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Quantum Particle - Spread Throughout the Universe

  1. Aug 26, 2012 #1
    Hi there,

    In Brian Cox’s book “The Quantum Universe” he states that after t=0, a quantum system is everywhere in the universe.
    Does this apply to all situations (experiments, etc.), and both micro and macro objects? If so, in delayed-choice entanglement swapping experiments we deliberately delay photons reaching detectors until other photons are registered. But if the above paragraph is true, wouldn’t the photons already have reached the detectors if they are to be anywhere else in the universe? So sending photons along a longer fibre optic cable, compared to other photons, doesn’t really delay them at all? Unless I’m missing something…

    Cheers for any clarifications.
  2. jcsd
  3. Aug 26, 2012 #2

    I'd say you are onto something. I would say that observations affect outcomes and force fields to behave classically, so even if the 'particle' is everywhere, its classical manifestion(observation) will appear to obey delays, distances, etc. I consider time to be an emergent phenomenon at larger scales and this isn't as crazy as it sounds. We have to remind ourselves from time to time that the physical stuff is a peculiar form of energy, so we can't force our classical-like concepts onto something that is so fundamentally a-classical and expect it to be perfectly classical at all levels and all circumstances. It's such a miracle that there is some form of classicality at all, given that you wouldn't be able to tell even if you had all the knowledge of quantum physics nowadays had you not witnessed it first-hand. Quantum physics does not appear to describe a classical universe, but a probability of a classical universe that is otherwise in a state of superposition. I know what your next question might be, and i am genuinely wondering the same thing.
    Last edited: Aug 26, 2012
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