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Baby Steps Toward Quantum Computers
Mz6 writes "In a step toward making ultra-powerful computers, scientists have transferred physical characteristics between atoms by using a phenomenon called entanglement, which Einstein derided as 'spooky action at a distance' before experiments showed it was real. Such 'quantum teleportation' of characteristics had been demonstrated before between beams of light. Teleportation between atoms could someday lie at the heart of powerful quantum computers, which are probably at least a decade away from development. Researchers using lab techniques can create a weird relationship between pairs of tiny particles. After that, the fate of one particle instantly affects the other; if one particle is made to take on a certain set of properties, the other immediately takes on identical or opposite properties, no matter how far away it is and without any apparent physical connection to the first particle." Reader starannihilator adds: "Physics Web provides a good graphic summary of the phenomenon, as well as a good technical article."
...but not quite teleportation (at least as most people understand it).
Allah is the answer!
All I saw was the dame standing there in the glare of the headlights waving her arms like a huge puppet and the code I spit out filled the server and my own buffer.
I wrenched the wheel over, felt the backend start to slide, brought it out with a splash of bandwidth and almost ran up the side of a cliff as the car fishtailed. The brakes bit in, gouging a furrow in the uptime, then jumped to the pavement and held.
Somehow I had managed a sweeping curve around the babe. For a few nanoseconds she had been living on stolen time because instead of getting out of the way she had tried to stay in the stream of the headers. I sat there and let myself stabilize. The butt that had fallen out of my mouth had burned a hole in the leg of my pants and I flipped it out the port. The stink of burned silicon and brake lining hung in the air like smoke and I was thinking of every damn thing I ever wanted to say to a hairbrained MCSE so I could have it ready when I got my hands on her (?).
That was as far as I got.
In Soviet Russia, Chuck Norris will still kick your ass.
I like physics a lot. I have read a lot about string theory. I don't understand all of the mathemtics behind it, but PBS shows have helped me understand the basic nature of it. For a layman, I'd say I have a decent grasp of it.
But this quantum enanglement... It is explained so poorly, I do not understand how it works exactly or it's usefulness!
Here are some questions that have been bugging me:
1. If two particles are entangled, and you measure one... the other one instantly changes it's state. Once you have done this, can you measure either one of them AGAIN and produce another state change in both? Can you keep doing this without re-entangling them?
2. If the answer to 1 is yes, then has anyone found a way to DE-ENTANGLE the particles?
3. What happens if you take a particle that has been entangled with another particle, and try to entangle it with a third? Is this first entangement broken, or do you now have three entangled particles?
4. This is what's really been bugging me...
Let's say you entangle particle A and particle B.
If you cannot measure it without changing it's state, then how do you know that particle B's state changes when you change particle A's state?
In other words...
If have have two boxes... A and B, which have lids on them which are shut, and if I look in box A, and either a rubber duck, or a pineapple appears, how do I know that the contents of box B have changed? I cannot open box B to look at the contents beforehand to know when they change, because that would set the state of box A.
Furthermore...
If I cannot look in box B until after I have looked in box A, then how do I know that box B's contents have changed at all?
How do I know that when my assistant "entangled" box A and box B, that he didn't just go and place a pineapple in both? Since I cannot look in box B beforehand, and I cannot know whether box A does or does not contain a pinapple before I look in it, I have no way of knowing that box A, rather than containing a 50/50 probability of having a pinapple or a duck, does not, in fact just contain a pineapple, and only a pineapple, and box B, which I spent great amounts of money to ship to taiwan, did not in fact always ALSO have a pineapple inside it, because I could not look in it to see if there was a 50/50 state contained inside.
I just do not understand how quantum mechanics could come to the conclusions they have based on what these articles have said about it. It makes no sense. As far as I can tell, if I handed you two boxes and told you that they are entangled, but that if you look in either, it will make the state of both the same, how can you dtermine that that I have not just placed a pineapple in both, and tricked you into thinking you have somehow altered the state of one by looking in the other?