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Observing the double slit experiment with ur eyes open or closed change the result?

  1. Sep 29, 2011 #1
    I know dumb question but If you observe with your eyes using a laser pen and two microscope slits does the wave collapse as opposed to closing your eyes while the light passes through the slits and then observing the defraction pattern on the wall?
    Also is it the measuring device that causes the wave to collapse like feynman states or is it the process of counsciessly observing the process. The kind of bull that tries to prove quantum counsciesness like what the bleep do we know?
     
    Last edited: Sep 29, 2011
  2. jcsd
  3. Sep 29, 2011 #2
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    AHHH now you stumble upon the million dollar question. Here is the problem: No one can answer that question. Try as hard as you can, a conscious observer HAS to become involved at some point. Even if you use a robot to take your readings, you eventually must observe the data the robot collects, which can cause wave function collapse. In essence, one can question whether or not the universe actually existed before it was consciously observed. It sounds insane, but it is an implication of quantum physics. One possible explanation is that macroscopic interference causes wave function collapse, but there is simply no known method to prove that, nor is there any way of defining when an object stops being quantum and can be considered macroscopic.
     
  4. Sep 29, 2011 #3
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    Please dont confuse people.

    It is not important if your eyes are closed or not. It is not important if observer is consious or not. As soon as quantum system interacts with any macroscopic (=thermodynamically irreversible) system, the information about the QM system 'leaks' into the environment, even if for all practicle reasons that information can't be recovered. When your eyes are closed, light interacts with your skin. This is enough.
     
  5. Sep 29, 2011 #4
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    Dmitry, this cannot be proven. If it could be, quantum mechanics would not be nearly as interesting as it is: Perhaps in certain circles within the field researchers believe "for certain" this or that. It is completely impossible, however, to know that ANY macroscopic system will cause a wave function to collapse. If Heisenberg's Cat could observe himself, then what fun would that be! While this is clearly a poor example, in all seriousness the wave particle duality would never occur if ANY macroscopic system could collapse a wave function. The presence of the detectors, the slitted shade, or even the ejector would collapse the funtion to a definite point and interference wouldn't occur.
     
  6. Sep 29, 2011 #5
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    TO BE CLEAR: I am not saying that collapse REQUIRES an observer, I'm saying that it could be argued either way. One difficulty that cannot be overcome is that, in order to perform any tests, a conscious observer becomes involved. We KNOW for sure that a conscious observer causes collapse. As to whether or not things would be different had the conscious observer not witnessed an event, we can NEVER know. (At least, not through experimental results, perhaps someday mathematical analysis can give us some insight)
     
  7. Sep 30, 2011 #6
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    Lets start from this: Copenhagen Interpretation with the 'collapse' thing is out of favour for at least 20 years now. Mysterious 'collapse' had been replaced with a well-studied and trivial 'quantum decoherence'. Quantum decoherence creates an appearence of collapse but contrary to it:

    * it is based on the unitary evolution, no mysterious changes propagating at superluminal speeds
    * no changes in physical systems based on the 'knowledge' of consious observers.
    * no role of consicousness. All you need is a body with a high number of degrees of freedom (most macroscopic bodies satisfy this condition)
    * no principal (and magic) difference between 'measurement device' which 'can collapse wavefunction' and macroscopic bodies that dont collapse wavefunction even they are big (glass, mirror, lenses). They are all made of the same atoms, aren't they? There should be no difference in QM!
    * no problems with the poor cat.

    QM is still weird, but that black magic had been, fortunately, gone (but left in most popular books)
    So there is no collapse anymore, except for some die-hard Copenhagen believers.
     
  8. Sep 30, 2011 #7
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    You are correct, the Copenhagen Interpretation is unpopular today. The reason for this is that many physicists, in my opinion, would like to sidestep the difficult questions that naturally arise from more advanced physics in order to have a more "productive" system. There is no corporate benefit in studying the nature of consciousness, which is an uncomfortable topic in most branches of science anyway. Quantum Decoherence DOES explain QM behavior without black magic, but it was also purposefully conjectured for that purpose(Kind of like when Einstein thought the Universal Constant made more sense than a finite, changing universe, though admittedly not that extreme)
    Thenewdeal38 has clearly stumbled across Copenhagen Island, and, though I probably shouldn't leave him stranded there, he is also entitled to learn about things from that perspective. I'll be sure to mention that there are differing perspectives when answering questions regarding quantum wave funtions and collapse in the future.
    -Eric
     
  9. Sep 30, 2011 #8
    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    Newdeal38 Please note: Dmitry is obviously very well educated on this subject, and has presented QD in a sad way that takes all of the fun out of it(simply because he understands it very well.) If you are interested in the more mechanical, less mysterious perspective, just know that its still pretty fun :) Even though wave function collapse has been "renamed" as decoherence, and described as....help me here dmitry...a loss of information...there are still wave functions and uncertainty in Quantum Decoherence. From this perspective they apply to the superposition of states, and the collapse, as I mentioned is called decoherence. I digress....my point is that Quantum Decoherence is fun and interesting too, though not nearly as existential or eye opening.
     
  10. Sep 30, 2011 #9

    Vanadium 50

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    Re: Observing the double slit experiment with ur eyes open or closed change the resul

    The OP has several different threads here, and neither are really about QM. The distinction between QM and woo woo has been made, and it's time to close these threads. If there is a question about actual quantum mechanics, it can be brought up here as a new thread.
     
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