[Widdekind]

From wikipedia, I understand the following re: QT:

• an entangled pair of particles is generated, sharing some property, e.g. spin, such that s₁* + s₂* = S₁₂
  
• the sender transmits the 'second' particle, to a remote receiver
  
• the sender entangles the 'first' particle, with an 'information' particle; and makes a measurement, of their combination, causing wave-function collapse, s₁*,s₂* --> s₁, s₂, s.t. i + s₁ = S_i1
  
• er go, the sender now knows, the quantum state, of the 'second' particle, at the remote receiver, s₂ = S₁₂ - s₁ = S₁₂ - (S_i1 - i) = i + (S₁₂-S_i1)
  
• the sender transmits the 'offset factor', S₁₂-S_i1, to the remote receiver
  
• the remote receiver 'subtracts off' that 'offset factor', from their 'second' particle, to recover the 'information', s₂ - (S₁₂-S_i1) = i

I understand, that QT can effect communications encryption. For, when transmitted, s₂ carries no meaningful information. And, if transmitted, the 'offset factor' S₁₂-S_i1 is meaningful information, but exclusively in application, to but one quantum 'particle', in all of the entire universe, i.e. s₂, presumably possessed by the intended remote receiver. Er go, potential eavesdroppers would only intercept "meaningless undifferentiated quantum randomness", or "meaningless-for-them quantum certainty". Is this simple picture accurate (if approximate) ?

[questionposter]

Widdekind, on 17 January 2012 - 08:08 AM, said:

From wikipedia, I understand the following re: QT:

• an entangled pair of particles is generated, sharing some property, e.g. spin, such that s₁* + s₂* = S₁₂
• the sender transmits the 'second' particle, to a remote receiver
• the sender entangles the 'first' particle, with an 'information' particle; and makes a measurement,

That's where it ends.

[Widdekind]

what are you saying, "that's where the information has been QT'd" ?

This post has been edited by Widdekind: 18 January 2012 - 08:08 AM

[questionposter]

Widdekind, on 18 January 2012 - 08:08 AM, said:

what are you saying, "that's where the information has been QT'd" ?

You can't measure an entangled system and continue to observe it's effects, unless your dealing with something like liquid helium.

[Widdekind]

'measurement' induces a 'wave-function collapse', "conforming" the collapsing wave-functions into certain states. The QT process exploits QE, to "conform" a wave-function, into a known state, without directly measuring-and-disturbing that state.