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

I How many electron positron pairs are created

  1. Jun 10, 2017 #1
    How many electron positron pairs are created every second in a cubic meter of vacuum?
  2. jcsd
  3. Jun 10, 2017 #2

    Vanadium 50

    User Avatar
    Staff Emeritus
    Science Advisor
    Education Advisor
    2017 Award

  4. Jun 10, 2017 #3
    Don't these virtual partials pop in and out of existence in a vacuum?
  5. Jun 10, 2017 #4


    User Avatar
    Gold Member

    Google "quantum foam" and you'll see the speculative nature of that theory.
  6. Jun 10, 2017 #5
    Quantum foam does seem very speculative but aren't these particle antiparticle pairs responsible for vacuum fluctuations?
  7. Jun 11, 2017 #6
    The short answer is that you've been lied to. No theory describes the vacuum as that "sea of particles constantly popping into and out of existence" that popsci authors (and some overly romantic actual-sci ones) seem to like so much.
  8. Jun 11, 2017 #7
  9. Jun 11, 2017 #8


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    The vacuum state, by definition, is the one state in QFT which is absolutely stable, and nothing pops in and out of existence, because it's the ground state, the state of lowest energy. If there's no energy above the ground state there's nothing excited which could pop out of existence again nor can there be anything pop into existence spontaneously, because energy is conserved.
  10. Jun 11, 2017 #9


    User Avatar

    Staff: Mentor

    In normal language, the word "fluctuation" means "variation with time". In QM language, it's more like a synonym for "uncertainty" or "indefiniteness." Vacuum fluctuation does not involve variation with time.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted