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

Lifetime & uncertainty relation w.r.t. particles

  1. Jan 25, 2007 #1
    Can anyone explain how to interpret Heisenberg's relation Delta(E)*Delta(t)>=hbar in case of "annihilation" and or "creation" of (elementary) particles:
    1) in case of virtual particles
    2) in case of antiparticles ?
    Is it eventually useful, if I may say so, to discriminate between the lifetime of the massive particle and that of its complementary energy quant ?
    If one could do so what would then be the consequence for the Heisenberg expression in either case?
  2. jcsd
  3. Jan 26, 2007 #2
    Background questions.

    I think it can be good to know the background questions I had when posting this thread, here the are.

    As far as I know all elementary “particles” have masses below the Planck-mass, thus their radius should be larger than the Planck-radius and be equal to the Compton-length which is inverse proportional to its respective mass. The Compton-length in fact is a quantum wave length. So my question could be, are not all these elementary “particles” to be considered as (Compton) wave packets, where it not that we are know with their dualistic (particle-wave) behaviour?
    If I consider light, then I now that it is a wave unless it is interacting, but as long as is does not interact I suppose its Compton-length is infinite if it has no mass. (If I take a 3000K Photon then I can calculate a very long Compton-length for it if I like). The dimension of a free electron also fits reasonably well its Compton-length.
    Applying Heisenberg’s relation ΔE*Δt ≥ ћ to elementary particles I remark that indeed their relative small energy/mass content gives them immeasurable long lifetimes in case that they have to “annihilate” completely (e.g. an electron or a proton). But then what means “annihilation”? According to conservation of energy I think it can not really be annihilation, so what kind of energy will result from such an "annihilation". I suppose it certainly will not be blackhole-mass which is far too unstable below the Planckmass? Candidates: zero-point energy, dark-energy, e-m energy?.
    Let me stop here, maybe I will come with more questions in case I get reactions.
  4. Jan 26, 2007 #3

    Gib Z

    User Avatar
    Homework Helper

    There exist several different interpretations of QM, and therefore the Uncertainty Principle. I myself can't say I perfectly Understand QM and think that its logical, i doubt many people can. Theres a good article here thatll help:

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook