3 ms·

Your argument in all honor, but it doesn't make sense, because I said that "it will be there soon enough for commercial purposes". Again, I didn't say that it's

by X4 13y ago

Your argument in all honor, but it doesn't make sense, because I said that "it will be there soon enough for commercial purposes". Again, I didn't say that it's commercially available today for you to sell to your customers. StackOverflow is not a good source, especially that thread, it is full of bad answers. I've read all of them. The first poster said: "Those quantum states may encode classical information." The poster of the question has obviously no clue about physics and nobody in there mentioned teleportation of quantum entangled states, which you should know, is instant. Here's a more detailed explanation, if you prefer that: If you have a particle (such as a photons, electrons, or molecule) and have it physically interact with another particle, and then separate them, the result is that they can then both be described as being in the same quantum mechanical state. Basically, they are now the same, in factors such as position, momentum, spin, polarization, etc. However, because we are dealing with quantum mechanics, the state of those particles remains undefined until measured (because it would then be forced to assume a specific state). Now, how does this relate to instant data teleportation, you say? That’s the interesting part. You see, quantum entanglement is a form of quantum superposition (which I talked about in the aforementioned post about some quantum mechanics). This means that each particle that you have can be in any state. (Remember: observing a particle will force it to become a specific state). However, when you observe one of the particles, it will become a certain state, while the other particle becomes the opposite state. The change is completely instantaneous, and the particles can be anywhere — you could have your second particle on the other side of the planet and it would assume an equal and opposite state of it’s entangled counterpart. Instant data transfer. Say you had a binary bit you wanted to transfer. First, you must entangle the bits. Then, put one of them on the other side of the globe. Observe one of them, forcing it to assume a certain state, and the other will instantly change. Like magic. Source: [1] Ask me about latency here… However, you drifted the discussion to QT. My initial post was originally trying to say that data can be transfered wirelessly faster than with a cable, or at least as fast. Latency cannot in such a system cannot be generalized, because it is dependant on the technology in the receiving side. If the receiving side uses optical fiber, you would need an architecture as described in [2]. --- [1] http://programmingantics.wordpress.com/2012/08/15/quantum-entanglement-instant-data-teleportatio/ http://programmingantics.wordpress.com/2012/08/15/quantum-en... [2] http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5229310 http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5...

Kell 13y ago
"If you have a particle (such as a photons, electrons, or molecule) and have it physically interact with another particle, and then separate them, the result is that they can then both be described as being in the same quantum mechanical state. Basically, they are now the same, in factors such as position, momentum, spin, polarization, etc. However, because we are dealing with quantum mechanics, the state of those particles remains undefined until measured (because it would then be forced to assume a specific state)." No they are NOT in the same quantum mechanical state at the moment of entanglement. They are, as you said later, undetermined until measurement (or better, until the collapse of the wavefunction). So they are not the same before, unless you accept the completely discredited theory of local hidden variables (cf. Bell's Theorem). They are connected, by the spooky action at a distance, and at the moment of measurement of one, the other will react accordingly. But before that measurement neither are in any state at all. But at least I've pinpointed the point where you got QT wrong : "Say you had a binary bit you wanted to transfer. First, you must entangle the bits. Then, put one of them on the other side of the globe. Observe one of them, forcing it to assume a certain state, and the other will instantly change. Like magic." The problem, see, is that, by definition of quantum mechanics, the collapse of the wavefunction is completely random. You can't force a photon to assume the state you want, it'll assume a random state. Then the other photon will indeed assume the symmetrical state. But that's still be the product of the randomness of the first measurement. In other words, causality has not been violated because no information is transmitted, only randomness. It's like having two connected dices separated by hundred of miles, when you roll a 1, the other rolls a 6, when you roll a 2 the other will roll a 5 etc. So you roll your dice, and you look at it. You got a 4 ! Great. Now you know that somewhere around in the world someone is looking at his own dice and seeing a 3. Did you transmit any kind of information ? No you knew beforehand that the guy would have a symmetrical result. And you can't tell him a message, because it's completely random. How would you say to your friend on the other side of the planet "Hello" ? You just got 5 fours in a row on the dice... Your friend know it. But that has no meaning at all. Now, of course, you can imagine local hidden variables, that could be read beforehand to influence the result. Or use another way of influencing the result of the wavefunction collapse, so that a message could be transmitted. But that's what I was speaking of when I said that you had first to reinvent the laws of physics. Cause the Bell's theorem and the No Communication Theorem forbid it in the actual understanding of science. Boy I would love to live in an universe where we can so easily violate causality. That would be FUN !

by X4 13y ago

Kell 13y ago

"If you have a particle (such as a photons, electrons, or molecule) and have it physically interact with another particle, and then separate them, the result is that they can then both be described as being in the same quantum mechanical state. Basically, they are now the same, in factors such as position, momentum, spin, polarization, etc. However, because we are dealing with quantum mechanics, the state of those particles remains undefined until measured (because it would then be forced to assume a specific state)." No they are NOT in the same quantum mechanical state at the moment of entanglement. They are, as you said later, undetermined until measurement (or better, until the collapse of the wavefunction). So they are not the same before, unless you accept the completely discredited theory of local hidden variables (cf. Bell's Theorem). They are connected, by the spooky action at a distance, and at the moment of measurement of one, the other will react accordingly. But before that measurement neither are in any state at all. But at least I've pinpointed the point where you got QT wrong : "Say you had a binary bit you wanted to transfer. First, you must entangle the bits. Then, put one of them on the other side of the globe. Observe one of them, forcing it to assume a certain state, and the other will instantly change. Like magic." The problem, see, is that, by definition of quantum mechanics, the collapse of the wavefunction is completely random. You can't force a photon to assume the state you want, it'll assume a random state. Then the other photon will indeed assume the symmetrical state. But that's still be the product of the randomness of the first measurement. In other words, causality has not been violated because no information is transmitted, only randomness. It's like having two connected dices separated by hundred of miles, when you roll a 1, the other rolls a 6, when you roll a 2 the other will roll a 5 etc. So you roll your dice, and you look at it. You got a 4 ! Great. Now you know that somewhere around in the world someone is looking at his own dice and seeing a 3. Did you transmit any kind of information ? No you knew beforehand that the guy would have a symmetrical result. And you can't tell him a message, because it's completely random. How would you say to your friend on the other side of the planet "Hello" ? You just got 5 fours in a row on the dice... Your friend know it. But that has no meaning at all. Now, of course, you can imagine local hidden variables, that could be read beforehand to influence the result. Or use another way of influencing the result of the wavefunction collapse, so that a message could be transmitted. But that's what I was speaking of when I said that you had first to reinvent the laws of physics. Cause the Bell's theorem and the No Communication Theorem forbid it in the actual understanding of science. Boy I would love to live in an universe where we can so easily violate causality. That would be FUN !