Scientific American Entanglement Movie

[Zafa Pi]

Scientific American created a short movie purporting to explain entanglement and the Bell experiment at:
http://www.scientificamerican.com/video/quantum-entanglement-the-movie-2012-01-30/

The part that interests me is near the end when explaining what is possible with entangled photons, which I believe is fatally flawed. I am wondering if the QM community here agrees.

 

[Doc Al]

I haven't watched the video, but the description states "In this dramatized film, Scientific American editors George Musser and John Matson try to fool a colleague into thinking their brains are quantum-entangled."

Are you sure it's meant to be serious? What claim are they making that you question?

 

[Zafa Pi]

I haven't watched the video, but the description states "In this dramatized film, Scientific American editors George Musser and John Matson try to fool a colleague into thinking their brains are quantum-entangled."

Are you sure it's meant to be serious? What claim are they making that you question?

It is meant to be serious. The claim starts at 7:20.

 

[Strilanc]

Here's a youtube link (the site you linked to has overlay spam):

Are you sure it's meant to be serious? What claim are they making that you question?

It's just a framing device for the video. They build up from "look we're doing the same thing!" to being forced (and failing) to violate Bell inequalities as a skeptical colleague keeps not believing them.

The part that interests me is near the end when explaining what is possible with entangled photons, which I believe is fatally flawed.

The worst mistake is they basically say quantum systems pass the CHSH test 100% of the time. That's wrong. The actual pass rate is at most 85-ish percent of the time. If they wanted 100% quantum success then they should have used a more complicated test, like the mermin-peres magic square game.

Also I don't like that they implied that entanglement was a permanent state of affairs, as if you could keep re-using entanglement to pass tests again and again. But... after fixing that CHSH-100% issue, I think the more pressing issue would have been improving the cinematography. The pacing and the acting leave a lot to be desired.

 

[Zafa Pi]

Here's a youtube link (the site you linked to has overlay spam):


It's just a framing device for the video. They build up from "look we're doing the same thing!" to being forced (and failing) to violate Bell inequalities as a skeptical colleague keeps not believing them.
The worst mistake is they basically say quantum systems pass the CHSH test 100% of the time. That's wrong. The actual pass rate is at most 85-ish percent of the time. If they wanted 100% quantum success then they should have used a more complicated test, like the mermin-peres magic square game.

Also I don't like that they implied that entanglement was a permanent state of affairs, as if you could keep re-using entanglement to pass tests again and again. But... after fixing that CHSH-100% issue, I think the more pressing issue would have been improving the cinematography. The pacing and the acting leave a lot to be desired.

Exactly, "the CHSH test 100% of the time" was my concern. It violates Tsirelson's inequality. To set it right for the video it becomes cumbersome because they would then need to show that without QM 75% is max. Thank you for validating.

What you call the "mermin-peres magic square game", which I've heard called by the more colorful "quantum pseudo-telepathy" might actually be easier to present correctly due to the lack of difficulties that arise from the 85% vs 75% issue. It is quite spectacular, and makes for a great math problem that no one (unless s/he knows of a QM solution) can solve.

Also the "re-using entanglement" is a bother, yet is easily fixed by continually using fresh pairs of entangled photons.

Work up a sophisticated video critique and send to the Newyorker. :-)