Quantum Entanglement Explained
Einstein called it "spooky action at a distance". He was wrong. The key to understanding entanglement is simple.. there is no
distance.
Sometimes building a model can help understand a phenomenon. So suppose you have two elementary particles that arose from the same quantum process. So they are a unified quantum system.
Let's denote that by placing a sphere around them. A bubble if you like. So the system is totally isolated from its environment.
Now postulate that inside the bubble, distance (as we define it) simply does not exist.
For example: suppose one particle moves 100 miles away and the bubble does not burst, so this is still a single quantum system and the 100 miles means nothing. The two particles are still a single unified system. That's entanglement.
But if the bubble bursts (by interaction with the environment, and that includes any measurement on the system) this thing is no longer a unified quantum system but simply two unrelated particles. And our usual definition of distance suddenly applies.
Here's a specific example:
Let's produce 2 photons by collideing an electron and a positron electron+positron-->2 photons. The electron and positron first form a bound state. Then this state decays into 2 photons. So the photons are entangled.
The photons travel at speed c in opposite directions, so they are soon separated by a vast distance, but still entangled (provided their bubble does not burst).
Now after many miles I measure the spin of one of the photons, and you measure the spin of the other. Once I get my answer I know your answer without you telling me.
That's entanglement.
It's not mysterious and certainly not "spooky" as Einstein said.
Tech Notes:
Note that we can never know what's going on inside the bubble. Never ever. It's a catch 22. To know what's going on we would need to make a measurement. But making a measurement bursts the bubble.
Entanglement teaches us an important lesson. At the quantum level distance is not what we think it is.
Disclaimer: This is not intended as professional advice. It's for informational purposes only.
Content written and posted by Ken Abbott abbottsystems@gmail.com
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