What is quantum entanglement?

[@LendallPitts]

The most recent demonstration that Einstein was wrong and that "spooky action at a distance" does indeed take place was by Alain Aspect in 2015. Alain is a great favorite of mine -- and quite amusing. He's on KZbin.

[@frun]

Entanglement is a time period until, suddenly, you only find one sock 🧦 and have to use one of a different color.

[@that_one_momo_guy]

Hi there! I love that you're doing outreach! The format of short videos explaining interesting phenomena is super handy for a quick "nugget of science." That said, I have some constructive criticism. The presentation in the video seems to make it more rather than less confusing. You can measure different properties of classical objects too: the shoes could've been one worn out and one not. This would give a strong correlation among two axes (and one could similarly continue making up examples to get correlation among as many axes as one wants). This seems to perpetuate the "mystical" way of explaining quantum phenomena to non-specialists: The only difference between the classical and quantum examples, as presented, is that the latter includes technical words ("spin", "quantum") that the non-specialist doesn't know exactly. So the feeling left by it is "the difference between the two is hidden in these quirky words which you won't understand", which defeats the purpose of doing outreach in the first place. Now, I don't mean that this was the intended outcome at all, but it seems to be the outcome regardless.

[@that_one_momo_guy]

One possibility to improve it is to explain it in terms of the typical Bell game with the referee and the two parties that can't communicate. It's as artificial as taking a lonely shoe to mars, and pin-points what the weird thing actually is. (I.e.: Rather than just mentioning the correlation game in the passing, make *that* the focus of the explanation.)

[@johnmatthewdonohue9866]

Hi Felipe! Thanks for the feedback! I 100% agree that the Bell-CHSH game scenario is the best way to learn about entanglement, and usually the intro point we use for public lectures. We hope to put out longer partner videos to these soon that get into a few more relevant details (incompatible measurements, for example) that were glossed over in the 3 minute version.

[@hosseinmashhadimoslem]

Nice, Thanks

[@ruttles]

Guys was he incorrect when he said entanglement CAN''T occur faster than the speed of light?

[@QuantumIQC]

Entanglement indeed cannot be used to communicate information faster than the speed of light. However, if we wanted to mimic the effects of entanglement, as shown in the experiments of researchers like Alain Aspect, we would need some kind of device that communicates faster than the speed of light. It's an important but subtle point: any kind of hidden-variable model that could explain or "fake" entanglement requires faster-than-light communication, but entanglement itself does not allow us to send messages faster than the speed of light.

[@schmetterling4477]

Entanglement is the absence of symmetry breaking mechanisms. Does "absence" travel faster than light? No. It's already NOT there. It's NOT there ALL the time. ;-)