To Crunchy Cat also. That is false. The cat, even the fleas on it, are entirley classical, not quantum objects, at all times. What you say is no more true than if I were to use a coin flip to decide whether or not to drown the cat and claim it is in a mixed state until I look to see if coin came up heads or tails. neither the quantum nor this classical decission process about it living or dying changes the fact that the cat (and its fleas) are much too massive objects to be treaded as mixed state quantum objects. SUMMARY: Cats are always classical objects. Never a set of mixed quantum states.
Something worth considering: Does the cat constitute an observer in this experiment? What if it were the experimenter that was in the box?
The cat in a box mind experiment brings to my mind the discussion of particle wave duality and reality. To me, particle wave duality is a fact. A single particle is cloaked in uncertainty if unobserved. That fact doesn’t keep me from expecting an object like a cat will be coherent at all times, whether it is observed or not. Interactions among particles that make up the cat overcome the individual particle uncertainties and establish the intact presence of that cat at all times. In that same direction, poison that would kill a cat that was observed would kill a cat that wasn’t observed too. Maybe I just don’t get the purpose of the mind experiment. Could you state what the point is and what the conclusions are?
You still do not understand that "observation" has nothing to do with any life form, even an ant, Looking. The word "observation" causes confusion in the ignorant. Replace it every where with "classical interaction" Repeating from my prior post 10: " An Observation occurs when the mixed quantum states particles interact with a “large amount” of matter. ("Large" meaning that the total energy, position, velocity, momentum, etc. of that matter are well defined simultaneously. For example, a driven golf ball has these well defined as a function of time and is in a “classical,” not quantum state.) For an example of 100 year old observations never looked at, not even by an ant, consider: Some of the glass plates covered with photographic emulsion film and carried high up in the atmosphere 100 years ago in cosmic ray experiments were developed, but not all were examined (processed by humans back then or more recently). The quantum events that classically interacted within these films were made into macro events (definite electron tracks etc in the film) 100 years ago. They are NOT still in a mixed quantum state waiting for some graduate student to look at them under a microscope. "
Billy, Gluon's assertion appeared to be a goofy way of saying that all the parts of the cat, everything outside of the cat, and basically everything part of the experiment has a relationship with each other and therefore each entity of the system acts as an observer; thus, a mixed state and human observation have no role in the experiment. This is especially important for two reasons. One is that it's true. Two is that this is a huge leap in gluon's thought process. When he first came to the forum as Reiku, he was on the pseudo/paranormal bandwagon of human consciousness being the sole collapser of a schrondinger wave. The post of his in this thread show that he has abandoned that foolishness and actually got something correct... humans play no role in the cat experiment. Additionally, while it's useful for people to work in a quantum and classic physics context, these aren't two different sets of real physics... it's all the same thing. In other words, the superpositions that can be observed with small particles very likely occur with large ones... they just collapse so quickly that they are presently beyond a human's ability to perceive them.
What if there were two cats in the box separated by a glass screen so that they could see each other? Then say that the experiment was rigged up so that if the particle was emitted, only one cat would be poisoned. For the cats inside the box, either one cat would be alive or both would be alive, but for the scientist outside the box, both cats would be half alive.
No, No, No! "Observation" is not in any way related to someone (even a cat) looking/ observing. Read post 10, 14, 21 & 24 - Only the ignorant are mislead by the word "observation" to think that some life form watching is what collapses the wave function. There is no shame in being ignorant - only in not learning when several times this has been explained. (As already explained in posts 10, 14, 21 & 24.)
Isn't the whole point of the experiment that we don't know if the gas was definitely released or not since we don't know if the radioactive particle was released?
Maybe I am as ignorant as Captain Kremmen (sorry Please Register or Log in to view the hidden image! ) but it seems everybody here is happy enough to conclude that there is no paradox because a cat is a classical object. The whole point of this thought experiment was so Schrödinger could show everybody that all the particles of a classical oject can (in admittedly strange circumstances) depend entirely on a quantum process - namely radioactive emission. if you believe (observed or not) that the cat is either definitely dead or alive then you must believe that the radioactive particle has definitely been released or not. Would this be right?
Would I be right in saying then that most people here believe in some form of objective collapse interpretation of quantum mechanics? http://en.wikipedia.org/wiki/Objective_collapse_theory
You have to account for the quantum event, with an observer who is not a quantum event. The cat is the stand-in, but a human observer who wants to know what the cat knows, has to open the box. We have to conceal the observation (from ourselves) but the cat can't tell us, in that case, when the event occurs. We see the 'dot' on the screen when it gets there, we can't say anything about when the the dot will appear, or where. But we can say that, given a large enough interval, an interference pattern will appear.
Yes, I think that would be right. Also, I'm thinking that to have a belief one way or the other would say that you don't agree with the Copenhagen interpretation. Would you agree?
that is the crux of the paradox, we're not sure if the cat is a conscious observer in itself. If the observer (us, or I) were placed in the box, the paradox would be meaninless because we would be sure of whether we see (or saw) the hammer falling and releasing the posion.
It doesn't matter if there is a conscious life form in the box or not. An observer in physics is any system capable of accepting information. That includes the box Please Register or Log in to view the hidden image!.
Would that definition go as far as to say that when particle interaction takes place, information has been accepted?
It seems that the process of emitting and accepting a photon in this case is a system and the whole system must be present for the process to take place. A suitable receptor is what we're calling an observer; if I'm getting Billy T's response correctly.
Yes, and so doesn't that say that the state of a particle is uncertain until there is an interaction like the accepting of a photon. The photon can be accepted by an electron and so the period of uncertainty for a photon would be the period from the time it is emitted to the time it is absorbed? If that is what we are talking about, then during that period the wave function rules, but when the absorption takes place the information has been accepted and uncertainty for that photon ends. Has the wave form collapsed into a transfer of information at a point in space and time where the interaction took place?
It seems that the photon does not depart until it has a suitable target. But then we wonder about how the photon "knows" there is a suitable target available.
