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Probability Waves

  1. Jan 11, 2009 #1
    I have two questions about probability waves.

    Are we supposed to consider them as real physical waves, or are they just used to explain certain phenomenon? Should I consider them as real as the the earth itself?

    Does the probability wave collapse simultaneously in all frames of reference? If it doesnt then for an electron measured in California, could still be found in the center of the galaxy to an observer in motion relative to the earth, and what would happen if he did find it even though it had been found in California? Would there suddenly be two electrons? I thought that he couldn't find it because it had already been measured, but according to his frame (which is just as valid as any others) the measurment may not have happened so he could find the electron in the center of the galaxy, right?
  2. jcsd
  3. Jan 11, 2009 #2


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    From an operational viewpoint (my source of "should"s) how we use a probability amplitude wave i.e. a wave-function defines their meaning... and as such they represent what we know about how some quantum may behave. So in this sense, No they shouldn't be considered real. Others will disagree.

    Again from my operational viewpoint the cause of the "collapse" is our updated knowledge about the system and thus it is not a matter of frames but of our integration of that knowledge. In short the collapse happens on paper and not "out there".

    Edit: Take the analogy of the "collapse" of the value of a lotto ticket. Before the drawing it has an expectation value equal to each prize times the probability of winning the prize. After the drawing...or if you suddenly find out the drawing is fixed and know what if any prize the ticket will win then the ticket's value (as well as all other tickets' values) "collapses" into the expectation calculated from the updated information.

    This is one of the issues surrounding "interpretations" of QM and you'll find many many posts here debating the topic as well as much in the online and published literature.
    Last edited: Jan 11, 2009
  4. Jan 11, 2009 #3


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    It depends on what view-point one has regarding what is "real" and "existing" or not.

    Physics is a way to describe the world and what is in it. Does the number "2" exist? Do we invent or discover mathematics / physics?
  5. Jan 11, 2009 #4
    Thx for the replies. The lottery ticket analogy I thought was pretty cool way to put it :)
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