back to article Oxford researchers pull off quantum first with distributed gate teleportation

Oxford University researchers have taken a significant step toward large-scale distributed quantum computing by demonstrating the first successful quantum teleportation of a controlled quantum gate between two modules. Published in Nature, the study doesn't claim to be the first to achieve quantum teleportation - after all, …

  1. AMBxx Silver badge
    Unhappy

    Physics A Level

    With articles like this, my A grade at Physics A Level is woefully inadequate. It was nearly 40 years ago. We didn't even get to Einstein's work. All Newton et al.

    1. Andy Non Silver badge

      Re: Physics A Level

      Even with degree level physics, it is tough going. It is very much a highly technical and specialised area requiring true boffins.

      1. Hubert Cumberdale Silver badge

        Re: Physics A Level

        I actually edit papers on this topic, and I don't claim to understand them.

        1. Roj Blake Silver badge

          Re: Physics A Level

          If you think you understand quantum theory, you don't.

      2. Blue Shirt Guy

        Re: Physics A Level

        The trick with quantum physics is to take the exams but never check the results.

        1. Andy Non Silver badge

          Re: Physics A Level

          In case you are handed a dead cat.

    2. Bebu sa Ware
      Big Brother

      Re: Physics A Level

      With articles like this, my A grade at Physics A Level is woefully inadequate. It was nearly 40 years ago. We didn't even get to Einstein's work. All Newton et al.

      Forty+ years ago quantum entanglement was still considered tainted with heresy even after 10 years after J S Bell's 1964 paper and the then recent (1972) early confirmatory experiments.

      Physicists are as daft as the rest of the population - I had to really scratch my head when one presumably more daft stated authoritatively that Bells Inequality was incompatible with the Bohmian interpretation of quantum mechanics (it's not). Bell himself is on record as stating the inherent non-local nature of David Bohm's theory was a significant source of inspiration. See Goldstein's Bell Paper.

      Undergraduate Quantum Mechanics was largely 'don't ask questions - "shut up and calculate.†"' Possibly still is.

      † Apparently from a criticism in What's Wrong with this Pillow?, N. David Mermin Physics Today 42 (4), 9–11<(1989) (pg 1, para 4 (col 2))

    3. Eclectic Man Silver badge
      Unhappy

      Re: Physics A Level

      How do you think I feel? I only got a 'D'.

      (Got an 'A' with merit (2) in the Special paper for Maths though. But all this Quantum Mechanical stuff does my head in.)

      1. Giles C Silver badge

        Re: Physics A Level

        Better than me I only got a e in a level physics.

        And for someone who spends their days designing networks this is very brain scrstchig stuff. Even worse that wireless lan designs.

      2. TheFifth

        Re: Physics A Level

        I got a B at A level Physics some 35 years ago, but the closest I come to doing anything relevant now is watching Brian Cox on the TV. I don't really remember any of it!

        All this quantum stuff is so ridiculously beyond me I can't even see it with a telescope. Interesting though!

        1. Eclectic Man Silver badge
          Joke

          Re: Physics A Level

          watching Brian Cox on the TV

          well, he was excellent in 'Succession'.

          (Sorry, sorry, I know you meant Professor Brian Cox, the one with the hair and previously keyboard player with D:Ream, but I just could not resist. It is a cold wet day in February here in Reading UK, and I needed a little something to cheer me up. Have an upvote by way of apology for my silliness.)

      3. SCP

        Re: Physics A Level

        Well, if my A in A Level Physics taught me one thing it was that there was an awful lot more that I didn't know about a lot of things. It got even worse with my degree. And that was over 40 years ago and they have invented even more physics since then. But I still enjoy hearing about Quantum and Relativistic Physics subjects - typically Don Lincoln on the FermiLab channel or Matt O'Dowd on PBS Space Time. The universe is a weird place (even outside of social media).

    4. teknopaul

      Re: Physics A Level

      86% fidelity is irrelevant: the young boffins have proved they know their stuff, and are guaranteed a job as a result.

      Congrats.

    5. Charlie Clark Silver badge

      Re: Physics A Level

      The quantum stuff is a mixture of extremely advanced maths and finding the abstract ideas to interpret the results, which probably excludes most physicists out there who are happiest when working with the physical world.

    6. Lee D Silver badge

      Re: Physics A Level

      "We deterministically teleport a controlled-Z (CZ) gate between two circuit qubits in separate modules, achieving 86% fidelity,"

      They managed to transmit a particular logic gate implemented using qubits between here and somewhere else, with an 86% chance that it would be there at the end.

      It means they are able to join this bit of a quantum computer with a bit of another quantum computer together. A bit like a distributed server/computation problem - you can make two computers work on the same thing even though they're far apart. However, quantum physics says it doesn't matter how far apart they are anyway. You could literally have computers at opposite ends of the universe and link them like this. That's the old "spooky action at a distance".

      They say themselves that until that "chance" is 99.9% it's probably not practically useful (despite the earlier talk about determinism).

