back to article Literally rings our bell: Scottish eggheads snap quantum entanglement for the first time

Physicists at the University of Glasgow, Scotland, have produced the first-ever image of a strong form of quantum entanglement, known as Bell entanglement. To achieve this, they devised a system which fires a stream of entangled photons from a quantum source of light at "non-conventional objects" – which change the phase of …

        1. steelpillow Silver badge

          Re: The filtering is done BEFORE the Bells test

          You are missing the fact that Bell's theorem describes a difference between the filter output based on your scenario and the filter output based on nonlocal entanglement. Guess which model matches the actual laboratory results.

          Or, are you just pointing out the definition of an observation as an interaction of the observer with the observed, under the impression that this is something that the average quantum physicist has missed?

          Sorry buddy, I am signing off now before this gets even more painful.

        2. Yes Me Silver badge
          Headmaster

          Re: The filtering is done BEFORE the Bells test

          "NOT a magic force over an extra dimension propagating across space and time."

          That's a wonderful strawman to attack, but sadly for your somewhat tangled argument, it isn't in any way shape or form anything that Bell proposed.

          I'm possibly the only commentard here who actually met John Bell, and even sat in on a meal with him and Roger Penrose. Not that this, and a physics degree, qualify me to have an opinion. The point is that Bell proved a consequence of quantum mechanics that could be tested experimentally, which experiment showed that entanglement is an actual property of the universe we live in.

          There's no suggestion of a magic force. And nobody yet claims that string theory, which does posit extra dimensions that we can't perceive, is anything more than theory - unlike the Alain Aspect experiment that was the first test of Bell's theorem, there isn't (as far as I know) a proposed experiment to test even one of the many variants of string theory.

          I think I can safely say that nobody understands quantum mechanics.” [Richard Feynman] But that doesn't make it false, because experiments tell us it's true, including entanglement.

    1. Mike 125

      Re: How entanglement really works, how to prove it

      And here we clearly demonstrate entanglement- between YouTube and the Reg.

    2. Anonymous Coward
      Headmaster

      Re: A different option? You cannot break Bell theorem/observations!

      AFAIK one of the only possible alternatives is "throwing locality out the window". We generally cannot do that, because it breaks other math.

      However, if Quantum Loop Gravity ever gets a testable proof/applicable example, then we may find that the dimensionality "shape" of space/time is different than we first expected.

      So for example, it may be possible for the "interaction" to be passed through quantum scale sized worm holes, or similar mechanics.

      So we only have 3 options to the observed Bell inequalities.

      1) It's an unset measurement, and only given a result when the interaction happens, and one particle changes the possible interactions of any/all others, especially it's quantum clone (see no cloning theorem and many other limiting factors).

      2) We throw locality theory out the window. While it may not be possible to do so, I would guess the true result lies somewhere between quantum measurements and some new laws/observations on limitations of locality. I would think we may find out not all the universes particles/fields/waves are "local" as we first assumed.

      3) We throw causality out the window. Well, this is the only one totally not a real option... though it seems sadly some people do apply this to their thinking!!!

      1. Anonymous Coward
        Anonymous Coward

        Re: A different option? You cannot break Bell theorem/observations!

        "So we only have 3 options to the observed Bell inequalities."

        Four, The scientist pre-filters the results, the worm hole is the scientist making the connection between the two photons by filtering for some matching property.

        Those various types of motion are interlinked. (They are afterall properties of motion).

        Selecting the interlinked property from a limited set of possibilities selects the remaining possibilities.

        You then shove it in a Bells test and ignore the obvious.

        1. Anonymous Coward
          Anonymous Coward

          Re: A different option? You cannot break Bell theorem/observations!

          "Four, The scientist pre-filters the results, the worm hole is the scientist making the connection between the two photons by filtering for some matching property."

          That is the same as 2. It is literally the same. A scientist does not invent "temperature" an object has a property, and another object can measure it (even if temperature is a less accurately defined one ;) ).

          Even with no scientists in existence, light would still get polarized by materials and follow Bells (observed) inequalities.

      2. James Loughner

        Re: A different option? You cannot break Bell theorem/observations!

