Quantum Teleportation Used To Distribute a Calculation (arstechnica.com) 23
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.
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.
Re: (Score:2)
> send Morse code across the galaxy
No, that's too convenient to work. Quantum is a tease, proving that God is female.
Re: with this (Score:2)
Re: (Score:2)
dotdotdot dash dotdotdash dashdotdashdot dashdotdash / dashdashdash dashdot / dashdotdot dashdashdash dashdashdash dashdash dot dashdotdot / dotdashdashdot dotdashdotdot dotdash dashdot dot dash dashdashdotdotdashdash / dotdotdotdot dotdash dotdotdotdash dot / dash dashdashdash dotdashdash dot dotdashdotdot dashdashdotdotdashdash / dashdotdashdot dashdashdash dashdash dot / dashdashdotdash dotdotdash dotdot dashdotdashdot dashdotdash
I tried to wrap my head around this (Score:2)
Re: (Score:2)
Re: (Score:2)
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
Re: (Score:2)
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.
Quantum deportation (Score:2)
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.
Re: Quantum deportation (Score:2)
Just great (Score:2)
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.
Re: (Score:2)
Nah, just outlaw quantum entanglement.
Re: (Score:2)
Why outlaw it? Trump can sign an executive order to define quantum entanglement as between a hadron and two bosons.
This is going to (Score:2)
...use up all the cats. They are Schrodingerizing the pets!
Re: (Score:2)
The way things are going lately, we are basically creating supercats immune to quantum poisoning and bird flu.
A lot of people wish they could teleport Control Z (Score:1)
6 feet!?!?! (Score:2)
WHOA, two different objects that were located six feet apart COULD HAVE BEEN IN DIFFERENT ROOMS?!?!!? OMG, THANKS FOR BRINGING THAT TO MY ATTENTION
i wish (Score:2)