Originally posted by DaveStinger
reply to post by darkbake
So in quantum physics, two particles can be entangled and that means that when one of them is moved, the other one moves - it happens faster than the
speed of light, and can be used to communicate instantly at a distance.
This is a common mistake.
It can't used for instant communication because there always has to be a secondairy means of communication between the two points about the
manipulation, and this can only be done with a less than FTL speed.
That is conventional thinking, and what you're describing is a problem in Quantum mechanics termed 'Decoherence'.
Decoherence is conventionally thought of as the destruction (in communications) of the Quantum bit, or 'Qbit' by the action of not only measuring or
observing the Qbit, but indeed ANY action performed on it.
So the thinking is (was) that the decoherence of the Qbit, essentially destroying it's Quantum properties and reducing it into an ordinary bit, would
prevent Quantum communications using the phenomena of Quantum entanglement (action on one Quantum particle results in the reverse or opposite action
spontaneously occurring in it's paired Quantum particle) from effectively emerging, as a regular signal (laser, radio etc.) would need to be present
to piggy back the Quantum particle (say a photon).
This can be resolved, and resolved such that decoherence no longer is a problem.
The solution is a second set of Quantum 'interrogator' particles at both the sending and receiving ends of transmission.
Remember that ANY action by us on the Quantum particle or Qbit in the case of communications or computing, effectively destroys the Quantum effect?
Well..the obvious solution is to realise that while our observing, or reading, or interacting in any way destroys the Quantum effect...other Quantum
particles or Qbits DO NOT destroy the effect.
All that is required is to have the interrogating of the transit Qbit, the information being sent and recieved done by a locally generated set of
Quantum particles...yes the locally generated Qbits WILL experience decoherence, but that very decoherence will flip the particles and by that action
alone, we will be able to access the information in the transit particles, without destroying them, but recording which locally generated particles
tasked with interrogating the transit particles change value.
If a particle changes value, this can be read.
It's a little like a camera taking a photograph...the camera doesn't capture the subject...only a representation of the subject, a copy of where the
photons reflected from the subject were and in what state they were in, when the camera made a copy of them to produce a photo.
Reading the local Quantum 'copy' values (which will have reduced from Quantum state by our interaction with it) will allow us to extrapolate the
still Quantum information in the transit Quantum particles, which because they were interacted with by other Quantum particles, will not be affected
by decoherence because we would NOT be interacting with them, only other local Quantum particles would be, which wouldn't affect the transit ones.