        Problem of loop gravity is the researchers keep trying to make the extra dimensions small because as we all know we only "see" 3 (well 4 if you throw in time) But the reason we only see 3 is that ever last thing we see feel observe is through electromagnet interaction and EM is 4 dimensional. So we can only experience , and thus know about, 3 spacial and one time dimensions.

        We are completely electromagnet entities. Just a bunch of extremely complesx EM fields. Think about it.

        1. Anonymous Coward
          Anonymous Coward

          Re: A different option? You cannot break Bell theorem/observations!

          Oh. I agree. They are only making a start. And will probably have to modify it.

          I would expect that it will change the same way Genreal Relativity did. We don't "observe" the bending of spacetime in everday observations (the closest you can get with the eyes is probably gravitational lensing of sunlight/stars or similar).

          So I would expect loop gravity to not be small dimensions but a new way to map the existing ones. Like for example an emergent "spacetime" from Quantum (particle/wave) interactions. That space and time are fundamentally a simpler system that builds up to our observations (as we discovered atoms build up into materials).

      3. steelpillow Silver badge
        Boffin

        Re: A different option? You cannot break Bell theorem/observations!

        3) dumping causality out the window is just an example of 2) dumping locality, but in time not in space. Since the whole thing happens in relativistic Minkowski spacetime, the distinction between space and time is not easily maintainable at a fundamental level. The most mathematically elegant approach is to assume nonlocality in both, which has the side effect of dumping causality to much the same limited extent that Relativity also dumps simultaneity. This has no ill effect on quantum theory or on Relativity theory, since neither has an inalienable forward direction in time. Only thermodynamics struggles with the reversal of causality, but then thermodynamics is still pretty much based on a Newtonian universe where Bell's theorem rules out quantum mechanics instead of ruling it in. Overall, just as simultaneity holds in all cases that actually affect any experimental outcome, so too is causality likely to.

        1. Anonymous Coward
          Anonymous Coward

          Re: A different option? You cannot break Bell theorem/observations!

          As far as I can understand I could theorize a spacetime that can have an emergent locality from a system that does not have it... but I don't know any good Quantum Mechanics Field Theorists to ask/discuss it with. Lol. XD

          PS progress has been made in non disiter space analysis so hopefully we will find some answers.

        2. Anonymous Coward
          Anonymous Coward

          Re: A different option? You cannot break Bell theorem/observations!

          PS, IIRC you don't have to dump causality out the window. As one example of a possible solution (that still needs some work), is setting up non traversable (you can only touch/detect spin, not travel through) wormholes between every twinned particle (which is a lot!).

          This gives you non-locality, without breaking FTL communication, and also gives a mechanism for it, that only applies to certain aspects of QM.

      4. Anonymous Coward
        Anonymous Coward

        Re: A different option? You cannot break Bell theorem/observations!

        Maybe it's just nature&maths way of reminding you "entanglement != copying" ?

    3. Anonymous Coward
      Anonymous Coward

      Re: How entanglement really works, how to prove it

      You must have worked very hard on that. Can I suggest for a next effort a codification of the rules of Quiddich?

    4. simonlb

      Re: How entanglement really works, how to prove it

      Just out of interest, is the Earth also flat where you come from?

      1. Anonymous Coward
        Anonymous Coward

        No it's three dimensional

        No the earth isn't flat, nor does it have an extra dimension across which entanglement propagates to fixup Quantum mechanics.

        Simon, it seems to me, that you are unaware of how magical and special Entanglement is, because you did the flat earth thing, without realizing the extra dimensions claimed to support entanglement.

        I'm not saying anything that isn't obvious. The physics here is truely laughable, and you might want to go read up on it to see just how bad it is.

        1. SW10

          Re: No it's three dimensional

          I’d have to assume you’re posting under the AC moniker because you’re doing some breakthrough research in this area and you’re not ready to reveal your hand just yet.

          In telling us to “read up”, could you suggest some titles from your bibliography and/or references?

        2. Anonymous Coward
          Anonymous Coward

          Re: No it's three dimensional

          What is magical about Quantum mechanics? Can you name one property that breaks any observed law? Remember, it does not break thermodynamics or the no FTL communication observations.

          So far it fits in within the observed boundaries of reality.

