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Communications Science

Researchers Demonstrate Teleportation Using On-Demand Photons From Quantum Dots (phys.org) 76

Posted by BeauHD from the quantum-communications-networks dept.
An anonymous reader quotes a report from Phys.Org: A team of researchers from Austria, Italy and Sweden has successfully demonstrated teleportation using on-demand photons from quantum dots. In their paper published in the journal Science Advances, the group explains how they accomplished this feat and how it applies to future quantum communications networks. Scientists and many others are very interested in developing truly quantum communications networks -- it is believed that such networks will be safe from hacking or eavesdropping due to their very nature. But, as the researchers with this new effort point out, there are still some problems standing in the way. One of these is the difficulty in amplifying quantum signals. One way to get around this problem, they note, is to generate photons on-demand as part of a quantum repeater -- this helps to effectively handle the high clock rates. In this new effort, they have done just that, using semiconductor quantum dots.

Prior work surrounding the possibility of using semiconductor quantum dots has shown that it is a feasible way to demonstrate teleportation, but only under certain conditions, none of which allowed for on-demand applications. Because of that, they have not been considered a push-button technology. In this new effort, the researchers overcame this problem by creating quantum dots that were highly symmetrical using an etching method to create the hole pairs in which the quantum dots develop. The process they used was called a XX (biexciton)--X (exciton) cascade. They then employed a dual-pulsed excitation scheme to populate the desired XX state (after two pairs shed photons, they retained their entanglement). Doing so allowed for the production of on-demand single photons suitable for use in teleportation. The dual pulsed excitation scheme was critical to the process, the team notes, because it minimized re-excitation.
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Researchers Demonstrate Teleportation Using On-Demand Photons From Quantum Dots More

Researchers Demonstrate Teleportation Using On-Demand Photons From Quantum Dots

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  • I understand some of those words!

    Does this mean we can have a 0 latency network connection regardless of distance some day?

    • No, although it's quite a tease (Score:5, Interesting)

      by raymorris ( 2726007 ) on Tuesday December 18, 2018 @11:50PM (#57828402) Journal

      The rule you may know as "nothing can go faster than light" is actually "information can't be transmitted at more than light speed". You can find ways of measuring "speed" that come out to a value greater than C, but in no case do those allow one to transmit information from here to there at a velocity greater than C. At least not if "here" and "there" are more than an atom apart.

      In quantum theory specifically, there's something called the no-communication theorem.

      One example of a tease is that it's believed using quantum entanglement, two observers at a distance can see the same effect at exactly the same time - as if they both had access to the two ends of a very long string (or cat), and both ends of the string do the same thing at the same time. However, neither end can *effect* the behavior, so they can't send information.

      There are a lot of ways to get excited *thinking* something implies faster than light communication if you understand a little bit of quantum physics.

      • It's true. (Score:1)

        by Anonymous Coward

        Despite all the "teasing" that our science fiction provides, the laws of physics simply do not provide any way that we could build faster-than-light space ships. There will never be an intergalactic community. We are stuck on this rock until the Sun blows up, and that's it.

        Yes it's true that things we have now were science fiction in the past. But they knew far little about physics than we know now. They didn't know what the boundaries were. And we have a very solid grasp of them now.

        And those boundari

        • There will never be an intergalactic community.

          Not of short-lived protoplasm, anyway.

        • I agree that with what we know today, "the laws of physics simply do not provide any way that we could build faster-than-light space ships".

          But what if our current knowledge prevents us from even observing FLT activity. Imagine just 200 years ago. It could have been argued that Europe could not communicate with the US any faster than it takes a person/pigeon/entity to travel that distance. At best, something could be extremely "loud" and shout across the ocean to relay information. The amount of energy/deci

      • The rule you may know as "nothing can go faster than light" is actually "information can't be transmitted at more than light speed".
        If that is the new /. meme: it is wrong.
        Breaking of entanglement, or any other spooking behaviour of entanglement is "transmitted" instantly. Hence the quote of Einstein: this is spooky.

