How to teleport quantum information over 100 km of Fiber
Creating the Quantum States
The NIST experiment adds quantum information to a photon in its position in a very small slice of time. The photon can take a short path, 50/50 chance… So it can be either “early” or “late” in the time bin. If we don’t know which, then it’s both a quantum “superposition” in time. If the photon is in a superposition of two states, they can be “in phase” – the peaks of their waves lining up with each other… or “out of phase“, with their waves canceling each other out.
How to Teleport Quantum Information
- Generate a photon in a superposition of possible states.
- A special crystal splits it into two identical photons, a helper photon, and an output photon. They are “entangled” – the state of one is duplicated in the state of the order.
- Generate an input photon in the state to be teleported. We pick its state: early, late or a superposition of both.
- The input photon and the helper photon meet at a beam-splitter. Each has a 50/50 chance of going straight through or reflecting off at an angle.
- A detector clicks when a photon arrives. When one detector clicks early and the other clicks late, this means the helper and input photons are in opposite stets: Early vs. Late or In-phase vs. out-of-phase superposition. Because of the photons’ random paths, this happens at best only 25% of the time. The other 75% are discarded.
- Because the output photon is entangled with the helper photon, we know it is in the same state – which is also (from step 5) the opposite state of the input photon. Detectors 3 and 4 measure the state of output photons to confirm.
This the step by step breakdown of how to teleport quantum information. If you enjoyed this article feel free to check out StarkFeed’s Science section. More articles like this: “How does the large hadron collider work?”