      Basically, they can wire two quantum computers together at an arbitrary distance with a 14% "signal loss" between them.

      (This has been your ELI5 explanation, please don't ask me to make it 100% correct because I can't).

      1. bazza Silver badge

        Re: Physics A Level

        It's a 1 in 1000 error rate. I've no idea if this quantum thingumy jig is different in its tolerance of such error, but I suspect not. In which case, a 1:1000 error rate is pretty dire!

  2. Caver_Dave Silver badge

    Is the end point of this research, two quantum computers, physically separated, but running in-step?

    Useful if one computer is on Earth and the other on the Mars.

    1. werdsmith Silver badge

      “deterministically teleported a fundamental two-qubit quantum gate across two meters of optical fiber, linking two separate quantum modules.”

      I don’t pretend to understand from the article what went on in the experiment but the optical fibre might be a limiting factor on interplanetary use.

    2. Andy Non Silver badge

      I think the essence of it is more about getting enough hardware together to do the computing, unlike traditional CPUs/motherboards where all the components are very close together to maximise data transfer speeds. The quantum computer components don't need to be rammed tight together.

      1. Neil Barnes Silver badge

        But if they're using light to connect, they're going to be speed-of-light limited, no? And so as with electronic computers, smaller = faster?

        (caveat: I am not a quantum boffin, though I did once build a Quantum kit-car).

        1. Inkey
          Coffee/keyboard

          Re- optical cable

          The optical cable from what i can gather is part of the deterministic feed back loop .... how high a probabilty are the qubits entangled ...how lossy/stable is the signal. A way to make predictions on out comes before the gate is "teleported" .

        2. Andy Non Silver badge

          I may be wrong as my knowledge of quantum physics is limited, but I suspect that the speed of light isn't the limiting factor with quantum entangled states. It is a hugely complex and counter intuitive area. I think that the "quantum state information" is transmitted instantaneously between quantum entangled particles, but if you try to use that for sending faster than speed of light communications it wouldn't work as you would effectively get random noise out at the other end.

          1. Andy Non Silver badge

            I'll just add that you are partly correct. The speed of light would be a limiting factor in setting up the initial quantum states and the physical separation of the entangled particles. This is the equivalent of loading a calculation into RAM ready to be processed. But the actual execution of the calculation by the quantum computer would be done instantaneously.

        3. Brewster's Angle Grinder Silver badge

          I haven't looked at the paper, but the defining thing about entanglement is it's "faster than light" (non local). However additional information is needed to unscramble it, so useful information can't travel FTL. Which is an elaborate way of agreeing it will be light-limited.

          Explaining the FTL bit is where your chosen interpretation of Quantum Mechanics comes in: what are you willing to sacrifice?

          1. Rich 11

            However many black cockerels I sacrificed to Lucifer, my grasp of quantum mechanics still wouldn't advance by very much.

        4. Giles C Silver badge

          Which model?

    3. Bebu sa Ware
      Big Brother

      Although Albert is still on the job

      Is the end point of this research, two quantum computers, physically separated, but running in-step?

      Useful if one computer is on Earth and the other on the Mars.

      Even with entangled systems you still cannot transmit information faster than light so in future we will still have to wait 4 to 24 minutes to receive the edicts of the sometime Karen of Space and future autocrat of Mars.

      1. Charlie Clark Silver badge

        Re: Although Albert is still on the job

        I think there's also a paradox in there about how you'd prove it…

        I think that, one day, we might find effects that look like FTL communication might be possible but it'll turn out to be a "dimensional issue" or never applicable so getting the results of the 3:30 at Chepchester before the start of the race is still a no-goer.

    4. Paul Herber Silver badge

      They must be bonded in some way, perhaps watching Quantum of Solace will help.

      1. Charlie Clark Silver badge
        Coat

        Groan

        I believe this is yours – it's got a copy of Puns for Dummy in the pocket…

        1. Paul Herber Silver badge

          Re: Groan

          That's not mine. Mine is a first edition with the torn jacket.

  3. sabroni Silver badge
    Happy

    across two meters of optical fiber

    These twats need to watch Star Trek if they think that is teleportation.

    1. m4r35n357 Silver badge

      Re: across two meters of optical fiber

      Yep. Those guys have also perfected faster-than-light travel & artificial gravitation. Why is no-one looking into this?

      1. Anonymous Coward
        Anonymous Coward

        Re: across two meters of optical fiber

        And nobody in Star Trek ever needed to go to the toilet either, so there's more research needed.

        1. cosymart
          Holmes

          Re: across two meters of optical fiber

          That might be because nobody could find them. Why do you think everyone is walking about very quickly?

          1. Neil Barnes Silver badge

            Re: across two meters of optical fiber

            Obviously, too much tea, earl gray, hot.

