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Beyond Schrodinger's Cat - a Television Appearance

  1. Sep 10, 2006 #1
    The following is my own expansion on Schrodinger’s original thought experiment, but taken to another level. It is envisaged here as something that might be carried out and verified.

    (Ethics demand that this should never be performed with a cat. It could easily be done with just the harmless decaying crystal. But for our purposes - as with Schrodinger’s original – the cat dramatises it perfectly.)

    OK, we have our sealed room with the cat. Inside is the radioactive crystal, which might or might not decay. If it does decay, lethal gas will be released and the cat will die. If not, the cat will live. Now, the point at which the cystal decays is said to be the moment when a wave function between two possible outcomes is created - not unlike that which occurs in the twin-slit experiment.

    In the twin-slit scenario, there is a superposition of states in which a single particle leaves evidence of having gone through both slits simulataneously, until it is actually detected. This has been verified. The superposition manifests itself as an interference pattern between the two possible outcomes.

    The Schrodinger set-up is no different in principle. If such a wave function does indeed occur, then before it collapses we have a similar superposition - the crystal has decayed and not decayed, gas has been released and not released, the cat is alive and dead. The classic quantum dilemma questions whether either situation - a dead cat or a live cat - is real unless somebody opens the door. As with the twin-slit experiement, it is claimed that both and neither version of reality exist until one version is squeezed into existence by direct observation.

    The challenge here is to find the equivalent of an interference pattern for everyone to see. How would an uncollapsed wave function in which the cat is both dead and alive manifest itself?

    In our version of the experiment, there is a television camera transmitting the event.

    Like the canister of lethal gas, the camera is linked to the radioactive crystal. What the camera does next will depend on whether the crystal decays.

    The camera is designed to transmit on two possible frequencies, A or B. Its default setting is to transmit on Frequency A. If the crystal does not decay, nothing will change. If the crystal does decay, it will switch circuits and transmit on Frequency B.

    Outside the room, the possible outcomes are ready to be witnessed on two monitor screens - respectively A and B.

    If the crystal does not decay and the cat lives, this will be seen and recorded on Monitor A.
    If the crystal does decay and the cat dies, this will be seen and recorded on Monitor B.

    There is no other communication between the room and the outside world. All observations are limited to television wave transmissions.

    The crystal has not yet passed it’s random crisis point. Not surprisingly, we get a transmission on Monitor A. The cat is alive and well. Monitor B is blank.

    The crystal now passes it’s random crisis point. Here is what happens.

    Our expected wave function of two possible events occurs inside the room. Such a wave function is normally collapsed by direct observation. However, the only source of information is itself nothing more than a collection of wave transmissions. Consequently, the wave function, which includes both outcomes, does not collapse. Instead it is manifested as an interference pattern that incorporates the two possible wave transmissions. They are both faithfully sent on their respective frequencies – one to each monitor.

    On Monitor A, we see the cat live.
    On Monitor B, we see the cat die.

    We are now in live contact with different versions of what night have happened inside the room. The two transmissions continue for as long as the room remains sealed.

    When the door is eventually opened, the wave function collapses to a single transmission. One of the monitors goes blank while the other continues to show it's version of events. This is of course the version that corresponds to the reality encountered when the room is unsealed.

    Nevertheless, we can play back a recording of the alternative version on the other monitor.

    This concludes the experiment.


    Can quantum interference take the form of overlapping TV signals that split in this way?

    Most theorists now adhere to the Many Worlds view of quantum mechanics. However, if something like the above experiment were succesfully carried out, some might find it consistent with the Copenhagen Interpretation.

    From the Many Worlds view, the two transmissions would represent equally legitimate realities that branch off into separate universes once the room is unsealed. With the Copenhagen Interpretation, neither transmission represents any reality and unsealing the room is what forces a version of events into existence.

    Views are welcome

  2. jcsd
  3. Sep 10, 2006 #2
    Firstly, the reason we see the interference pattern with 2-slits and the reason we don't with the standard Schrodinger's cat scenario is because the former pattern arises after a large number of events, whereas the latter is (usually) a singular event.

    The "collapse of the wavefunction" has little to do with observation. Instead it appears to occur when a quantum system interacts with another system that has large (i.e. classical) degrees of freedom.
  4. Sep 10, 2006 #3


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    This won't work because using a camera is equivalent to directly observing the events in this case.
  5. Sep 11, 2006 #4
    Actually Masudr, the interference pattern has been witnessed in the twin-slit experiment after only a single particle has been fired. This has been tested.

    It happens without fail, every time there is more than one possible route a particle can take, but only when there is no direct observation of which slit is entered. Until such observation, the particle becomes a wave of information - not unlike a radio or tv signal. This wave informs us that a single particle has gone through both slits simultaneously - with no ifs or buts. However, once the slits are monitored, the wave function collapses to a single path taken.

    Alkatran, tv and radio signals are, by their nature, a series of wave functions by which information is transmitted. If you see a live image on your screen of me in London, it wont be because of any matter or energy that travelled from me to you. The same goes for all the millions of others who might see me. Instead, the existing matter and energy at your location is receiving instructions on what form to take. The wavicle nature of this communication means you are seeing and hearing a represention of me, but this is not direct observation. Why not? Because the light and sound that comes from your tv did not originate from London.

    The same applies to the above experiment. Since the relaying of information from inside the room to the two monitors takes the form of wave transmissions, I'm proposing that information about the possible outcomes will be preserved and transmitted accordingly. The two images together are an interference pattern - no different in principle to what occurs in a twin-slit experiement. It is simply that this interference takes the form of tv signals.

  6. Sep 11, 2006 #5


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    I think you're missing a zoo of experimental observation here to test our your hypothesis. In particular, you need to pay attention to Delft/Stony Brook experiments on the Schrodinger Cat-type states producing the coherence energy gap. You are ignoring the fact that an observation of one observable does NOT collapse the superposition of a non-commuting observable.


  7. Sep 11, 2006 #6

    Doc Al

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    Not true. A single particle passing through a double slit would only make a single "dot" on the screen--hardly an interference pattern. (Perhaps you are thinking of experiments wherein only a single particle passes through the apparatus at any given time. It still takes many, many particles passing through the slits to build up a recognizable interference pattern.)
  8. Sep 11, 2006 #7
    The wavefunction (a complex quantity), which carries the interference pattern, is never observed.

    A TV/radio signal is an EM wave. Classically speaking, it is a fluctuation in the EM field. A wavefunction is a completely different beast.

    Actually, it is energy, in some cases amplified, in the form of photons to the film/CCD screen, electron wave through wires/photons to&from satellites, photons to antennae, electron waves through wires, electrons through CRT, photons to eye.

    Once the cat has interacted with a large classical system, it becomes an eigenstate of some sort.
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