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Decoherence in measurement apparatus

  1. Jan 16, 2016 #1
    I was wondering about decoherence:

    Suppose a measuring apparatus measures a single quantum property (say, spin). After the actual measurement of the property has taken place, the result 'decoheres' into the apparatus until the apparatus shows the measurement result, after which it decoheres into the world. At least, I am told such.

    I was wondering about the physical environment of the apparatus; the material the apparatus is made of is prone to numerous influences too. However, the measurement performed is kept separate from all these influences.

    My question is what the difference is between these two types of decoherence is in this context, and how the measurement is kept isolated.

    UPDATE: Considering this, it also occurred to me that after the measurement apparatus shows the measurement result, the result is propagating according to the 'environmental' decoherence again.
     
    Last edited: Jan 16, 2016
  2. jcsd
  3. Jan 16, 2016 #2
    I don't quite understand this part.... are you saying the apparatus undergoes decoherence before it measures the spin? You say measurement (edited from the word 'that') has taken place but then say "until the apparatus reads the measurement result". Reading a measurement having taken place, and if so from what?

    I think that when you speak of measuring the spin of an electron, it takes a very long time for the electron to be affected by decoherence. It is upon entanglement with the apparatus that both would undergo decoherence.

    Note edits.
     
  4. Jan 16, 2016 #3
    Sorry for the misunderstanding. I was wondering if I was using the correct terminology. I have rephrased it in 'shows' (in the readout of the apparatus). :wink:
     
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