Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Holographic Principle question

  1. Jan 27, 2015 #1
    So I've been looking up things on the Holographic Principle for a while now, but there's still a few questions I have.

    As I understand it, the Principle says that if I drop a book into a black hole the book's information would be 3D inside the black hole and it would also be 2D on the event horizon.

    My question is, are there two books one 3D and the other 2D? Or is there just one book that is 2D and the 3D version is a projection that somehow emerges from the surface? In other words, when I drop a book into a black hole, is a copy created when it passes the event horizon or is there just one book in the entire system?

    If I'm unclear about this let me know. Also, I'm not a physicist so please keep answers layman.
     
  2. jcsd
  3. Jan 27, 2015 #2

    phinds

    User Avatar
    Gold Member
    2016 Award

    No, the book inside the BH has its information destroyed as it goes into the singularity. Well, that may not be quite right. The BOOK is destroyed but Hawking says the information is retained and comes out as Hawking Radaition.

    The 2D representation embodied in the holographic principle is, as far as I am aware, a mathematical fiction (strongly believed in by some, e.g. Lenard Suskind, who came up with the idea) that has no physical reality but which maintains the concept that information cannot be lost in the universe.

    I am a layman on this as well, so my opinion should be taken with a large grain of salt, and I readily admit that I think the concept is ridiculous.

    The black hole situation is one thing, because the event horizon of a BH, which not being a physical thing, IS a place where physical things happen (light emitted there, heading away from the singularity, just STAYS there, locally moving at c but globally hovering right there).

    On the other hand, the holographic principle also says (assuming that I understand it properly) that the information in the observable universe, for example, is contained on the surface of the sphere that defines the observable universe but that just seems ridiculous because the "surface" of the OU really IS just a mathematical representation of a place in space where nothing is happening. There is no physical reality to it. Also, MY observable universe has a completely different representational sphere than your OU, the two having centers that are at my right eyeball and your right eyeball (and this is assuming someone has poked our our left eyes).
     
  4. Jan 29, 2015 #3
    I thought you needed physical reality to have information. So the event horizon has no physical reality? How does the information exist on the horizon anyway? And is there a connection of some kind between the information on the horizon and the physical book inside? If so, what kind?

    I was also wondering how Hawking Radiation captured the information from the black hole (especially if there is no physical reality to
    capture). I get how black holes evaporate (on a layman's level), but not how the information is saved.
     
  5. Jan 29, 2015 #4

    phinds

    User Avatar
    Gold Member
    2016 Award

    The whole "information war" between Hawking and Susskind is way over my head and the Holographic Principle makes no sense to me so maybe someone who understands it better and believes in it will jump in and help you out.
     
    Last edited: Jan 29, 2015
  6. Jan 30, 2015 #5

    OCR

    User Avatar

    Lol... Ah, a work around that works... :oldeyes:
     
  7. Jan 30, 2015 #6

    OCR

    User Avatar

    You're quite right... :oldeyes:
     
  8. Jan 30, 2015 #7

    naima

    User Avatar
    Gold Member

    I think that the book in the black hole is not a good example. if we believe that information cannot be destroyed we may accept that the number of copies of a same information can decrease.
    The book has an author outside the BH or is on internet or somewhere else.
     
  9. Jan 30, 2015 #8

    phinds

    User Avatar
    Gold Member
    2016 Award

    I cannot understand your point at all and I think you misunderstand the issue. The existence or non-existence of an author outside the black hole has zero to do with whether or not information is conserved when something falls into a black hole. The information being discussed has nothing to do with anything that didn't fall into the black hole.
     
  10. Jan 30, 2015 #9

    naima

    User Avatar
    Gold Member

    the information falling in a black hole does not disappear if i have it in my library!
    There is only a problem if there is no copy.
     
  11. Jan 30, 2015 #10

    phinds

    User Avatar
    Gold Member
    2016 Award

    As I thought, you completely miss the point of the issue. I have already explained this in post #8. If you wish to believe in your own version of reality, that's fine, but it is the way it is. You misunderstand the concept of "information" in terms of physics and are incorrectly applying a very narrow English-language definition which excludes just about everything having to do with the book.
     
  12. Jan 31, 2015 #11

    naima

    User Avatar
    Gold Member

    A book is a macroscopic object on which you can read text or binary things like 1101
    I have a de finition of information. it is answer to questions. If i have two copies of a text i can find the anwer in one of those. If i concatenate them i get 11011101 which has the sameShannon information as 1101. if i throw one of the book in a Black Hole the remainig text has still the same information. Of course paper and ink is lost in the BH. I do not think that you confuse the media and the information. Maybe you think that i use a classical notion of information which "miss the point" and think that the answer is in quantum information.
    At the end you will have to explain how non vanishing classical information is recovered.
    I give you a definition of information as yes/no answers to a question which is asked to multiple copies of the same thing.
    Now it's your turn to define what is quantum information.
    Is it local? where is it in a Bell pair? Does not hesitate to be rigorous or technical.

    Thanks.
     
  13. Jan 31, 2015 #12

    phinds

    User Avatar
    Gold Member
    2016 Award

    I can't give you a rigorous definition but basically, it is everything about an object. The type, state, and arrangement of all the atoms that make it up for example. The "information" that you are talking about is utterly trivial by comparison, in terms of volume of information. And it is about THAT object, not some other macroscopically similar object.
     
  14. Jan 31, 2015 #13


    That's a good explanation of what information is. You can skip to 1:30 if you want.
     
  15. Jan 31, 2015 #14

    phinds

    User Avatar
    Gold Member
    2016 Award

    Seriously? UGH. That guy is a rambling bore more interested, apparently, in talking about himself than about science.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Holographic Principle question
  1. Holographic Principle (Replies: 16)

  2. Holographic Principle (Replies: 9)

  3. Holographic Principle (Replies: 5)

  4. Holographic principle (Replies: 17)

Loading...