        • > Breaking of entanglement, or any other spooking behaviour of entanglement is "transmitted" instantly.

          There is a relationship between the local qubit and the the distant qubit such that a change to one seems to cause one of several changes to the other.

          Unfortunately, to measure the change and find out exactly what happened to the distant qubit, one requires two classical bits of information about the distant qubit. You can easily find the protocol via Google.

      • You can presuppose ER!=EPR, but until you've a paper on arXix, that's a supposition.

        ER=EPR doesn't violate light speed, it simply says the particles are at the same point. Space isn't absolute, so two observers can see different distances. That's allowed.

        The question is whether it happens.

      • The rule you may know as "nothing can go faster than light" is actually "information can't be transmitted at more than light speed"

        There's another "rule" closer to home that will limit any widespread adoption and/or use by the masses.

        it is believed that such networks will be safe from hacking or eavesdropping due to their very nature.

        The rule is "no un-hackable, secure against government snooping, communications technologies are allowed for the proles."

        If quantum technology can provide individuals with communications that government cannot intercept, track, decrypt, etc, the old "munitions" label for crypto tech in the '80s and '90s will see new life and include bans on domestic use, possession, etc. The US government will never tolera

  • Then we'll never have it... I kid I kid... When do we get the countertop unit?

  • A team of researchers from Austria, Italy and Sweden has successfully demonstrated teleportation using on-demand photons from quantum dots

    What I'm pretty sure this means, is that you can have one place on earth that generates a huge quantity of light, and instead of buying lightbulbs we can all just buy varying clusters of quantum dots for light that just emit the results from the singular source, no matter how far! Pretty awesome.

    Imagine clothes with quantum dots embedded. Luminous!

    No need to wonder if t

    • What I'm pretty sure it means is that a third of Slashdot didn't read the article, a third can't read and a third think this is where you try out for the Morcambe and Wise show.

  • Soon I'll be able to walk into my quantum-dot TV and be teleported to another world. Persona 4 predicted this!

  • "it is believed that such networks will be safe from hacking or eavesdropping due to their very nature."

    Well isn't that special! Truly private communication. But wait, isn't that against government policy? Don't our governments want access to all our communication, without the bother of encryption? Don't they want back doors to our devices?

    But maybe, just maybe, there is an exception for our masters in government, in police work, for corporate boardrooms and financial wheeler-dealers such that they can have the privacy denied to common citizens.

  • On-demand photons...so, this is like quantum Uber? Does it use 3D-printed neural networks?

  • Just make sure (Score:1)

    by Anonymous Coward

    No flies are around

  • The breaking of entanglement is faster-than-light information transmission and thus breaks general relativity.

    Suppose Alice is on a space station around Jupiter, and holds one particle from an entangled pair.

    Suppose Bob, stationed in a space station around Deneb, holds the other particle.

    If the breaking of entanglement results in instant recognition of this breaking, then one can effectively send a signal to both Alice and Bob in faster-than-light speed!

    So something is wrong in all this. Either general rela

    • So something is wrong in all this. Either general relativity is wrong or, more probably, entanglement is not faster-than-light!!!
      General relativity never made any proclaims about entanglements.

      So: why do yo think it is wrong? Which particle of light or energy or mass is transporting the information, which
      is bound to the speed of light? There is none, and as we already know that quantum state transfer is instantly (since 90 years or so) I really wonder why /. is full with ignorants trying to claim it is not

    • No, it isn't FTL, because distance isn't absolute. If ER=EPR, the distance travelled must always be zero regardless of the distance seen by an external observer.

      It isn't necessarily FTL regardless, as an entangled photon is in all states. You're simply collapsing the probability wave to one of those options.

      The other particle is also in all possible states, so the state isn't transmitted. Probability waves aren't information and don't radiate, so don't travel.

  • How much extra does this cost on your cable bill?

  • it is believed that such networks will be safe from hacking or eavesdropping due to their very nature

    But Australia's government will still demand a backdoor...

  • So... is this teleportation or simultaneous photon shedding? The title caused some excitation, but upon reading it, I don't think I'll be having any re-excitation either.

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