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I The speed of decoherence

  1. Mar 1, 2017 #1
    Does anyone know or know of the general predictions of the speed at which of coherent system losses coherence to contact with a decoherence system? Is that speed limit faster than the cosmic speed limit?
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  3. Mar 1, 2017 #2


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    I assume you mean c, the speed of light. There is no "cosmic" speed limit due to the expansion of spacetime (which is something of a monkey wrench in the concept of a limit). There are objects that are receding from us at over 3c (I think, it has z>11), for example GN-z11.
  4. Mar 1, 2017 #3


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    Decoherence does not occur at a specific speed. It depends on a number of factors. Generally, it would be well less than c.

    A couple of the others here know quite a bit about the subject, and could answer more detail follow-up questions you might have.
  5. Mar 1, 2017 #4
    Light moves at the cosmic limit, but c describes more than just photons. The speed of light isn't technically what c is, is just happens to be equal to it. Spacetime does expand faster than light, but it still does not violate the cosmic speed limit which is a proper termonogly when taking about c. The cosmic speed limit is the limit at which particles move through spacetime, however c does not hinder the movement of spacetime itself.

  6. Mar 1, 2017 #5
    There is a concept know as scrambling where entanglement effects propagate through a tensor network. There are fast scramblers and slow scramblers but there is a limiting speed at which information can travel through the network.
  7. Mar 1, 2017 #6
    And i suppose that speed limit is less than c? Making that assumption based on the idea that the particles must need to be able to move close enough together using classical physics before they could adapt the ability to utilize entanglement effects that could affect the system? Does what I said sound intelligble? Lol I am actaully just a car salesman with the hobby of phyiscs but trying to wrap my mind around properties of coherenece.
  8. Mar 1, 2017 #7
    I don't know enough about this to make any further comment, I just thought it may be relevant reading material for you, I'm not even sure if it is relevant.

  9. Mar 1, 2017 #8


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    Yes, that's not a bad description for where you are coming from. There are all kinds of classical/semi-classical effects occurring in the environment that lead to decoherence. Thermodynamics (heat), for example.
  10. Mar 1, 2017 #9
    It was helpful actually! Thanks :)
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