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Knowledge of the superposition of states

  1. Oct 1, 2005 #1
    Is it completely impossible, even in principle, that eventually there can be a device by which we could know about the superposition of states without collapsing it?
    For example, being able to know that an atom is in a 30% probability of being unexcited and a 70% probability of being excited, without actually collapsing it in either of both states?
  2. jcsd
  3. Oct 1, 2005 #2


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    But there ARE already!

    All you need to do is measure a non-commuting observable. That's what the Delft and Stony Brook experiment did, by measuring the energy gap instead of the "current directions" in a superconducting junction.

    From a previous thread:

    Last edited: Oct 1, 2005
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