          Don't mix up people using "Quantum" as an excuse to push philosophical mumbo jumbo with the real hard science facts. One is opinionated junk to sell books to the naive, the other has practical applications.

          1. steelpillow Silver badge
            Boffin

            Re: No it's three dimensional

            To be fair, in his monumental study "The Golden Bough: A Study in Magic and Religion", Sir James Frazer identified several characteristics of magic and one of these was that two objects, once associated with each other, retained that instantaneous association no matter how far apart they might end up. It is a perfect description of quantum entanglement and so describing the phenomenon as magic is quite accurate.

            Coming from the other end, Ed Witten was perhaps the greatest physicist since Einstein. When he discovered a mathematical commonality to a whole slew of gauge and string theories, he dubbed it M theory. One of his most accessible and iconic papers was titled "Magic, Mystery and Matirx", and he explained that the M in M theory stood for all of these.

            So Quantum Magic - yes, you at the front there, come up here and take a bow. Hold your head up, as Rod Argent once wrote (and Russ Ballard sang), and let them burn their eyes on you moving.

            1. werdsmith Silver badge

              Re: No it's three dimensional

              I’m still stuck at double slit.

              1. Headley_Grange Silver badge

                Re: No it's three dimensional

                @werdsmith: When I was a kid, every few years we had a photo of the whole school. Because of the width of the shot the camera was some sort of rotating affair which moved fairly slowly and it was rumoured to be possible, by running fast enough along the back row (who were stood on benches), for one pupil to appear at both ends of the photo. I assume this is how the double slit thing works;-)

                I never saw this in practice. Teachers knew the risk of us trying it and the groundsman was stationed behind the back row to take down, with severe prejudice, anyone who tried it.

                1. STOP_FORTH

                  Re: No it's three dimensional

                  Ha ha! Done that at university.

            2. Schultz

              Quantum magic

              Clarke's Third Law: Any sufficiently advanced technology is indistinguishable from magic.

              I guess the same is true for sufficiently advanced science (that we didn't internalize in high school).

              1. Anonymous Coward
                Anonymous Coward

                Re: Quantum magic

                and the corollary...

                any technology distinguishable from magic is insufficiently advanced.

            3. Steve K Silver badge

              Re: No it's three dimensional

              ..Ed Witten was perhaps the greatest physicist since Einstein

              Was? I thought Ed Witten was still alive? Did someone open the box.......?

        3. Anonymous Coward
          Boffin

          Re: No it's three dimensional

          Once and for all, you don't need extra dimensions to support entanglement. Entanglement is simply a fundamental property of QM, including of nonrelativistic QM. If you think you need extra dimensions for it then, simply, you don't know what you are talking about and you should stop spouting rubbish.

    5. ibmalone Silver badge

      Re: How entanglement really works, how to prove it

      You should go and read up on Bell's inequality, and the experiments done to confirm that it is violated. Then you can come back and spout more tripe if you like, but at least it wont be pretending that such experiments haven't already been done.

      One of the interesting things about Bell is he came up with this clever test expecting it to show something else (local hidden variables), when it didn't he understood what that meant.

      I've yet to see anything that persuades me Hugh Everett wasn't right, quantum state is unchanged by measurement, but superimposed states of macro measurement devices rapidly de-phase preventing their interaction, measurements on entangled particles separated by a space-like interval become orthogonal macro states.

      1. steelpillow Silver badge

        Re: How entanglement really works, how to prove it

        "I've yet to see anything that persuades me Hugh Everett wasn't right"

        I've yet to see anything that persuades me the Flying Spaghetti Monster isn't holding me down with one of His noodly appendages either.

        1. ibmalone Silver badge

          Re: How entanglement really works, how to prove it

          If you like, but the idea there's a magic scale at which state collapse happens seems much more noodly than contemplating that maybe it doesn't and dephasing (which is right there in the maths from the start) produces the same effect at macro level. Weak measurement relies on this already.

          1. Tessier-Ashpool

            Re: How entanglement really works, how to prove it

            Well, there definitely is a scale – the scale of the extremely small, where quantum mechanical effects dominate. Although it’s not really that magical... things that are always seen to be -1 or +1 at a subatomic level (e.g. the spin of an electron) can yield an average value of zero when multiple measurements are made. At the human scale, our perception of reality is based on the interactions of vastly large numbers of quantised atoms.

