I was under the impression that Socrates was permanently pissed.
Good to see he can handle quantum philosophy.
Japan has become the latest country to demonstrate quantum communication with a satellite, in this case a micro-satellite named SOCRATES. The National Institute of Information and Communication Technology (NICT) announced the quantum key distribution (QKD) test, which showed off the capabilities of its SOTA quantum …
> It's not really my area of expertise, but is this really "space-to-ground entanglement"?
No it's not, AFAICT. Reading the linked article, they seem to be (a) using the term quantum to mean that they can receive a signal so weak that only a single photon out of the burst sent for each data bit need be received in order to determine the value of that bit and (b) throwing in a reference to entanglement as science researcher click bait. What they are NOT doing is using entanglement to transmit / receive the signal.
but is this really "space-to-ground entanglement"?
It is, but only in the sense that entangled pairs of photons are being sent from space and received on the ground, so slightly misleading.
As the article says, if the photon pairs are intercepted in transit, they lose their quantum entanglement state - this can be detected by the receiver so any data received (i.e. encryption keys) will deemed to be insecure and discarded.
I was taking a graduate Quantum Mechanics course around 1970 when the EPR experiment demonstrating quantum entanglement was discussed.
One member of the class: "I don't believe it."
Instructor: "Didn't you follow the math?"
Student: "Oh yes, that was perfectly clear. I still don't believe it."
Instructor: "We could go to the lab and perform the experiment."
Student: "Oh, I believe that the experiment would come out that way."
Instructor: "So, what's the problem."
Student: "I still don't believe it."
You are not alone - you can understand it perfectly and still not believe it.
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