Real Science Radio: One Way Speed of Light Measurement Proposal

[JudgeRightly]

You can measure the quantum state of an entangled particle, which then instantly determines the quantum state of the particle it's entangle with, regardless of how far away it is, but as soon as you make that measurement, the entanglement goes away and, since there's no way for you to know the quantum state of either particle until you measure it, there's no way to use the system to send information because you can't even tell if someone has already measured the quantum state of the other particle until you measure it on your particle. Did you collapse the entanglement by measuring it or had it already been collapsed by the person you're trying to send a message too? You can't tell.

Exactly.

 

[Clete]

Exactly.

That's the way it's always been explained to me anyway.

It has consistently made me wonder how do they know that it was ever entangled in the first place.

 

[JudgeRightly]

That's the way it's always been explained to me anyway.

It has consistently made me wonder how do they know that it was ever entangled in the first place.

Observing two electrons being made simultaneously? Good question though...