Scientists unveil the first-ever image of quantum entanglement

Scientists unveil image of quantum entanglement
Full-frame images recording the violation of a Bell inequality in four images. (A) The four coincidence counting images are presented, which correspond to images of the phase circle acquired with the four phase filters with different orientations, θ2 = {0° , 45° , 90° , 135°}, necessary to perform the Bell test. Scale bars, 1 mm (in the plane of the object). (B to E) The coincidence counts graphs as a function of the orientation angle θ1 of the phase step along the object are presented. As shown, these results are obtained by unfolding the ROIs represented as red rings and are extracted from the images presented in (A). The blue dots in the graphs are the coincidence counts per angular region within the ROIs, and the red curves correspond to the best fits of the experimental data by a cosine-squared function. (B) to (E) correspond to phase filter orientations θ2 of 0°, 45°, 90°, and 135°, respectively. Credit: Science Advances (2019). DOI: 10.1126/sciadv.aaw2563

For the first time ever, physicists have managed to take a photo of a strong form of quantum entanglement called Bell entanglement—capturing visual evidence of an elusive phenomenon which a baffled Albert Einstein once called 'spooky action at a distance'.

Two particles which interact with each other—like two photons passing through a beam splitter, for example—can sometimes remain connected, instantaneously sharing their physical states no matter how great the distance which separates them. This connection is known as , and it underpins the field of .

Einstein thought quantum mechanics was 'spooky' because of the instantaneousness of the apparent remote interaction between two entangled particles, which seemed incompatible with elements of his special theory of relativity.

Later, Sir John Bell formalised this concept of nonlocal interaction describing a strong form of entanglement exhibiting this spookiness. Today, while Bell entanglement is being harnessed in like and cryptography, it has never been captured in a single image.

In a paper published today 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.

They devised a system which fires a stream of entangled photons from a quantum source of light at 'non-conventional objects' – displayed on liquid-crystals materials which change the phase of the photons as they pass through.

They set up a super-sensitive camera capable of detecting single photons which would only take an image when it caught sight of both one and its entangled 'twin', creating a visible record of the entanglement of the photons.

Scientists unveil image of quantum entanglement
Imaging setup to perform a Bell inequality test in images. A BBO crystal pumped by an ultraviolet laser is used as a source of entangled photon pairs. The two photons are separated on a beam splitter (BS). An intensified camera triggered by a SPAD is used to acquire ghost images of a phase object placed on the path of the first photon and nonlocally filtered by four different spatial filters that can be displayed on an SLM (SLM 2) placed in the other arm. By being triggered by the SPAD, the camera acquires coincidence images that can be used to perform a Bell test. Credit: Science Advances (2019). DOI: 10.1126/sciadv.aaw2563

Dr. Paul-Antoine Moreau of the University of Glasgow's School of Physics and Astronomy is the paper's lead author. Dr. Moreau said: "The image we've managed to capture is an elegant demonstration of a fundamental property of nature, seen for the very first time in the form of an image.

"It's an exciting result which could be used to advance the emerging field of quantum computing and lead to new types of imaging."

The paper, titled 'Imaging Bell-type nonlocal behavior', is published in Science Advances.


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Researchers explore quantum entanglement

More information: Paul-Antoine Moreau et al. Imaging Bell-type nonlocal behavior, Science Advances (2019). DOI: 10.1126/sciadv.aaw2563
Journal information: Science Advances

Citation: Scientists unveil the first-ever image of quantum entanglement (2019, July 13) retrieved 21 October 2019 from https://phys.org/news/2019-07-scientists-unveil-first-ever-image-quantum.html
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Jul 13, 2019
ER=EPR

Jul 13, 2019
The paper is open access. See the link above at the end of the article.

Jul 13, 2019
The article is badly written. For one example,
Two particles which interact with each other—like two photons passing through a beam splitter, for example—can sometimes remain connected, instantaneously sharing their physical states no matter how great the distance which separates them.
No, it's not the beam splitter. You need an SPDC, a spontaneous parametric down converter. Photons don't interact with one another in a beam splitter; they interact with the beam splitter material. In the caption to the image of the experimental rig, this is called a "BBO crystal," a known SPDC.

Jul 13, 2019
It's a plasmoid!!!!! :)

Jul 13, 2019
So going by a couple of commenters, every entanglement is supposedly a wormhole (well hooray for Hollywood), and anything I read about entanglement created by a beam-splitter is supposedly nonsense, which presumably keeps all the supernatural cosmic dice tossing, and spooky action at a distance, to a tolerable minimum. Teleportation without this special crystal and maybe some special lights and sounds is obviously just a waste of time.

