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Supercomputing

Quantum Teleportation Used To Distribute a Calculation (arstechnica.com) 58

Posted by BeauHD from the two-is-better-than-one dept.
An anonymous reader quotes a report from Ars Technica: In today's issue of Nature, a team at Oxford University describes using quantum teleportation to link two pieces of quantum hardware that were located about 2 meters apart, meaning they could easily have been in different rooms entirely. Once linked, the two pieces of hardware could be treated as a single quantum computer, allowing simple algorithms to be performed that involved operations on both sides of the 2-meter gap. [...] The Oxford team was simply interested in a proof-of-concept, and so used an extremely simplified system. Each end of the 2-meter gap had a single trap holding two ions, one strontium and one calcium. The two atoms could be entangled with each other, getting them to operate as a single unit.

The calcium ion served as a local memory and was used in computations, while the strontium ion served as one of the two ends of the quantum network. An optical cable between the two ion traps allowed photons to entangle the two strontium ions, getting the whole system to operate as a single unit. The key thing about the entanglement processes used here is that a failure to entangle left the system in its original state, meaning that the researchers could simply keep trying until the qubits were entangled. The entanglement event would also lead to a photon that could be measured, allowing the team to know when success had been achieved (this sort of entanglement with a success signal is termed "heralded" by those in the field).

The researchers showed that this setup allowed them to teleport with a specific gate operation (controlled-Z), which can serve as the basis for any other two-qubit gate operation -- any operation you might want to do can be done by using a specific combination of these gates. After performing multiple rounds of these gates, the team found that the typical fidelity was in the area of 70 percent. But they also found that errors typically had nothing to do with the teleportation process and were the product of local operations at one of the two ends of the network. They suspect that using commercial hardware, which has far lower error rates, would improve things dramatically. Finally, they performed a version of Grover's algorithm, which can, with a single query, identify a single item from an arbitrarily large unordered list. The "arbitrary" aspect is set by the number of available qubits; in this case, having only two qubits, the list maxed out at four items. Still, it worked, again with a fidelity of about 70 percent.

While the work was done with trapped ions, almost every type of qubit in development can be controlled with photons, so the general approach is hardware-agnostic. And, given the sophistication of our optical hardware, it should be possible to link multiple chips at various distances, all using hardware that doesn't require the best vacuum or the lowest temperatures we can generate. That said, the error rate of the teleportation steps may still be a problem, even if it was lower than the basic hardware rate in these experiments. The fidelity there was 97 percent, which is lower than the hardware error rates of most qubits and high enough that we couldn't execute too many of these before the probability of errors gets unacceptably high.
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Quantum Teleportation Used To Distribute a Calculation More

Quantum Teleportation Used To Distribute a Calculation

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  • and yet still struggle to think about what kind of real world applications this would have, other than "oh that's neat". Maybe this is a problem looking for a solution or just academic exploration for the sake of academic exploration, and some PhD's? No idea but if anyone can tell me if this is going to benefit me in some way in the future - I'd love to hear it!

    • Re: (Score:2)

      by Gavino ( 560149 )
      I meant "solution looking for a problem". My brain is too quantum-entangled to think straight.

    • I don't know either. But I think maybe it means that in the near future, computer processing will be so fast that no form of encryption will be strong enough to be useful for anything. All data that flows over the internet will be completely open and visible to criminals and governments alike. No bank account's funds, online identity, or really anything will be safe.

      We will have to make some hard adjustments, back to an earlier day in some respects. Things will take longer, and it will be painful. Lots

    • I doubt we'll see any commonly used application for it any time soon, but I do believe it's a stepping stone in gaining more knowledge about physics and how everything around us works.
      Every bit of knowledge leads to something else to learn.

    • Re: (Score:3)

      by mattr ( 78516 )

      IANAP but just skimming the summary and the paper's abstract this implies you can link two quantum computers to make one big one. Think of it like having two graphics cards on your PCI bus to speed up computation. tldr; I don't know if it means you can build a 50 qubit computer out of five 10 qubit computers, and the 70% accuracy will have to improve to get beyond a factor of two, but still this is a very interesting finding. They are building the foundation of a new kind of computer. I'd expect a working q

      • Re: (Score:2)

        by mattr ( 78516 )

        p.s. sorry the 70% accuracy was apparently just due to stuff on the endpoints, the actual teleportation-transmission is near 100% it seems. Someone who actually read the article feel free to correct.

        • Re: (Score:2)

          by HiThere ( 15173 )

          IIUC, they think the inherent accuracy is about 97%.. That's going to mean the need for a lot of error correcting code, which is normal for quantum qbits. (Actually the claim is that this is better than normal, but it's just one step of the process.)

