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Qubit Teleportation Paves the Way for Galaxy-Spanning Communications

Microchip
Microchip (Image credit: Shutterstock)

As you approach the orbit of your new home planet, Gliese 667CC (opens in new tab), you realize you made a terrible, terrible mistake: you didn’t download the latest firmware update for your ships’ communication protocols. 

While this would be a secondary concern around Earth’s orbit, where the servers holding the installable package reside and radio communications are speedy enough (opens in new tab) to make do, things are different when you’re 22 light-years away from humanity’s cradle. There’s no way for you to download an update for your ships’ protocols promptly; with no communications handshake happening, you’ll have to pay a hefty fine for the military ships sent to investigate your lack of response to the official channels. You haven’t even crossed Gliese’s atmosphere, and you’re already in debt. Ouch.

Fortunately, researchers with the Delft University of Technology in the Netherlands have furthered the road towards an eventual quantum internet. The effort, published earlier this week in Nature (opens in new tab), drives us ever-so-slightly forward toward an intra-and, perhaps, extra-planetary communications network.

When achieved, this quantum network will be able to operate at instantaneous speed, teleporting information between places in a secure, interference-and-snooping-free way. It happens because anyone trying to intercept qubit operations or read the qubit state would introduce errors in the computation or even lead the entangled qubits to decohere, losing the information in the process - a quirk dubbed the Observer Effect (opens in new tab) in quantum physics.

“This means that the quantum computer can solve your problem and that it does not know what the problem is,” said Tracy Eleanor Northup, a researcher at the University of Innsbruck’s Institute for Experimental Physics. “It does not work that way today. Google knows what you are running on its servers.”

The research takes advantage of the entanglement property of quantum physics, which allows for the “marriage” of two qubits so that changes affecting one of them automatically replicate them in the other - irrespective of such mundane concerns as distance. As a result, the qubits are no longer independent: they’re now a single system like a married couple.

Delft university's qubit design

Diamond samples inside one of the quantum computers at the Delft University of Technology. Gold structures on the diamond surface allow control of the quantum processor. (Image credit: Mateo Pompili for QuTech)

While entanglement between two qubits has been conquered for a while now, the researchers finally managed to expand the maximum number of entangled qubits from two to three - opening up the door for multilateral, instead of simply bilateral, communication.

With quantum computing still being a nascent field, there are several ways to produce qubits - from electrons to quantum dots, passing through ion chains and Microsoft's exotic topological qubits; there are several approaches and materials with different strengths and weaknesses. For their experiment, which entangled the three qubits in systems 60 feet apart from each other, Dr. Hanson and his team used a nitrogen vacancy center — a tiny empty space in a synthetic diamond to trap electrons.

But entanglement has already been shown to be viable (opens in new tab) up to 1,203 kilometers (748 miles) apart - and future research will focus on scaling the distance between entangled qubits while increasing the number of entangled "network nodes."

This development, in turn, could enable a veritable quantum internet, where information only needs to be updated in a single physical location - such as a specific ship manufacturer's headquarters - with instantaneous propagation across the network of entangled qubits. Wouldn't that be handy for your firmware update antics above the skies of Gliese 667CC?

Francisco Pires is a freelance news writer for Tom's Hardware with a soft side for quantum computing.

  • thisisaname
    Very nice but it is rather "easy" to DoS it, all you need to do is try and read it and the network goes down.
    Reply
  • derekullo
    I don't trust this spooky action at a distance

    Having said that, physics doesn't care what I believe :P
    Reply
  • Alvar "Miles" Udell
    Einstein: Nothing can go faster than the speed of light!

    Quantum physics: Hold my qubit.
    Reply
  • pixelpusher220
    Step 2: galaxy comms

    what's step 1? it takes a while
    Reply
  • Xenophage
    Information cannot travel faster than the speed of light, unfortunately. But a quantum Internet is promising for security and privacy reasons.
    Reply
  • Alvar "Miles" Udell
    Quantum physics and general relativity don't currently mesh, so it is possible in the world of QP that information can travel faster than the speed of light because it's governed by a different set of laws.
    Reply
  • TJ Hooker
    Alvar Miles Udell said:
    Quantum physics and general relativity don't currently mesh, so it is possible in the world of QP that information can travel faster than the speed of light because it's governed by a different set of laws.
    Nope, you still can't have faster than light communication even with quantum effects like entanglement. In the case of this article, they still needed a classical channel to transfer information between the two nodes. Only once the information has passed through that classical channel (which is limited by the speed of light), can the quantum teleportation be performed. The result being presented isn't that they can transmit information faster than light, it's that they are able to transmit data over a quantum 'channel' with higher fidelity than would have been possible over a classical channel.
    Reply
  • TheVoiceOfReason
    TJ Hooker said:
    Nope, you still can't have faster than light communication even with quantum effects like entanglement. In the case of this article, they still needed a classical channel to transfer information between the two nodes. Only once the information has passed through that classical channel (which is limited by the speed of light), can the quantum teleportation be performed. The result being presented isn't that they can transmit information faster than light, it's that they are able to transmit data over a quantum 'channel' with higher fidelity than would have been possible over a classical channel.
    Incorrect. You are confused about what it means to "travel" faster than the speed of light. Information can most definitely get from point A in the universe to point B in the universe faster than it would take light to conventionally travel between those two points. One such way is via a wormhole.

    "Traveling" at the speed of light means that the "thing" passes through all points in space between points A and B. In the case of quantum entanglement, the information never actually travels at all. There is no "faster than light" aspect to quantum entanglement. It simply happens instantaneously without any travel.

    If you want to consider the "travel" aspect of it, the "traveling" happens when the two entangled items are separated by distance. You are correct in that the transceivers cannot travel faster than the speed of light apart from each other. Once they do, however, the information no longer actually travels anywhere.

    I'm not going to waste time trying to convince you about the science behind it. Even Einstein didn't fully grasp spooky action at a distance. We don't understand it well enough to make use of it yet, so there is no point in you trying to argue that it's impossible. Just because we haven't proven we can do it doesn't mean we can't.
    Reply
  • NinoPino
    TheVoiceOfReason said:
    Incorrect. You are confused about what it means to "travel" faster than the speed of light. Information can most definitely get from point A in the universe to point B in the universe faster than it would take light to conventionally travel between those two points. One such way is via a wormhole.

    "Traveling" at the speed of light means that the "thing" passes through all points in space between points A and B. In the case of quantum entanglement, the information never actually travels at all. There is no "faster than light" aspect to quantum entanglement. It simply happens instantaneously without any travel.

    If you want to consider the "travel" aspect of it, the "traveling" happens when the two entangled items are separated by distance. You are correct in that the transceivers cannot travel faster than the speed of light apart from each other. Once they do, however, the information no longer actually travels anywhere.

    I'm not going to waste time trying to convince you about the science behind it. Even Einstein didn't fully grasp spooky action at a distance. We don't understand it well enough to make use of it yet, so there is no point in you trying to argue that it's impossible. Just because we haven't proven we can do it doesn't mean we can't.

    Tj Hooker is not confused at all.
    If you have two entangled photons, and you want to use this system to transfer information, let's say at a light year of distance, the first thing to do is to create the entangled system here on earth, than transfer one particle to the destination system. The transfer of the particle, in this case a photon, must obey relativity, so you need a year to transfer the information and only after that you can leverage the entanglement.
    Moreover, there is no way to change the state of the components of the entangled system, you can only read the state and do collapse the "wave function".
    About the "spooky distant action", Einstein is not wrong. Two entangled particles should be intended as an unique entity, and not as two distinct particles, so there is no real "distant action" .
    Reply
  • TheVoiceOfReason
    NinoPino said:
    Tj Hooker is not confused at all.
    If you have two entangled photons, and you want to use this system to transfer information, let's say at a light year of distance, the first thing to do is to create the entangled system here on earth, than transfer one particle to the destination system. The transfer of the particle, in this case a photon, must obey relativity, so you need a year to transfer the information and only after that you can leverage the entanglement.
    Moreover, there is no way to change the state of the components of the entangled system, you can only read the state and do collapse the "wave function".
    About the "spooky distant action", Einstein is not wrong. Two entangled particles should be intended as an unique entity, and not as two distinct particles, so there is no real "distant action" .
    Wrong. That's not how a qubit works. You don't make a qubit, move it, then make a new one. Once the technology is perfected, the two devices need to be separated only once. Then, the state of one is immediately reflected in the other. You're confusing the quantum transport of keys over fiber optics with quantum computing qubits. I know it's a lot to try to follow, so I don't fault you for not understanding it.

    Once two entangled communications devices are separated by 22 light years, the new data no longer has to travel at all. It's already there. You have Qa1 entangled with Qa2 and Qb1 entangled with Qb2. Qa is altered on Earth and read on the other planet. Qb is altered on the other planet and read on Earth. The speed of light is no longer involved in the equation. The states of the qubits change instantaneously. There is no "travel" of the information. It's simply there.

    Quantum physics is confusing. That's why Einstein's theory breaks down at that level. We don't completely understand it all yet, though things like wormholes still work. The data doesn't travel through the universe. It traverses a quantum tunnel that is not bound by relativity.
    Reply