Samirat post=18.73797.857123 said:
Lukeje post=18.73797.856098 said:
Samirat post=18.73797.856080 said:
Narthlotep post=18.73797.855717 said:
Nah, I like my quantum mechanics answer of it being more or less pointless to try to determine, as it could be the same dog occupying multiple locations at once. Though that then degrades into there might be only one dog, and the others are merely quantum madness, or there might be an infinite number of dogs occupying the same point in space-time.
Yeah, sure, that would be cool, if it actually worked. Fortunately, quantum mechanics has no place in the real world.
Keep telling yourself that... but the effects of quantum mechanics are actually all around us...
Edit: is this then the 1000th post in the thread?
Edit 2: you realise that quantum mechanics arises from statistics? The idea of MF being equivalent to FM relies on a 'superposition of states' much like Schroedinger's cat. We know that one dog is male, but not which one.
The key word here is quantum. Quantum mechanics is only relevant to mechanical systems close to the atomic scale. The Schroedinger's Cat problem occurs in a very different world from ours, and the situation is impossible to replicate in real life. It relies on a complete uncertainty that is only theoretically possible on such a large scale.
And probability such as this doesn't rely on "superposition of states." Superposition of states is the quantum mechanical explanation for probability. In no important way does Probability Theory rely on quantum mechanics. Superposition of states is merely an explanation for probability from the quantum mechanical perspective.
Wow, I can't believe this mess is still going on, but, speaking as a physics student, I feel I have to respond to this.
Quantum mechanics is, in reality, relevant at all levels, not just the small world of atomic and sub-atomic particles, just as Relativity is relevant on all scales, not just the large and fast. What happens is that the deviations from the classical theories for most "everyday" phenomena are usually below our ability to measure. Even so, there are many macroscopic phenomena that occur visibly, even on our classical/everyday level, that require the use of quantum mechanics to predict and understand(a couple of examples off the top are super-fluids and super-conductors).
Superposition is not just an explanation for probability in quantum mechanics; it's a very real occurrence. The easiest example to see superposition in action is the Stern-Gerlach experiment(look it up; I'm not going to detail it here).
However, there is an easier way to see superposition at the everyday level, and all it will cost is the price of admission to a 3D movie. The next time you go to a 3D movie, take 3 pairs of the polarized glasses they give you(just use the ones your friends or family get, cause I doubt they will actually give you extras). Take two of the glasses and hold the left-eye lenses up to each other so you can look through both. The rotate one of the lenses until you can't see all the way through anymore. At that point, the lenses should be oriented 90-degrees to each other. Now, take the third pair of glasses and insert the left lens of it between the left lenses of the other two. Then rotate the third glasses until its left lens is at a 45-degree angle to both of the first two lenses you used. You'll see something really weird happen: you're able to see through all three lenses! This is superposition in action.
The explanation is this: the lens of the 3D glasses polarize the light either horizontally or vertically(the left lens will polarize one way while the right lens polarizes the other way). Let's say, for the sake of explanation, the left lens polarizes vertically. So, with the first lens held normally, only lets through light that is vertically polarized. Normal light all around us has all kinds of directions of polarization and even has strange polarizations called circular polarizations(but these aren't important in this case). When the light passes through the first lens, all polarizations except the vertical polarizations are filtered out; so only the vertical polarizations make it through. When you take the second set of glasses and turn its left lens 90-degrees to the first, you make a horizontal polarization filter that only lets through horizontally polarized light. Well, the light from the first lens is all vertical, no horizontal components. So, no light gets through the second lens.
Now, here's where superposition comes into play. The third lens is at a 45-degree angle. So, it only lets through let that is has a 45-degree polarization. But, 45-degree polarization is composed of equal parts of vertical and horizontal polarization. Equivalently, you can say that vertical and horizontal polarizations are composed of equal parts of 45-degree polarizations(which include 135, 225, and 315 degree polarizations). Well, the vertical polarization from the first lens can be looked upon as being composed of equal parts of 45-degree and 135-degree polarizations. Well, the third lens lets through 45-degree polarizations, so half the light of the first lens gets through the third. By extension, you can then see that half the light from the third lens is able to make it through the second lens. Light makes it all the way through the three lens system and not the two lens system because of superposition of states(which are the polarizations).
In short, superposition of states is not a probabilistic view, it's a compositional view. The object actually is existing in multiple states simultaneously until you act upon it such to single at a particular state or set of states. In more technical language, we say that acting upon the wave-function with an observable operator collapses the wave-function to an eigenstate of that operator. In the example above, the observable operators were each of the polarized lenses from our 3D glasses, the eigenstates were the different polarizations, and the wave-function is the light itself. Notice that which eigenstates(polarizations) we used depended on the operator(lens) we used.
Now, in a real quantum system, you get things like decoherence and state evolution that may further change the mix of eigenstates in the wavefunction, even though a specific eigenstate may have been selected at an earlier time.
Sorry for the windy response, but I just felt the need to clear up that little bit of misunderstanding.