    • I think with quantum computers we are still very much in the basic science domain. Something will probably come out of it pretty revolutionary in 30 to 50 years. But that's just kind of the nature of doing basic science. It's a tree you plant where you're never going to sit in it's shade. And the reason we have the things we do today is because somebody else planted those trees for us
    • There is none and they deluding themselves. Jacob Barandes has basically successfully mathematically replaced traditional wave function quantum mechanics with indivisible stochastic processes. Traditional physicals thinks a measurement is absolute and this is why they think there is entanglement and collapse of wave function. As shown by Brandes - the actual issue is just they are measuring one individual stochastic processes *another* and this results in a appearance of entanglement etc when there is n

  • Quantum deportation (Score:3)

    by backslashdot ( 95548 ) on Saturday February 08, 2025 @12:06AM (#65151293)

    I don't like illegals takin' arr jerbs either, but this is going too far .. they're just trying to feed their families and all work helps the economy.

    • A quantum family would be very very tiny.

  • Just great (Score:3)

    by fahrbot-bot ( 874524 ) on Saturday February 08, 2025 @12:18AM (#65151307)

    Oxford University describes using quantum teleportation to link two pieces of quantum hardware that were located about 2 meters apart, meaning they could easily have been in different rooms entirely.

    At some point instead of just air-gapping a system we'll have to put it in a TARDIS and jump to the future or alternate Universe -- with no guarantee that'll work either. And TARDISes don't grow on trees you know. Instead of Dr Who we'll need Dr How to consult with Dr Where and/or Dr When.

    • Nah, just outlaw quantum entanglement.

    • It's not air-gapped. There's a fiber cable linking the two boxes.

      It's therefore not teleportation either. Gotta love ignorant journalism.

      • Re: (Score:2)

        by HiThere ( 15173 )

        Nah. That's a special meaning of teleportation, which is "sort of" reasonable, given that they're otherwise no close analog. It's like the C++ move operation, an just like in C++ the physical objects aren't being moved, so they didn't want to use move. (The quantum use of teleportation is older than the C++ use of move. But I agree that "move" is closer to the meaning than "teleport", going by common use meanings.)

    • Re: (Score:2)

      by rossdee ( 243626 )

      TARDISes don't grow on trees you know

      But the Masters Tardis can look like a tree, because it doesn't have a broken camoflage system

  • ...use up all the cats. They are Schrodingerizing the pets!

    • The way things are going lately, we are basically creating supercats immune to quantum poisoning and bird flu.

  • two pieces of quantum hardware that were located about 2 meters apart, meaning they could easily have been in different rooms entirely.

    WHOA, two different objects that were located six feet apart COULD HAVE BEEN IN DIFFERENT ROOMS?!?!!? OMG, THANKS FOR BRINGING THAT TO MY ATTENTION

    • Re: (Score:2)

      by Mal-2 ( 675116 )

      The computer I'm using right now is in a different room from me and all of its attached hardware. For this massive leap forward, I just had to make a hole through the wall smaller than an electrical junction box, so I can glue blank panels over the hole later. Where's my credit?

  • i wish they stop using well established scifi terminology for petty attempts at different approach to wifi

    • Re: (Score:2)

      by HiThere ( 15173 )

      It's not like wifi. OTOH, it is like the C++ move operation. But I'm rather sure that the quantum folk started using "teleport" for that operation before the C++ folk released a version of C++ that included the move operation, so they didn't have that to use as an analogy.

  • Imagine the possibilities!

  • The key part: (Score:3)

    by Qbertino ( 265505 ) <moiraNO@SPAMmodparlor.com> on Saturday February 08, 2025 @05:47AM (#65151497)

    "Because classical information needs to be sent, quantum teleportation cannot occur faster than the speed of light."

    Bummer.

    • "Because classical information needs to be sent, quantum teleportation cannot occur faster than the speed of light."

      Bummer.

      Then don't send it in Greek, dummy!

    • Sending anything to another location breaks the entire idea of teleportation. The only exemption there is sending the initial entanglement for basic setup.

      If you must continue sending anything at all, this is not teleportation.

      While I am ranting, it reads to me that this just syncs two machines into the same state - ok, but that's not teleportation either. It's just sharing a (hypothetically secure) serial number to seed the machines to operate with similar results.

  • Yes, you may be able to do computations "some place else". But if this could be used for communication, most of Quantum Theory goes out the window. The only exception is if this can only be used practically for short-distance low-bandwidth communication and hence is effectively useless. There is another process that can likely be used for FTL over short distances: the Tunnel Effect. Problem with it is that you need massive amounts of energy for very short distances. While that is not (yet?) in Quantum Theor

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