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

Virtual particles and entanglement

  1. Jul 8, 2003 #1
    Are virtual particles entangled when they appear? If so then when one of the pair falls into a black hole and other flies off, do they remain entangled? If so, does this mean that by observing blackhole radiation we can in principle 'see inside'?
  2. jcsd
  3. Jul 8, 2003 #2
    I should assume so, though I have no reference to substantiate my assumption. If a photon temporarily becomes two particles, then those must be "entangled" - or so it appears logical to me.

    It would appear so, but I thought that virtual particles anhialated (sp?) themselves in an "instant", and thus one would not fall into the BH without the other, would it?

    I don't know. Blackhole radiation has always confused me (as you can see from my (above) previous question).
  4. Jul 8, 2003 #3

    Yes, according to Hawking at least, those pairs that emmerge right at the edge of the BH's event horizon are split, one falling into the black hole and the other spirialing out. These extra particles are what make up black hole radiation. I find it interesting that there's actually matter here coming out of nowhere! Seems to me that BH's suck in more than they put out probably though (just a guess).

    Here's a tangent thought...

    As many know, gravity is the weakest of the fundamental forces. Now, the only thing that gives a black hole that event horizon is that it's escape velocity is greater than c. Seems to me, that if you used MAGNETIC force (a lot stronger than gravity), that you could create conditions where an object would have to be moving at greater than c to get away from the pull. In effect, you'd have a "greater-than-c escape velocity", only based on magnetism instead of gravity.

    Now, if you could somehow charge a fluctuating vacuum quick enough to be reactant to your magnets, couldn't you create a force strong enough to rip apart virtual particles at this artificial event horizon? Thus, you'd be creating matter out of nowhere. Of course, my guess is that the mass-energy expended to get x amount of material is more than the mass-energy of the material. But it would still be cool to do (like when they turned lead into gold, even though the cost of doing so was more than the gold was worth).

    ok sorry, shoulda made a new thread for that. But as for still being entangled, I really have no idea. I would imagine that all we would "see" (i.e. calculate backwards) if we could would be a bunch of the other particles smushed into a point.
  5. Jul 9, 2003 #4
    To my knowledge, particles are not 'entangled' in any way. They annihilate with each other VERY quickly and are not much apart, that's all.

    It's true that one of the particles might fall into a black hole. It's almost always the negatively charged particle (cannot remember why), and the gravitation of the black hole is powerful enough to somehow make it into a 'real' particle.

    Nothing really comes out of the black hole. It SEEMS something is coming out because the black hole's mass is a bit smaller (negative energy was brought into it, remember?) and there is a new lone particle in the space, but it isn't that the particle has come out of the black hole, it's just that the negatively charged particle has gone in.

    Tiberius, there is no matter coming out of nowhere, because there is also antimatter with it, so the general amount of matter stays the same.
  6. Jul 9, 2003 #5


    User Avatar
    Science Advisor
    Gold Member

    Yes of course they are entangled, the clear example of this is when one falls into a black hole.
  7. Jul 9, 2003 #6


    User Avatar
    Science Advisor
    Gold Member

    Black holes do have negative energy flowing into them, but this is an absolutely minute quanity for any decent sized black hole compared to the amount of postive energy flowing into them.

    No escape velocity is only a function of the gravity of an object not for example the strength of it's charge.

    In a balck hole you already have regions were the escape velocity is greater than c but these lie beyond the event horizon.
  8. Jul 9, 2003 #7
    well, my main interest was reasoning that if escaped particle has reached us, it has quite large chance of having not interacted with anything, thus it could include sort of information about its entangled partner. no?
  9. Jul 9, 2003 #8
    Well, this is probably true, but for all practical purposes I don't think it could happen. I say this because it still hasn't been shown to me that a virtual particle actually continues existing, after it's partner has fallen into a BH. Seriously, the virtual particle (according to Feynmann's hypothesis) to all of the possible paths into the BH, and some of those paths lead it right back into the vicinity of it's partner, where they would annihilate each other.
  10. Jul 9, 2003 #9
    But whether matter or antimatter, you still have more particles than you had before, even though some are matter and some are anti-particles. The two are not cancelling each other out. In fact, even if they did, then there would be the energy from the particles and antiparticles mingling. Is short, SOMETHING is coming out of nowhere with black hole radiation or else there wouldn't be something to be given that name.