Jul 13, 2019
"have managed to take a photo of a strong form of quantum entanglement called Bell entanglement"

Again we have an article, evidentally written by the university's generic staff-writer, that mistakes instance for type: this not an image of a single entangement event. It's not [an] entanglement caught in the act. It is not a 'photo'. "photo", "photograph", and even "picture" appear nowhere in the paper. From the paper:

"MATERIALS AND METHODS
The four images shown in Fig. 3A and the single image shown in Fig. 2A were each obtained by acquiring 40,000 frames each of 1 s of exposure, during which time the camera intensifier was triggered for every heralding detection by the SPAD..."

This is old-fashioned signal-averaging.

Jul 13, 2019
"They set up a super-sensitive camera capable of detecting single photons which would only take an image when it caught sight of both one photon and its entangled 'twin', creating a visible record of the entanglement of the photons."

https://www.youtu...x1MUw2TU

Not sure how it's new, but it seems to have mostly spin-2 symmetry (helicity), which is maybe neat.

Jul 13, 2019
"They set up a super-sensitive camera capable of detecting single photons which would only take an image when it caught sight of both one photon and its entangled 'twin', creating a visible record of the entanglement of the photons."

https://www.youtu...x1MUw2TU

Not sure how it's new, but it seems to have spin-2 symmetry (helicity), which is maybe neat.
Whatever it is, the fact is that whatever we see in the image(s) is not an instance of a single biphoton interaction. Each instance registers at a single point at (x,y) in the detector, and constitutes a single pixel of thousands that build up an image showing the effect of the phase object's rotation.

Jul 13, 2019
OK, looking this over it's basically a rerun of Afshar. Except they get pretty images instead of ugly graphs. No major scientific advance here.

Jul 13, 2019
"a single pixel of thousands that build up an image"

Right, just like in the above article quote I gave there and just like in the video from IQOQI Vienna that precedes this article by many years. Got it. Anything else?

Jul 13, 2019
"a single pixel of thousands that build up an image"

Right, just like in the quote I gave there and just like in the video from ITTU Wein Vienna that precedes this article by many years. Got it.
I'm not critiquing the comment, just clarifying a salient issue missing from the quote. "which would only take an image ". This 'image' business is going around the media as though the researchers had taken a photo of a single entanglement item. Even the lead researcher is not helping the U of Glasgow staff writer with that phrase.

Jul 13, 2019
The problem I see here is that detecting an entangled particle destroys the entanglement, they are no longer entangled and superpose upon detection, they have a single state that requires no communication of any kind between the particles.

In essence, they have imaged a pair at the end of entanglement at best.

Jul 13, 2019
"I'm not critiquing the comment"

Fine.
As far as the setup goes maybe it's a "first" for them. Congratulations to them. Maybe every reader is missing something. Hopefully not. I just don't know.

Jul 13, 2019
"I'm not critiquing the comment"

Fine.
As far as the setup goes maybe it's a "first" for them. Congratulations to them. Maybe every reader is missing something. I just don't know.
Possibly. If I sound annoyed about something, it's about the persistent type-as-instance fallacy that so often reaches the public after it comes through both media and academic staff-authors' meat grinders about quantum experiments. That matter is not trivial; an  i n s t a n c e  of a quantum event is incredibly hard to probe in a given physical test setup when it envolves supporting or falsifying some key element of quantum theory.

Jul 13, 2019
The problem I see here is that detecting an entangled particle destroys the entanglement, they are no longer entangled and superpose upon detection, they have a single state that requires no communication of any kind between the particles.

In essence, they have imaged a pair at the end of entanglement at best.
They haven't even done that. They have averaged thousands of detections and called that averaging "an image" of... w h a t?

Jul 13, 2019
I seem to recall a simple experiment where a single photon hits a "beam-splitter" (polarizer, I suppose) and supposedly takes one of the two possible channels to a "beam-combiner" (another polarizer, I guess) where the only way the original photon can emerge basically unchanged by the splitter-combiner is if the supposedly unused one of the two channels is not blocked.

I suppose an "imaginary" (zero-energy) photon-impact-imprint signal taking the beam-splitter's "not used" exit effectively carries the beam-splitter's impact, allowing the subtractive imprint to be re-joined with the splitter-impacted photon in the beam-combiner. For two adjacent photons from a laser I guess the prepared states are "entangled" to some extent maybe.


Jul 13, 2019
I used polarizers as an example but it is the same thing with dual slits, I mean each photon picks one slit to conduct at least half its impact while the other slit carries the electromagnetic impact of the splitting on the photon, to be recombined in an interference pattern at the combiner screen. The slit-screen supposedly-unused-slit impact signal is, I think, imaginary (net-zero momentum) energy entangled with the photon, in effect.

Jul 13, 2019
"would only take an image when it caught sight of both one photon and its entangled 'twin'"

If two adjacent photons of a laser hit a splitter-combiner and they take opposite paths, then each path gets a splitter-affected photon along with the splitter-impact image of the opposite-path splitter-affected photon, you could still suppose each of the two channels carries a single one of two splitter-entangled photons.

