Quantum Entanglement

 

 

Got some pretty good emails back from that opening statement yesterday.

 

It’s not like I totally understand what’s going on, but I’m fascinated by the concept that two subatomic particles can get inexorably bound (entangled).  When there are multiple possible states for two entangled particles, if you determine the condition of one, you know with certainty the condition of the other.  They’re probably not in the same condition, they’re probably opposite.  If we’re looking at entangled photons, they can have two different states, State A and State B.  (Left spin, right spin.)  Once these two particles are entangled, they will always be in opposite states.  If we change the state of one of these particles, the other will instantly change too.  They could be side by side or far away from each other, but the change will be instant, and instantly is even faster than the speed of light, which is not supposed to be possible.  Einstein called it “Spooky action at a distance.”

 

Action at a distance itself is not all that big a deal.  A magnet pulling iron filings across a sheet of paper without actually touching them is action at a distance.  Gravitational force between massive objects, like stars, planets, and galaxies.  That counts.  But these actions are explained by known classical physics magnetic and gravitation forces.  Quantum entanglement of subatomic particles is different.  With no known other force acting on it, you can instantly change the condition of a single particle by changing the condition of its entangled partner, wherever it is, whether they are right next to each other or on opposite sides of the Universe!