Scientists unveil the first-ever image of quantum entanglement

July 13, 2019 7:03 PM

For the first time ever, physicists have managed to take a photo of a strong form of quantum entanglement In a paper published today (July 13, 2019 ) in the journal Science Advances, a team of physicists from the University of Glasgow describe how they have made Einstein's spookiness visible in an image for the first time.
posted by 922257033c4a0f3cecdbd819a46d626999d1af4a (23 comments total)

I'm going to be the uninformed and confused public here and talk about what, to a layman, looks like the Elephant in the room.

"If the two particles are entangled, then performing an action on one has an immediate effect on the other and our paper shows how this effect can be demonstrated in an experiment with entangled photons."

If you want to send a message from point A to point B, you do something to one of the entangled particles at point A and a person immediately sees effect on the particle at point B. How is this not instantaneous communications between two distant points, violating relativity?
posted by eye of newt at 7:31 PM on July 13, 2019 [1 favorite]

OK, so now we can get started on unraveling the worst timeline?
posted by Abehammerb Lincoln at 7:48 PM on July 13, 2019 [5 favorites]

That's a question, isn't it?

Not sure we have the answers for that currently do we?
posted by Windopaene at 7:52 PM on July 13, 2019

The question about exploiting quantum entanglement to achieve faster-than-light communication was covered in this previous thread.

Short answer: that's not quite how it works. FTL communication is still impossible.
posted by escape from the potato planet at 8:14 PM on July 13, 2019 [6 favorites]

If you want to send a message from point A to point B, you do something to one of the entangled particles at point A and a person immediately sees effect on the particle at point B. How is this not instantaneous communications between two distant points, violating relativity?

The explanation given to me was that:

- if you have a red sock and a green sock,
- you put one on a spaceship without observing either,
- and you observe your sock to be red when the spaceship is past Pluto

you "instantaneously" know that the sock on the spaceship is green.

To a degree, this seems trivial. But you would be able to know if somebody had tampered with your space-sock and sent the green one into space instead when you had intended to send the red one.
posted by solarion at 8:21 PM on July 13, 2019 [2 favorites]

Yes, but in this experiment they aren't just observing that the sock is red. Read the quote I used above. They 'performed an action' on the red sock, then the person in the spaceship saw a similar effect on the green sock.
posted by eye of newt at 8:26 PM on July 13, 2019 [1 favorite]

Entanglement is a correlation, not actual information in the strong sense of the word. To use the typical example, say you entangle two photons such that one is left hand polarized and the other is right hand polarized. You then ship one off to Pluto. Once it gets there, you can measure the polarization of the one still on Earth, find it is left handed and know that the one on Pluto is right handed.

By measuring them, the entanglement is destroyed, so if you arrange things such that you can communicate information you necessarily destroy the entanglement.
posted by wierdo at 9:09 PM on July 13, 2019 [1 favorite]

I read several articles about this and am still confused, is the picture of the actual photons or of a surface that the photons are striking, like you would see in an interference pattern (slit experiment)? is the indication that they are entangled that the "bow" is pointing in exactly opposite directions?
posted by Rufous-headed Towhee heehee at 9:20 PM on July 13, 2019

I'm looking at Wikipedia and it looks like the correlation explanation is really a partial explanation that competing theories all generally agree on.

So with the separated socks, the paradox is, How could the two socks possibly know each other's state given that nobody - not even the socks themselves - knew their own colors until somebody measured one?
posted by polymodus at 9:53 PM on July 13, 2019

The obvious answer is that reality has global hidden variables. The Bell Inequality is often described loosely as ruling out hidden variables generally, but in fact only rules out local hidden variables. That is to say, the hidden variable cannot be a property of the particle itself, it must be a global property.

Another possibility, of course, is that space doesn't actually work like we think it does. Perhaps the entangled particles remain, in some sense, spatially nearer to each other than we think they are.

