“Entanglement is the only way you could do this from an earth station to a satellite”
So, how did they get the entangled electron to the satellite? Did they entangle it before the launch and sent it up with the satellite? And how is that single electron stored and kept track of on both earth and the satellite?
And can many electrons be entangled to the same electron and among each other?
Also I don’t get how a photon “captures” the quantum state of an electron, since they’re such different “particles”.
Just trying to understand...
Yes, they’d surely have to entangle the electrons before launch and separate onto two different wafers. It’s not really as hard as it sounds. When you pull apart your clothes from the dryer and there’s static electricity, there’s millions of electron pairs that are entangled for a brief moment. Isolating a single entangled electron pair is being done in labs all over the place nowadays.
When you get to multiple electrons in an entangled “system”, that’s really complicated and organizing into something useful is hard to do, though it’s being done. Not to change the subject, but that’s what a quantum computer is. That’s a whole ‘nother topic.
As for the photon, it is simply electromagnetic energy produced by an electron going from a high energy shell around a nucleus to a lower energy shell. The angular momentum of the electron is captured in the photon generated when that happens. I can’t really say why the photon does this, but when it strikes another electron and transfers that energy to it, the angular momentum of the original electron is captured in the change observed on the target electron. I don’t know if the physicists understand how this happens; it may just be a phenomena they’ve observed.