Jul 13, 2019
Whether it's polarizers, slits or some other sort of light-screen, it's kind of analogous to a drum. I mean drums radiate both directions and all around, A lot of people overlook screen back-reactions and think upstream splitter events cannot possibly be influenced by downstream optics.

Jul 13, 2019
More fake science from phys.org. Quantum entanglement is snake oil.

Jul 13, 2019
So going by a couple of commenters, every entanglement is supposedly a wormhole (well hooray for Hollywood), and anything I read about entanglement created by a beam-splitter is supposedly nonsense, which presumably keeps all the supernatural cosmic dice tossing, and spooky action at a distance, to a tolerable blah
You're a spammer right? This is you:
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-You post a few legitimate posts under multiple Anonymxxxxxx socks to fool automated detection systems, and then flood with spam.

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Jul 13, 2019
I only use one name on this website. Otto's ghost must like wormholes a lot. I'm guessing copious amounts of alcohol are involved.

Jul 13, 2019
Entanglement is not snake oil but it does get horribly overhyped as having instantaneous information transmission wormhole-type capabilities. "ER = EPR" is Hollywood-friendly garbage.

Jul 13, 2019
TheGhostofOtto1923

Woops, voted you a thumbs down my mistake when I meant to give you a thumbs up for correctly pointing out the fact that Anonym is a no-good dishonest obnoxious spammer. Sorry about that.

Jul 13, 2019
Worm-holes are too much like double-vision, there has to be a connection there.

Too bad trolls run the ratings, but that's completely predictable.

Jul 13, 2019
pointing out the fact that Anonym is a no-good dishonest obnoxious spammer. Sorry about that
-thinks he's sooo clever.
Too bad trolls run the ratings, but that's completely predictable
Ok so explain why you use the odd Anonym****** handle, same as the dr takuta spammers, who also posted many seemingly legitimate posts.

Coincidence?

Physorg routinely bans scumbag spammers right away but not you. They probably can't 'see' you because you're getting upvotes etc. Amiright?

Jul 13, 2019
They try to impress people by dragging quasar light into their setups. Longest noise-only imaginary wormhole in the universe. Awesome.

Jul 13, 2019
Dr. Tookooka? Make sure you spell it right next time. It's more like Dr. Tookootootookakaka, okay?

Jul 13, 2019
Dr. Otto Spookenstein if you want to question and lose track of the convenient numbering system used here, and pretend to be confused to indulge some secret spite, possibly involving wormholes, then hey that is totally on you.

Jul 13, 2019
That's not an explanation. Why'd you choose that name? Simple question.

Jul 13, 2019
"Otto," my man, the website automatically generated the name for me as something like a default option, and I saw no need to change it. To reiterate here, it's the only name I use at this website. Also please note I'm not selling anything. Now, can we move on or am I taking you too much at face value here? I'm guessing B.

Jul 13, 2019
Well why didn't you just say so instead of insults? Not very neighborly.

Like I say, other anonyms are mixing seemingly valid postings with spam, and they are not getting banned. Spammers are universally annoying, no? Except to other spammers I suppose.

Jul 13, 2019
"why didn't you just say so instead of insults?"

You're saying "scumbag" is a term of endearment then. In your family, I suppose.

In that case why don't you just mind your own business instead of immediately dragging me into some stupid dr. Kootookookoo garbage. Be honest, it's the wormhole denigration and the double-vision comment, right? Dump the act, clown.

Jul 13, 2019
Hmmm I'm still not convinced. Scumbag spammers are everybody's business.

'Ban them all let god sort them out.'

Jul 14, 2019
The ER=EPR wormhole explanation could be really tight if you added a trampoline context to it. Just imagine an unused trampoline sitting flat on top of a big block of granite with a little hole drilled through the center of the block. You just grab a bit of the trampoline near the hole and then exploit the natural stretchy springiness of the trampoline's Fabric of Spacetime (TM) by yanking the fabrict all the way through the little hole.

Jul 15, 2019
Interesting photograph

Jul 15, 2019
OK, looking this over it's basically a rerun of Afshar. Except they get pretty images instead of ugly graphs. No major scientific advance here.

I saw the article on 'popular science' website and something about just made me feel 'cautious' so thought I would wait until I saw it here, hoping there would be comments. What I understand about entanglement is very little or 'elementary' so perhaps you could help me out here. From what I've read elsewhere the signal and idler photons can differ in energies as long as the two combined conserve. So my question is; what is necessary for these type of experiments, must both ent. photons be the same in all respects? Does the Barium crystal give better results over the Potassium one.
Ha, the only Afshar I was aware of, the people in Turkey, so I'll need to look up 'experiments involving that name.
Thanks in advance

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