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Antiparticles vs virtual particles

  1. Dec 5, 2011 #1
    Im a grade 12 student and I just started reading black holes aint so black in the brief history of time. However, I'm having a hard time distinguishing a difference between these two particles. What is a difference?
    thanks!
     
  2. jcsd
  3. Dec 5, 2011 #2
    I'm not exactly confidant on all matters concerning this subject, but I do know that if two particles; one of virtual and one of anti matter, they would each be destroyed in a release of cosmic energy. Also an item (like a space ship) made of anti matter could exist in the vacuum of space, only as long as it doesn't come in contact with any virtual particles.
     
  4. Dec 5, 2011 #3

    Ken G

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    Virtual particles have a formal meaning to quantum field experts (though they debate what that meaning ought to be), of which I am not one, but it sounds like you are interested in a much more informal meaning of the term, as appears in some explanations of Hawking radiation. Antiparticles are real particles, established in the laboratory, that have positive energy (despite the "anti"), so can only transport positive energy from place to place. But the energy of virtual particles does not show up in the final tally at the end of whatever process is under study, because virtual particles are never there at the end, so they can transport negative energy (temporarily). So if an object gains energy, we can say it absorbed a virtual particle that gave it positive energy, or we can say it sent out a virtual particle that contained negative energy, so long as that virtual particle is not still around at the end (so it must give up that negative energy to something real that ends up with less positive energy). That's the picture used in Hawking radiation-- two virtual particles are produced (generally virtual photons), and one goes out and becomes a real photon with positive energy, and the other transports negative energy into the black hole before it blinks out of existence. It doesn't matter which is the particle and which is the antiparticle-- it could be either. What matters is that the particle that comes out must turn into a real particle, so must have positive energy, but the one that goes in is lost into the black hole, so it does not need to become a real particle and can transport the negative energy that allows the energy budget to work out when its entangled pair particle becomes real.

    I should also mention that few experts hold that this is a formally correct explanation of Hawking radiation-- it is more like a useful picture of uncertain reliability that is thought to be more suitable than giving a bunch of detailed equations.
     
  5. Dec 6, 2011 #4

    mathman

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    Virtual particles are the effect of quantum theory being applied to the vacuum. They pop into and out of existence in pairs, so there is no change in conservation laws. They may be a particle antiparticle pair or a pair of photons.

    Antiparticles are real. The most common in ordinary usage are in PET scanners.
     
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