Since we don't have the answers yet, any explanation is at best speculative.
posted by wierdo at 10:05 PM on July 13, 2019 [2 favorites]

I now realize that the quote I gave was from something earlier (in the 'Explore Further' link). The short description in this article sounds more like what solarion describes--they are just monitoring the entanglement. So I guess there's no elephant in the room yet, at least according to my limited layman's understanding.
posted by eye of newt at 10:19 PM on July 13, 2019

Yeahbut just the other day, the Science Channel told me that the Chinese claimed to have "teleported" a signal to a satellite, using quantum entanglement. The Science Channel claimed their being able to do that was some kind of a security threat. I was too confused to be scared, but it was the Science Channel, so it must be true.
posted by Kirth Gerson at 2:34 AM on July 14, 2019

Warning: there seems to be a naughty ad on the linked page. Tries to hijack my browser with lots of repeated “Congratulations! Your chance to win a special reward” dialogs + redirects etc. every time I click it, so I haven’t had a chance to read the article yet.
posted by faceplantingcheetah at 3:19 AM on July 14, 2019 [1 favorite]

faceplantingcheetah, there's rarely such a thing as a specific ad being "on" a specific page these days. (And there hasn't been for quite some time.) Web ads generally aren't purchased for specific placements on specific sites any more.

Rather, advertisers tell the ad network "I want my ad to be seen by people who match xyz interests / demographics / behavior". Then, whenever you view a web page which contains an ad slot, the advertising platform looks at its profile of you, finds an ad that it thinks fits you, and loads that ad into the slot. This all happens instantaneously and on the fly.

So everyone sees different ads, even if they're looking at the same page.
posted by escape from the potato planet at 4:19 AM on July 14, 2019

So everyone sees different ads, even if they're looking at the same page.

e.g.: I'm on an old Google Nexus 5 and man, the ads keep telling me how easily I can upgrade to a Google Pixel 3a
posted by mikelieman at 4:43 AM on July 14, 2019

Ah, thanks all. Not sure what my chosen ads say about me in that case. Nothing good, I’m sure.
posted by faceplantingcheetah at 5:02 AM on July 14, 2019 [1 favorite]

I think the elephant in the room is that even though we can't see the ads themselves until they appear, and yet knowing the ads are connected to the content, and anything that happens to the content affects the ads instantaneously, we can safely surmise that:

clicking on science articles has created the porn industry.

Which puts a rather interesting spin on exactly WHAT the "spooky action" at a distance might be and what it means for the future knowing we all like looking at it.
posted by Lipstick Thespian at 5:22 AM on July 14, 2019 [5 favorites]

So everyone sees different ads, even if they're looking at the same page.

Schrödinger's website.
posted by Thorzdad at 5:23 AM on July 14, 2019 [2 favorites]

Note: phys.org is a content farm which uncritically reprints press releases. But they do at least link to the actual paper.
posted by fantabulous timewaster at 5:27 AM on July 14, 2019 [1 favorite]

I figure that back at the beginning when all that is was one before form emerged all arrow of time like... The instantaneous boils down to a form of time travel. It goes back to the beginning when the universe was just a spot, steps to the left and goes forward to now and presto 15 billion light years away in an instant. If you can't break the speed of light, you just need to go back to when you could get everywhere that exists at the same instant that everything that is once was and then back to the now.
posted by zengargoyle at 8:47 AM on July 14, 2019 [1 favorite]

There are enough acronyms and abbreviations on the diagram that I can’t tell where the beam comes from and goes to and where the measurement is taking place.
posted by freecellwizard at 8:58 AM on July 14, 2019

>That's ironic, because when I go there, I receive a scoldbanner across the top of the page which says "It appears that you are currently using Ad Blocking software. What are the consequences?" <

I don't even get that... Thanks PiHole! (https://pi-hole.net/)
posted by twidget at 5:07 PM on July 14, 2019

So with the separated socks, the paradox is, How could the two socks possibly know each other's state given that nobody - not even the socks themselves - knew their own colors until somebody measured one?

Copenhagen: It's nonsense-talk that the socks had color prior to measurement. Sure, measuring one determines the other, just not in, you know, a causal way. It's just how the math works out. Stop asking so many questions and do the math.

Many Worlds: Sure, your sock was red all along in this universe, but it was green in the one next door. Opening the box just let you know which one you were in.

DeBroglie-Bohm: The socks are magically connected. Get over it. But you'll always end up fat-fingering opening the box so you'll never be able to impose redness.

Transactional: When you open the box there is an instantaneous information exchange but not because anything was traveling faster than light -- don't be ridiculous. It's just that that was when the waves the socks were sending backward and forward in time intersected.

That's been the vexing state of physics for nearly a century. We have a pile of interpretations of quantum wossname and they have two things in common:

1) they fit the truly massive amounts of experimental results
2) they do great violence to at least one thing that seems to be fundamental to a universe that makes any sense at all
posted by Zed at 4:10 PM on July 15, 2019 [4 favorites]