    So, as I understand it, in a vacuum you have pairs of particles constantly appearing and cancelling each other out. Then on the edge of an event horizon, where the pair appear and strattle that line, one of the particles is "sucked in" so to speak, and the other then is left behind and NOT cancelled out. In some of these pairs, the anti-particle is left behind and the matter particle falls in, and in others the opposite is true. The result is that gozillions of matter AND antimatter particles are radiating away from the black hole, virtually from nowhere. Even antimatter has mass (it doesn't have NEGATIVE mass) so the total mass-energy has increased.

    Am I misunderstanding something about this anyone?
  11. Jul 9, 2003 #10
    One science correspondent recently reported that he had made serious enquiries as to why Hawking's has never received a Noble Prize. The answer was that none of his (Hawking's) work could be related to reality. One should take purely theorectical work with the same caution shown by the committee.
  12. Jul 9, 2003 #11
    I think you're interpreting that response wrong. The comment about not relating to reality is not a snide remark that addresses the reliability of the work in any way. Rather, what they mean is more likely that there are no direct applications of the work at this time. For example, Einstein did not win a Nobel prize for his well known and appreciated Relativity, but rather for the Photoelectric effect. Although, in the larger scheme of things, relativity will be better remembered as an "eye opener", the photoelectric effect had immediate and direct applications in inventions. The Nobel prizes seem to favor work that has immediate and direct practical application, and perhaps that's as it should be. But to take their comments as relating in any way to the reliability or soundness of the theories is misguided I think.
  13. Jul 10, 2003 #12

    Whatever are you talking about?

    Please do explain!
  14. Jul 10, 2003 #13


    User Avatar
    Science Advisor
    Gold Member

    If one falls into a black hole, the other one will instantly become a real particle.
  15. Jul 10, 2003 #14
    Actually, it's free to interact with whatever it wants once it has escaped. And what information are you hoping to receive?
  16. Jul 10, 2003 #15
    Actually, both of them will, and that doesn't mean they are entangled. It's the black hole's gravitation that turns them into real particles, not the fact one of them falls into the black hole.
  17. Jul 10, 2003 #16
    Just like you have more numbers if you have -1 and +1, but it's still 0...
    Yes they are.
    True. But the particles don't REALLY come out of anywhere, their birth is strongly connected to the fiels that are in the space...
    The name just implies the hole radiates - meaning, it becomes smaller and there are particles coming out of its vicinity. Something coming out of nowhere would violate some laws of energy conservation or whatever they are called.

    That's right, although you were saying the exact opposite of this a few sentences ago...
    Right, but don't forget that the antiparticle that went inside the black hole 'cancelled' out some particle there...
    Let me assure you that's far less probable (I can't remember what it is, but I've read several times that particles with negative energy have a far greater chance of getting 'sucked in').
    Here's where you're wrong. There is a particle and an antiparticle, and the antiparticle has NEGATIVE energy. That's the whole point. It's like in simple mathematical equations - you can add 1 to anything if you also subtract 1. +1-1=0. The whole point is that one has positive and the other has negative mass/energy.
    :wink: Questions?
  18. Jul 10, 2003 #17


    User Avatar
    Science Advisor
    Gold Member

    No, Tail they DO NOT both become real, the particle that fulls into the hole represents negative energy flowing into the black hole.

    The black hole's grvitation makes one of the pair become a real particle due to the fact that it accretes one of the pair.
  19. Jul 11, 2003 #18
    Is it free? What happens with escaped particle when fallen antiparticle annihilates with some matter inside BH? Would entangled particle receive all properties of that its pair encountered?
    Initially, "there was" 1 particle (in BH), then, pair appears, total 3. One goes off to earth, other falls into BH where it interacts with its destined one. End-result - 1 real particle on way to earth. If conservation laws hold, then it must have all properties of initial particle inside BH?

    I don't hope anything practial about that info. Still, some remote estimates about BH-internal environment could be extracted in principle, i guess. Thus some observational evidence.

    Also, I recall there was some issue with BH's information loss. I thought those entangled pairs might be related, but haven't heard anything on that.

    If I think of abstraction where only instant is viewed when anti-energy interacts inside BH, that happens after it has traveled some distance into BH and its matter-pair has traveled away, then picture arises that energy of poor particle inside BH effectively travels at 2c to outside...
  20. Jul 11, 2003 #19


    User Avatar
    Science Advisor
    Gold Member

    Basically a measurement on one of the virtual particles defines the properties of the other so they are entangled.
  21. Jul 11, 2003 #20
    Does annihilation qualify as 'measurement'?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Virtual particles and entanglement
  1. Virtual particles (Replies: 0)

  2. Virtual particles (Replies: 9)