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Thread: How do Subatomic particles exist in two places at once?

  1. #1
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    How do Subatomic particles exist in two places at once?

    I've read that in a couple of places now. I figure it probably has something to do with particles appearing in pairs (within a vacuum) before disappearing an instant later.

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    Re: How do Subatomic particles exist in two places at once?

    Quote Originally Posted by Kebsis
    I've read that in a couple of places now. I figure it probably has something to do with particles appearing in pairs (within a vacuum) before disappearing an instant later.
    I too, read something a long time ago about a laser experiment with cesium. The laser was tuned to an "orange" wavelength and cesium atoms in certain states are affected by orange light.

    The laser pushed the atom into "two" where the "orange affected" state was displaced by a measurable amount, while the "orange-inal" atom reamined in the same state and was not displaced.

    Hope this helps.
    Solphe

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    Kebsis, are you referring to the theory that a particle and anti-particle appear in space and annihilate soon after? Or are you referring to particles that can have more than one quantum state? Or did I miss your point entirely?

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    Quote Originally Posted by The Supreme Canuck
    Kebsis, are you referring to the theory that a particle and anti-particle appear in space and annihilate soon after? Or are you referring to particles that can have more than one quantum state? Or did I miss your point entirely?
    I'm not sure if what I heard is either of those two theories, Canuck. It was simply explained to me as 'In a vacuum, particles appear in pairs (apparently out of nowhere), and in a fraction of a second they move towards each other, touch and disappear.

    I heard the subatomic particles being able to occupy two spaces at once thing elsewhere, and suggested that maybe the two ideas where connected. I'm sorry if I'm not being very clear.

    PS-it's late now and I have to hit the hay, but tomorrow I'll try to find a link to the site which mentioned it.

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    I believe you are referring to Feynman's formulation of quantum mechanics.
    In fact he states that particles must be viewed as travelling from one location to another along every possible path and so a particle could be everywhere at once? Sounds rather strange though. But then quantum mechanics is rather wierd.

    Pete

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    Quote Originally Posted by Kebsis
    Quote Originally Posted by The Supreme Canuck
    Kebsis, are you referring to the theory that a particle and anti-particle appear in space and annihilate soon after? Or are you referring to particles that can have more than one quantum state? Or did I miss your point entirely?
    I'm not sure if what I heard is either of those two theories, Canuck. It was simply explained to me as 'In a vacuum, particles appear in pairs (apparently out of nowhere), and in a fraction of a second they move towards each other, touch and disappear.

    I heard the subatomic particles being able to occupy two spaces at once thing elsewhere, and suggested that maybe the two ideas where connected. I'm sorry if I'm not being very clear.
    It appears to me that you're talking about two different things. The first is the production of a particle - antiparticle pair out of a vacuum energy fluctuation. These particles don't hang around for long as they usually recombine, annihilate, and disappear. The length of time they can last is given by the Heisenberg uncertainty relation delta E * delta t > h where h is Plank's constant (6.626 x 10 ^ - 34 J-sec). For an electron positron pair the required energy is about 1 MeV or 1.602x10^-13 J. This corresponds to a maximum duration of 4.1 x 10 ^-21 sec for the virtual pair. So, as you can see, the lifetime of these vacuum fluctuations is quite short.

    The second one sounds like a more recent result based on Bose-Einstein condensates. It relates to the behavior of integral sping particles (spin 1, 2, etc) at very low temperature (in the milliKelvin range). As I recall the experiment, when exciting the condensate with a laser, the phsyicists were able two split the wave function into two distinct places in space so that the particle was in "two locations" at once.

    (edited once to correct a stupid math error)
    "I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind." - William Thompson, 1st Baron Lord Kelvin

    "If it was so, it might be, and if it were so, it would be, but as it isn't, it ain't. That's logic!" - Tweedledee

    This isn't right. This isn't even wrong. - Wolfgang Pauli

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    The second one sounds like a more recent result based on Bose-Einstein condensates. It relates to the behavior of integral sping particles (spin 1, 2, etc) at very low temperature (in the milliKelvin range)
    If it's from BEC, that would be the nanoKelvin range. In that regime, milliKelvin isn't really considered low-temperature.[/quote]

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    Quote Originally Posted by Kebsis
    I heard the subatomic particles being able to occupy two spaces at once thing elsewhere...
    You may be thinking about the famous double-slit experiment in which a single particle passes through two separate slits and interferes with itself. This is an example of wave-particle duality. As a matter of fact this has been observed with objects as large as a 60 carbon atom buckyball molecule.

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    Ok, nK it is. ops: I'm a particle physicist, so this temperature thing sometimes leaves me cold. 8)
    "I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind." - William Thompson, 1st Baron Lord Kelvin

    "If it was so, it might be, and if it were so, it would be, but as it isn't, it ain't. That's logic!" - Tweedledee

    This isn't right. This isn't even wrong. - Wolfgang Pauli

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