            1. ibmalone Silver badge

              Re: How entanglement really works, how to prove it

              Ah, this is the opposite of the point I was making. The Copenhagen interpretation attempts to say there is a scale at which this stops happening; the explanation for Shrödinger's cat. The cat is killed by decay of a single nucleus, a quantum event, so it is alive and dead (because that event is a state of quantum superposition), but obviously there is no 'average' between the two states. The idea is then that the act of 'measurement' (whatever that might be) causes superimposed states to collapse to an eigenstate of the measurement operator (the classic Heisenberg uncertainty principle, a state of arbitrarily precise position corresponds to a superposition of states of inversely precise momentum, but probably easier to consider measuring 45 degree polarisation, or circular vs linear polarised states on a photon).

              But weak measurement (explicitly entangling small systems with the state you're measuring) shows the collapse doesn't really happen like that.

              ...or one could take note that the further apart the energy levels of a mixed state are the faster they dephase, and that making measurements couples a superimposed state to the energy states of a larger system. We don't see superimposed states in the macro world because they dephase too fast to influence each other.

    6. Unicornpiss Silver badge
      Meh

      Re: How entanglement really works, how to prove it

      Is this what happens when flat-earthers graduate to quantum physics? Do you stand at the beach and look out at the ocean and say "It's not as big as I thought?"

    7. LyingMan

      Re: How entanglement really works, how to prove it

      If your two ways of disproving quantum entanglement are that straightforward, why no scientist / lab is performing them to disprove? I can see you are but you can't be the only one.

      I remember the aether as medium for light propagation theories which got disproved over time. But there were several people making noises against it. I haven't heard anyone suggest quantum entanglement yet.

    8. Anonymous Coward
      Anonymous Coward

      Re: How entanglement really works, how to prove it

      "By this magic unexplained 'entanglement' connection?"

      Arthur C. Clark was spot on.

      Thank you for pointing it out.

    9. vtcodger Silver badge

      Re: How entanglement really works, how to prove it

      "Researchers then set up a super-sensitive camera capable of detecting single photons which would only take an image when it caught sight of both the photon and its entangled ‘twin’, creating a visible record of entanglement."

      i.e. they filter for some property of two photons, and declare that as entanglement, and the filtering they do is really the cause of the entanglement effect. Let we walk you though how stupid entanglement is and what's actually going on.

      -----

      Ignoring the rest of the post -- which is way beyond my pay grade and apparently controversial ...

      I think the first part (bolded above) might raise a valid issue. As I understand it (or don't), a photon is a massless "particle" conveying one quantum of electromagnetic radiation. How does one image such a thing with a camera? And how does anyone know that the pair of objects imaged are entangled rather than just blundering along in close formation by pure chance?

      Hoping to learn something here.

      1. EarthCitizen

        Re: How entanglement really works, how to prove it

        You image (a) "photons" whenever you open your eyes and see! Vision depends on the eye processing photons. As for "photographing photons" that's another story - we don't have the ability to photograph electrons or even atoms, particles many times bigger than photons.

    10. CommanderGalaxian
      FAIL

      Re: How entanglement really works, how to prove it

      Ya see this is the problem with the Information Age - idiots without any formal qualifications now consider themselves "experts" on a subject because they read something online somewhere.

      Apparently degrees, years of research experience at a top research university and researchers who are happy to submit their work for peer-review and replication & verification amongst suitably and similarly qualified experts at top research institutes globally counts for nothing.

      But 5 minutes of bilge snorted from google counts for everything.

      1. EarthCitizen

        Re: How entanglement really works, how to prove it

        You fail. People are entitled to their opinions, even if they are flat earthers or brexiteers. This is the register not a science journal.

        1. Stoneshop Silver badge
          FAIL

          This is the register not a science journal.

          And opinions are not scientifically validated theories

        2. This post has been deleted by its author

    11. Schultz

      Re: How entanglement really works, how to prove it

      Here is how you can understand entanglement:

      (1) if two particles emerge from a single quantum system _before_ said quantum system has a relevant interaction with anything else, then the two particles can have entangled properties. Note: this is the exception, because things in our universe interact via radiation exchange and collisions. But carefully constructed experiments, e. g. the creation of two photons from one in a nonlinear crystal facilitate this issue.

