme here in the UK deals with the "Hawking Paradox",: http://www.bbc.co.uk/sn/tvradio/programmes/horizon/hawking_prog_summary.shtml The programme has two opposing views on Blackholes, Hawking take and Susskind's take on BH...
  38. Fredrik

    Questions about AdS/CFT duality and the information paradox

    I have a few questions about something I read in the http://pancake.uchicago.edu/~carroll/hawkingdublin.txt of Stephen Hawking's talk at GR17. He says that it has been claimed that the information paradox can be resolved by a duality between supergravity in anti de sitter (AdS) space and a...
  39. X

    Did Hawking Solve the Black Hole Information Paradox?

    I heard Hawking gave a speech and theory and how the information paradox regarding black holes can be resolved. I am unable to find any information on this, and will be extremely grateful if someone were to summarise or post a link to a paper regarding this.
  40. O

    Is Gravity the Pure-Vacuum SINGULAR state?

    May be absorbing 3-D information, but they can only emit 2-D information. According to Hawking recent expose on 'Information Paradox', the result conforms to the reality that Blackholes at all Galactic cores are really Nature's Parametric Low Energy Dimensional Down-Converters. For every...