Quantum Entanglement (split from electron spin)

[MirceaKitsune]

BTW: I heard a few months ago that scientists were able to use quantum entanglement to transport information between two crystals. Is this confirmed, and does it disprove the theory that entanglement can't be used to replace the existing internet infrastructure?

[swansont]

BTW: I heard a few months ago that scientists were able to use quantum entanglement to transport information between two crystals. Is this confirmed, and does it disprove the theory that entanglement can't be used to replace the existing internet infrastructure?

 

I'm not sure what "existing theory" you're referring to. People have been doing information transfer using entanglement (quantum teleportation) for several years now, and it's a candidate for more secure data transfer if it can be made efficient enough — it's still very early in the game, and the systems that test it aren't particularly robust.

 

You can use it for information transfer. The thing that it can't do is transfer information faster than light. That's the objection.

[sunshaker]

I recently watched a programme on D wave quantum computers which i found interesting.

 

https://www.youtube.com/watch?feature=player_embedded&v=DyhcFk8MnoE

 

Google nasa and a few others have already ordered systems.

http://www.ibtimes.co.uk/d-wave-raises-15m-advance-revolutionary-quantum-computer-development-1485858

[Enthalpy]

Acting on one particle will leave the other unchanged. Entanglement is used in secure datacomms, but as a way to detect if the channel has been tampered.

[MirceaKitsune]

 

I'm not sure what "existing theory" you're referring to. People have been doing information transfer using entanglement (quantum teleportation) for several years now, and it's a candidate for more secure data transfer if it can be made efficient enough — it's still very early in the game, and the systems that test it aren't particularly robust.

 

You can use it for information transfer. The thing that it can't do is transfer information faster than light. That's the objection.

 

I see. I remember people saying that entanglement can't be used to transfer information, because it only works when both ends compare the readings they got. So even if you can send information through entanglement, you separately have to send each end the information of what to expect from the other end... or something like that. Am I correct?

[imatfaal]

 

I see. I remember people saying that entanglement can't be used to transfer information, because it only works when both ends compare the readings they got. So even if you can send information through entanglement, you separately have to send each end the information of what to expect from the other end... or something like that. Am I correct?

 

You send a packet of information classically - combine this with the measurements you make of the entangled particles you can gather more information than the classical alone.

 

You can set up encryptions such that the classical alone is worthless - and if a middle man measures the particles to gain the "quantum" information then you will know about it because the entanglement will be broken and thus the recipient will know that the conduit of information has been breached. Additionally measuring the particles gets you no information unless you have the classical information as well.

[swansont]

 

I see. I remember people saying that entanglement can't be used to transfer information, because it only works when both ends compare the readings they got. So even if you can send information through entanglement, you separately have to send each end the information of what to expect from the other end... or something like that. Am I correct?

 

The classical information you have to send is how you made the measurement, e.g. what angle the polarizer set has for photon, or the spin axis for spin states. Without that, the deciphered information makes no sense. Because that's classically sent, the transfer is limited to c, which makes it useless for superluminal information transfer.