If you change one of the particles it just breaks the entanglement. If you measure one, then you instantly know the state the other will have when measured, but the result of your measurement - and therefore the other one also - is random. The only way to correlate the two measurements of the two particles is to send the results (at C or slower) to the same place and compare them. Otherwise each just looks like a random result.
Could you to the sub-C measurement test enough times to show that it just empirically works, and then use it on that basis? Or are you saying that the sub-C measurement would prove that it doesn’t work (and it produces random noise)?
I read it. Doesn’t mention FTL, because that’s not a possibility for actually transmitting info.
Edit: I think the way these quantum encryption systems work is that basically the photons (and I assume it’s polarization being measured) become the encryption key to a message that is sent conventionally.
Like the sender generates a bunch of entangled photons, sends the paired ones to the recipient, measures their photons and uses the results to encrypt the message, the receiver measures theirs and gets the same results, the sender sends the encrypted message over email or whatever, and the recipient has the same key because of entanglement.
Meanwhile an eavesdropper measuring the photons would mess them up for the recipient so the message wouldn’t decrypt.
If you change one of the particles it just breaks the entanglement. If you measure one, then you instantly know the state the other will have when measured, but the result of your measurement - and therefore the other one also - is random. The only way to correlate the two measurements of the two particles is to send the results (at C or slower) to the same place and compare them. Otherwise each just looks like a random result.
(I know nothing about this)
Could you to the sub-C measurement test enough times to show that it just empirically works, and then use it on that basis? Or are you saying that the sub-C measurement would prove that it doesn’t work (and it produces random noise)?
I’m not sure what you mean by ‘use it on that basis’. Yes, entanglement has been proven to work, but it can’t be used to communicate FTL.
Read the link posted. They already did it. In 2007. At a distance of 144km.
I read it. Doesn’t mention FTL, because that’s not a possibility for actually transmitting info.
Edit: I think the way these quantum encryption systems work is that basically the photons (and I assume it’s polarization being measured) become the encryption key to a message that is sent conventionally.
Like the sender generates a bunch of entangled photons, sends the paired ones to the recipient, measures their photons and uses the results to encrypt the message, the receiver measures theirs and gets the same results, the sender sends the encrypted message over email or whatever, and the recipient has the same key because of entanglement.
Meanwhile an eavesdropper measuring the photons would mess them up for the recipient so the message wouldn’t decrypt.