Okay, maybe some clearing up of quantum...stuff is needed.
Only if you are interested.
Quantum mechanics is the study of the excruciatingly small: no you can not properly imagine how small. At this scale, as it turns out, things don't work the way they do up here in the (relatively) large scale. Particles are the 'indivisible' units of the universe; in general they do not break down. You can't just rub two protons together and wear them away like you can with two blocks of wood or metal (or elves...).
Now, to detect the properties of such a small particle, since they are fundamental, you need to do something to it, that is, you must hit it with another particle or use some kind of field thing (since magnetic fields etc. are conveyed by particles in the first place, you can't escape hitting the thing you are studying with a particle). You must use a particle because you can not probe something with something of a grotesquely different scale. Looking at the properties of a grain of sand by throwing Jupiter at it isn't really gonna get you anywhere.
SO, the problem becomes this: let's say I have two particles: the subject and the probe. I intend to investigate the properties of the subject by, simply, throwing the probe at it and seeing what happens. Since both are particles, I do not really have any idea what state either is in until I witness some reaction. I truly have no clue what either is doing until I observe them interact: there is no initial state that I can be aware of, since to figure it out, I would need to probe the two particles with yet more particles.
Since I do not know anything about the two particles until they interact, it is as if they have all states at the same time. Since I don't know, the particles could be anywhere with any spin. So far this sounds like a philosophical line of thinking. "Sure, LZ, that is the case if you think about it. But c'mon, my glass certainly isn't anywhere in the universe, at any and all temperatures at the same time when I am not looking at it."
The argument is solid, yes, but it seems it should just be an argument, like Xeno's thought experiment where he proves motion is impossible. To move 1 meter, I must move half of it first, to move half of it, I must move .25 meters first, etc., resulting in the 'fact' that I will always have to have already moved before I move. Without the idea of the mathematical limit, Xeno is right. It seems there should be something we are 'missing' that makes the above argument about particle properties wrong.
Now, here is where people flip their proverbial shit: when the math is done out, it turns out that this is right. As far as the experimenter is concerned, the particles might as well be everywhere, every 'color', every spin, whatever, until he observes them. The universe is equally as clueless: the electrons of an atom really are everywhere at the same time. Why? Because the only tool any thing has to look at particles are other particles. Thus, until two interact, no one, no thing has any clue what the hell the particles are doing beforehand.
The proof ( I am a little tired, but I think this is the case) of this zany reality is that particles have too much energy: if you calculate a deterministic universe model of an electron, that is it is in one place right now, here, moving at this velocity, the energy you measure is larger than what you calculated. This is perplexing, until you calculate the energy the electron would have if you summed all the possible energies it could have weighted by the probability of that given state. Then you get the energy measured. This leads to the "quantum wave function," which describes the probability of each state of a given particle. "collapsing the wave function" means to measure the particle in question, as at that point the particle has an observed state that you know; the wave function only outputs that state with probability 1.
This allows weird shit to be possible. Since each quantum object can have all states at a given time before it is measured, 2 bits represented by a quantum object can together be the numbers 0,1,2, and 3 all at the same time, because as long as I don't measure them, they might as well be. BUT it is really the case that they are all three numbers at the same time, as far as the universe is concerned, so I can have them do multiple things, test multiple answers, all at once. Then I measure them and get the right answer...which if you follow the logic backwards sorta means that the 2 qubits held the answer the whole time, you just didn't know yet. But they didn't...and did at the same time.
Honestly put that way it is kinda like making a quantum processor is like hacking the universe; where normally trying everything at once is impossible, we do it anyway when the universe has its back turned, then it when it starts to pay attention we just take the result and declare that we knew that the whole time...because the qubits held the answer in the first place...but didn't.
Or more accurately: Now that it is now, we knew the answer as soon as we asked the question, but when it was then, that is, when we had the answer, we didn't. Until now, because now, we did.
Okay, I am just having fun those last couple of sentences, not really right. But fun.
Quantum entanglement basically "links" the probabilities of two particles together. On quantum scales, nothing has a known state until you measure it, so the two particles have all states at the same time, it just so happens their states "line up." When one is spinning clockwise, so is the other (roughly speaking, of course). The idea being you change one particle to 'up' and the other follows suit. The problem is, while unmeasured the two particles "line up," as soon as you measure one to see if the bits have changed, it screws up the entanglement. So you can alter the states of the particles faster than light, but the math keeps you from transmitting any information this way as you can count on the particles having the same state, just not when you want to know what state that is. If you could, then the universe would be fucking broken. Like, you know how in Dogma proving the big man (or woman
) wrong would 'unmake' everything in the blink of an eye? It would be like that. Existence would unravel.
Not to say that, like in Dogma, there may be loopholes...
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Topic: Yale Researchers Create First Quantum Processor (Read 20843 times)