            1. m4r35n357 Silver badge

              Re: across two meters of optical fiber

              Grey, not Gray

              https://en.wikipedia.org/wiki/Earl_Grey_tea

        2. Hubert Cumberdale Silver badge

          Re: across two meters of optical fiber

          I refer you to The Meaning of Liff:*

          "Peakirk n. One who regularly points out that there are no lavatories on the USS Enterprise."

          *(Actually, having checked, I find it's in Afterliff.)

          1. The Oncoming Scorn Silver badge
            Holmes

            Re: across two meters of optical fiber

            According to some "plans" I've seen over the years, the original series Enterprise Bridge had a service channel duct as a buffer between the rear of the bridge consoles & inner\outer hull skins.

            The bridge lavatories apparently are discreetly placed to the right hand (& left?) side of the main view screen extending into that service access tunnel..

            I don't know about you, but when I go to download my personal log, when I'm done I wouldn't want to come out to at least 3 pairs of command crew eyes on me as I evacuate the facility, especially if there are Klingons on the main screen at the time.

            1. Neil Barnes Silver badge

              Re: across two meters of optical fiber

              Surely, the Klingons are on the starboard bow?

          2. dmesg

            Re: across two meters of optical fiber

            This is one thing that Babylon 5 got right. There's even a scene where Sheridan and Garibaldi are standing at the urinals, in order to meet and communicate as conspirators in a way that won't draw attention to their having met.

            1. Benegesserict Cumbersomberbatch Silver badge

              Re: across two meters of optical fiber

              So they were boldly going where no-one had gone before?

        3. FIA Silver badge

          Re: across two meters of optical fiber

          ...so you're telling me I've misunderstood 'Captains Log'?

          I always thought that's what Picard was doing during the credits.

        4. Dr Kerfuffle

          Re: across two meters of optical fiber

          They don't need to go to the toilet in Star Trek because they can transport whatever is in their bladder straight out into space. Although hopefully they'd work out how to avoid beaming out your bladder at the same time (or other parts of your guts!). They should also be able to make light bulbs containing a perfect vacuum by beaming out all of the air from them.

          1. Hurn

            Re: across two meters of optical fiber

            Why beam it into space? More likely destination is the "organic matter" storage tank for the food replicators.

            Sign seen in the head: "Flush twice, it's a long way to the Mess Deck."

      2. Anonymous Coward
        Anonymous Coward

        Re: across two meters of optical fiber

        They also invented the body scanner that inspired Sir Peter Mansfield to create the MRI body scanner.

      3. Charlie Clark Silver badge

        Re: across two meters of optical fiber

        There's a conspiracy to keep it only for the Lizard People!

    2. Eclectic Man Silver badge
      Happy

      Re: across two meters of optical fiber

      Or 'Galaxy Quest'

    3. Anonymous Coward
      Anonymous Coward

      Re: across two meters of optical fiber

      More seriously, why *do* they call it teleportation when a fibre link is involved?

      1. Andy Non Silver badge

        Re: across two meters of optical fiber

        Think of the fibre link as background, but necessary infrastructure. While entangled particles need to separate via the fibre link, they are not what is being "teleported". What does get subsequently teleported is the quantum entanglement state of one of the particles to the other particle, and this happens instantaneously and doesn't use the fibre link.

        1. Anonymous Coward
          Anonymous Coward

          Re: across two meters of optical fiber

          Ahhh! That makes it much clearer. Thanks.

          (I posted AC as my question sounded stupid!)

  4. that one in the corner Silver badge

    Grover's Algorithm

    Come for the entanglement, stay for the Sesame Street jokes.

    (Sorry, that was the closest I came to understanding the details in this story)

    1. Anonymous Coward
      Anonymous Coward

      Re: Grover's Algorithm

      Ahh, yes, one of the gates is near, and the other gate is (step step step step step...) far.

  5. TRT Silver badge

    Distributed gate teleportation?

    That explains why our back alley was unprotected after the recent storm and there wasn't a trace of t'wood from t'ole.

  6. TRT Silver badge

    Starship Titanic

    "for large computations, the probability of successfully completing a computation without any failures becomes exponentially small."

    In theory, the infinite improbability drive would make it infinitely improbable that anything would go wrong. It was not successful, however, ending in a "Spontaneous Massive Existence Failure." This was because, in these earlier times when the nature of improbability was less well understood, it was not appreciated that any event that is infinitely improbable will, by definition, occur almost immediately.

    1. TRT Silver badge

      Re: Starship Titanic

      So whilst it's possible to generate a small but finite amount of quantum entanglement, the probability of generating the infinite amount of entanglement they'd need for a usable and error free quantum computer of the kind that is capable of working out the sorts of universal problems that they wanted to use it for would, in fact, be exponentially small. So all you'd have to do is work out exactly how many qubits you'd need, feed that number into the trapped-ion quantum computer, give it a fresh cup of really cold liquid nitrogen, and turn it on.

  7. Long John Silver Bronze badge
    Pirate

    Ask Sabine Hossenfelder

    I shall wait to see whether Sabine Hossenfelder has anything to say about this.

    [YouTube channel, but better viewed on FreeTube]

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