      (2) if the two particles from (1) are detected before they have a relevant interaction, then the correlated properties can be observed. This requires an experiment that is sensitive to the correlated properties and that can tell which particle pairs belong to one another.

      (3) Correlation breaks down when there is interaction disturbing the correlated system. Take the example of an electron colliding with an atom. Clearly, the collision time and position for both particles is correlated and a suitable experiment might reveal this correlation (a proper quantum mechanical description will be required to predict how this affects measured properties). But these particles are strongly affected by electromagnetic fields and it is very hard to shield them from the environment to observe such correlations. We can therefore, for all practical purposes, ignore the existence of such correlations. Photons interact very weakly with the environment - hence all those entanglement demonstrations are performed with photons.

      Correlation is always tied to the quantum mechanical phase of the wave functions describing the correlated particles. Interactions that disturb the phase destroy the correlation. We therefore talk about 'dephasing' to characterize the time or length scale over which quantum effects can be observed. The stronger the interaction with the environment, the faster the dephasing occurs. To talk about entanglement across the scale of the Universe is nonsense - there is a lot of matter in the universe and matter interacts.

    12. Christoph

      Re: How entanglement really works, how to prove it

      There is no need to respond to people who post on the Internet their proof that Quantum Mechanics does not work.

      Every component of the Internet depends crucially on Quantum Mechanics being by far the most accurate physical theory, most closely corresponding to reality, that we have ever created.

      If Quantum Mechanics were not so incredibly accurate then the Internet could not possibly work. Not just a bit faulty, not a single part of it would function at all.

      If the poster's theory is correct therefore the Internet does not work, therefore the posting does not exist, therefore there is no point in responding to it.

    13. Someoneelsehasmyname
      Thumb Up

      Re: How entanglement really works, how to prove it

      Ok, if you believe in your theory this strongly, how about putting it to the test? It'd be a pretty fundamental shift in how we understand quantum mechanics, so it sounds like it is worth putting in some proper experimental research.

      The steps involved are:

      1) Write up a research proposal

      2) Get your research grant

      3) Perform the research

      4) Publish

      5) Collect your Nobel Prize

  1. Anonymous Coward
    Anonymous Coward

    Scotch eggheads???

    Scotch? Really? Make mine a double.

    1. STOP_FORTH

      Re: Scotch eggheads???

      Scotch-egg heads?

    2. Headley_Grange Silver badge

      Re: Scotch eggheads???

      A.J.P. Taylor's view on Scotch:

      "Some inhabitants of Scotland now call themselves Scots and their affairs Scottish. They are entitled to do so. The English word for both is Scotch, just as we call les français the French and Deutschland Germany. Being English, I use it"

      1. Will Godfrey Silver badge
        Angel

        Re: Scotch eggheads???

        Eh? You call very nationality 'it' - how rude!

      2. veti Silver badge

        Re: Scotch eggheads???

        The difference is that Deutschland and francaise are foreign words in foreign languages. Scots and Scottish, however, are perfectly cromulent English words used by native English speakers speaking English.

        1. Fruit and Nutcase Silver badge

          Re: Scotch eggheads???

          Literally rings our bell: Scotch eggheads...

          Feast on a snack of Scotch Eggs and wash it down with dram or two or Bell's

    3. gimme shelter

      Re: Scotch eggheads???

      "Scotch? Really? Make mine a double."

      ...or a pie. Or broth. Or mist.

      It's a joke. I'm Scottish and it doesn't bother me in the least.

      Aplogies for feeding the troll.

      1. Anonymous Coward
        Anonymous Coward

        Re: Scotch eggheads???

        >It's a joke. I'm Scottish and it doesn't bother me in the least.

        It shouldn't - 'Scotch' is a contraction of 'Scottish' and standard in many Northern and Lowland vernaculars - it's exactly the same word and meaning.

POST COMMENT House rules

Not a member of The Register? Create a new account here.

  • Enter your comment

  • Add an icon

Anonymous cowards cannot choose their icon

Biting the hand that feeds IT © 1998–2021