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

A electron can exist in everywhere ?

  1. Nov 14, 2012 #1
    Hello all .
    In quantum physics there are any theory that says a electron or Partial of electron exist in everywhere in universe ?
    Means a electron in other side me can exist Partial of it in 300000 light year ?
  2. jcsd
  3. Nov 14, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    There's no such thing as a part of an electron, not according to the commonly accepted (textbook material) theories.
  4. Nov 15, 2012 #3


    User Avatar
    Science Advisor

    The wave function of an electron can exist everywhere. But the observed position is just in one spot. The electric field from the electron also extends indefinitely far in its light cone.
  5. Nov 15, 2012 #4
    Quantum superposition states that a physical system, in your case an electron, exists in all of its possible configurations simultaneously. However, when observed or measured, the results of the measurement correspond to only one of the possible states.
  6. Nov 15, 2012 #5
    Particles being everywhere - is this a compelling reason to question that the world might be fake and not real?
  7. Nov 15, 2012 #6
    Not really, I don't really see the connection, lol :D
  8. Nov 15, 2012 #7

    Particles being everywhere at once. This isn't the world we encounter daily, is it? Particles are supposed to have positions and velocities, or at least that's what my experience so far suggests.
  9. Nov 15, 2012 #8


    User Avatar
    Staff Emeritus
    Science Advisor

    The particles are not everywhere at once. The WAVEFUNCTION, which is a mathematical formula used to predict where the electron MIGHT be, says it has a range of locations. This does not mean that the electron will be in two places at once. If you interact with the electron, it will only be in one place at a time.
  10. Nov 15, 2012 #9

    Aren't wavefunction and particle 2 aspects of the same thing?
  11. Nov 15, 2012 #10
    So what you mean is that what we observe is actually not real, but some underlying world is?

    No. A particle (or a group of particles) has a wavefunction. I think you're getting confused because people talk about wave-particle duality, wherein particles display both particule and wave behaviors. However, particles in quantum physics do not have the same meaning as in classical physics (very tiny solid objects) and a wavefunction isn't a classical wave either.
    Last edited: Nov 15, 2012
  12. Nov 15, 2012 #11

    Are you claiming that the wave nature of particles is a myth? What exactly are you saying - that particles can behave as waves but the wave nature isn't real? That makes no sense, you are contradicting yourself. Either the wave nature of particles is real or it isn't. For consistency reasons, you can only choose one not both and argue both ways.
  13. Nov 15, 2012 #12
    No, I'm saying a particle (in the quantum sense of the word), can display both wave-like and particle-like behavior (in the classical sense of the word). A wavefunction is not a wave though.
  14. Nov 15, 2012 #13


    User Avatar
    Staff Emeritus
    Science Advisor

    He said nothing of the sort. The wave-like properties of an electron are because of the wavefunction. (Or rather, the wavefunction is because the electron has wave-like properties) But you cannot say that the particles is located everywhere that the wavefunction says it might be at, because when we measure it we only detect it in one place.
  15. Nov 15, 2012 #14
    You are both not addressing the question i raised.

    "because when we measure it we only detect it in one place. " ...doesn't address the issue of whether particles and reality exist at all times and esp. before detection. The fact that an electron is calculated and verified experiemntally to behave exactly according to qm rules suggests that the electron is in all of its possible positions. Or if you argue that the wavefunction isn't real, then only detections are real(reality isn't real), which is the same answer just coming from the opposite direction.
  16. Nov 15, 2012 #15
    That's just not true.

    Moreover, an electron can exist before you detect it, and it can be in a superposition of states, which doesn't necessarily mean that it 'exists several places at once'.

    G-sound, bear in mind that we cannot measure or otherwise observe the wavefunction itself, it is not a physical object, it's a mathematical abstraction from which we can extract information about the current state a of a particle or sytem of particles.
  17. Nov 15, 2012 #16


    User Avatar
    Staff Emeritus
    Science Advisor

    This has nothing to do with "reality existing". No matter what our theory says it's obvious reality exists, even if we describe it incorrectly.

    As to whether the particle itself exists everywhere at the same time is...complicated. First, we would need to decide what that even means. To date I don't believe anyone has been able to come up with an accepted interpretation of what the wavefunction means in a non-mathematical way.
  18. Nov 15, 2012 #17

    When it acts as if it's in all possible states at once in the universe, and some pretty complicated machinary depends on this wave nature of electrons, what does it say about the world?
  19. Nov 15, 2012 #18

    I'd say you are right that it exists though I am far less certain how and when it does.
  20. Nov 15, 2012 #19


    User Avatar
    Staff Emeritus
    Science Advisor

    That the particle obeys the mathematical laws developed by QM. That's it.

    Please, leave ramblings on reality out of this thread. They don't pertain to the thread at all and only serve to confuse people.
  21. Nov 15, 2012 #20

    It never acts (it is never seen, or measured to be) as if it were in many different states at once. That's one of the founding concepts of quantum mechanics. Whether the particle actually is in superposition of states when it is not observed is a question of philosophy. I still don't see how this has anything to do with the reality of our world, because that electron is still real, whether it is in a superposition of states or not.
    Last edited: Nov 15, 2012
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook