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Science Technology

First Object Teleported From Earth To Orbit (technologyreview.com) 212

Researchers in China have teleported a photon from the ground to a satellite orbiting more than 500 kilometers above. From a report: Last year, a Long March 2D rocket took off from the Jiuquan Satellite Launch Centre in the Gobi Desert carrying a satellite called Micius, named after an ancient Chinese philosopher who died in 391 B.C. The rocket placed Micius in a Sun-synchronous orbit so that it passes over the same point on Earth at the same time each day. Micius is a highly sensitive photon receiver that can detect the quantum states of single photons fired from the ground. That's important because it should allow scientists to test the technological building blocks for various quantum feats such as entanglement, cryptography, and teleportation. Today, the Micius team announced the results of its first experiments. The team created the first satellite-to-ground quantum network, in the process smashing the record for the longest distance over which entanglement has been measured. And they've used this quantum network to teleport the first object from the ground to orbit. Teleportation has become a standard operation in quantum optics labs around the world. The technique relies on the strange phenomenon of entanglement. This occurs when two quantum objects, such as photons, form at the same instant and point in space and so share the same existence. In technical terms, they are described by the same wave function.
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First Object Teleported From Earth To Orbit

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  • by CajunArson ( 465943 ) on Tuesday July 11, 2017 @09:43AM (#54785935) Journal

    Outside of an arbitrary definition that says a photon is an object because we say so, a photon is most certainly not an "object" using any ordinary definition of the term or even a definition that the vast majority of physicists would use (i.e. than an "object" has mass, which photons most certainly don't have or else they would never be able to travel at light speed).

    • by turkeydance ( 1266624 ) on Tuesday July 11, 2017 @09:51AM (#54785975)
      the photon objects.
    • I was going to ask the same question, also thinking that a photon does not qualify as an 'object' either; story is nigh-unto clickbait for that reason.
      • by jandrese ( 485 )
        Seemed like pretty standard technical reporting from a major news agency. In other words all of the details are wrong and/or overstated.
        • You mean like how they perpetually misuse the term 'Artificial Intelligence'?
          • It should not surprise you. Both the words "artificial" and "intelligence" are deep philosophical questions.

            Given that artificial flavors are often quite distinguishable from the original they are trying to emulate, I am willing to accept that artificial intelligence is not equivalent to human intelligence or even mammalian intelligence. But I still expect there to be some reasonably high bar for what is intelligence even if it is artificial. Systems that employ problem solving and machine learning even if

            • The problem is when the media and the general public conflate 'machine learning' and the other things that are the more technically correct terms for what they're creating right now, with walking, talking, thinking, reasoning, self-aware, fully 'conscious' androids, like something from an Isaac Asimov novel, which is what's going on now. I'm fully convinced that there are is a sizable group of people out there that really believe that their so-called 'self driving car' is going to have full-on conversations
    • Yes it is : Photon photon = new Photon();

    • by Khyber ( 864651 )

      Energy equals mass times the speed of light squared.

      Thus, for a photon to have energy, it must have some mass.

      Otherwise E=MC^2 is wrong.

  • by H3lldr0p ( 40304 ) on Tuesday July 11, 2017 @09:54AM (#54785999) Homepage

    in order to understand everything that was going on with the experiment. I wish the traditional media good luck in trying to translate all of that into an article for mass consumption.

    • by bazorg ( 911295 )

      OH don't worry, they'll use some Star Trek clips and a car analogy and then move on to some other subject :)

    • keep an eye on ArsTechnica. They may cover this as well, and they do a pretty good job making this stuff comprehensible to the average Joe.
  • by 140Mandak262Jamuna ( 970587 ) on Tuesday July 11, 2017 @10:02AM (#54786059) Journal
    If you are going to hype like this, why aim so low? Might as well tack on cure for cancer and solving world hunger.
  • How do they know it's the same photon?
    • Same photon/different photon with exactly the same properties (of which a photon has a limited and fixed number)... it's somewhat arbitrary and philosophical as to whether that makes it the same photon.

      • Properties of a photon also include its location in space. There are plenty of photos with identical properties save for their location in space.

    • In quantum mechanics, photons are indistinguishable. They are all excitations of the the same quantum field, so it isn't meaningful to assign individuality to each photon. Mathematically, if you interchange two photons, you have done nothing to the state of the photonic quantum field.

    • They asked it.

  • by gotan ( 60103 ) on Tuesday July 11, 2017 @10:07AM (#54786095) Homepage
    What it means is, that the quantum state from a particle on Site A is transferred to a particle on Site B. This involves an entangled state of two particles in A and B. Depending on the experimental set up the entangled particle in site B may be the object the quantum state is transferred to. The "teleportation" involves a measurement in Site A, and to completely transfer the quantum state to B one needs the (classical) result of this measurement at site B.
    • What it means is, that the quantum state from a particle on Site A is transferred to a particle on Site B. This involves an entangled state of two particles in A and B. Depending on the experimental set up the entangled particle in site B may be the object the quantum state is transferred to. The "teleportation" involves a measurement in Site A, and to completely transfer the quantum state to B one needs the (classical) result of this measurement at site B.

      Ok, can you put this into layman's terms, and tell

    • The end result is physically and fundamentally impossible to distinguish from "real", sci-fi teleportation though.

      • by Baloroth ( 2370816 ) on Tuesday July 11, 2017 @12:06PM (#54787317)

        Not really. The problem is that we didn't take a photon in the lab, and create an identical photon in space. We took a photon in the lab, created a photon in space, then made the photon in space identical to the photon in the lab. That's a bit like taking a block of marble and carving it into *exactly* the same shape as, say, Michelangelo's David, then claiming we "teleported" the statue. Even if the final product is molecule for molecule identical, few people would call it "teleportation". Teleportation would involve taking the particles from one location and transferring them to the other, in some kind of stream or through a wormhole or something. Note that this is probably impossible.

        The key to quantum "teleportation" is that particles are indistinguishable except for a couple of quantum numbers, so if we take a particle and force it to have the same numbers as another particle, we've "teleported" it. Except that we can also distinguish particles based on position. Yes, it's true that you can take two electrons in two hydrogen atoms, exchange them, and you'd never know the difference. But we can still say the electron in that hydrogen atom over there is not the same electron as the electron in this hydrogen atom a million miles away. This isn't just a philosophical distinction: the two electrons really are different (i.e. have different quantum wavefunctions), at a physics level.

    • by Daetrin ( 576516 )
      So i understand that in order to "fully reconstruct" the state of the qubit you need a "side channel" to transmit the classical data about the original state. This supposedly means that superluminal communication is impossible.

      However can you not even tell that quantum teleportation has taken place at all until the classical information arrives and tells you it happened? If you can't observe that anything has changed at all until someone else tells you it happened it seems to be a bit of a sham.

      However
      • by nickersonm ( 1646933 ) on Tuesday July 11, 2017 @11:11AM (#54786737)

        You cannot tell that anything has happened by just looking at one of the entangled particles, no.

        On a very brief and undetailed level, entanglement just says that measurements of particles A & B are correlated. What happens in an entangled measurement is vaguely like this:

        1. Particles A & B are two-state systems: when measured in a certain way, they can either be a 1 or a 0. Before being measured, they are some combination of 1 and 0 and thus have a probability of being measured 1 or 0, but are not either.
        2. Particles A & B are now entangled and in a state such that each individually has a 50% chance of being either 1 or 0.
        3. Without being measured, B is moved to a long distance away.
        4. A is measured.
        5. When B is measured, it will be !A (100% of the time if the entanglement is perfect).
        6. The important part is that the people measuring B don't know what A was until someone tells them via a classical channel.
        7. If one makes continuous measurements of a stream of Bs (B1, B2, ...), they see a random pattern of 1s and 0s.
        8. The people measuring a stream of As see a random pattern of 1s and 0s, but the interesting part is the A1...An is exactly !(B1...Bn) (anticorrelated)! You can't use this to send a signal, since each measurement is itself random, but if team A sent classical messages of their results, team B could predict the measurements of B.

        Using further methods like mixing A with C and also B with D before measuring and other stuff, then telling each other what measurements of A&C resulted, it's possible to say that D4 == C4 exactly, 'teleporting' particle C4 (i.e. just reproducing the exact quantum state), but this requires measuring D1, D2, and D3 and thus destroying their state. It's more complicated than this, but resembles a logic puzzle.

  • That's how the can do free shipping on everything!
  • by wisnoskij ( 1206448 ) on Tuesday July 11, 2017 @10:18AM (#54786203) Homepage

    They pointed a flashlight at some satellite.

  • Great. Now I'm going to have to listen to my elderly father go on (again) about how we've invented the Ansible.
  • by Headw1nd ( 829599 ) on Tuesday July 11, 2017 @10:54AM (#54786603)

    Scientists: laypeople are twisting our words and making hyperbolic claims based on their misunderstanding of our research.

    Other Scientists: Hey let's name this phenomenon after a fantastical and thematically similar yet completely unrelated concept in popular culture.

    • The truth is that scientists want people to be intrigued by what they do. They want to accurately explain what they do, but need a hook to get people to listen. IAAS

  • What is the purpose of this experiment running from orbit, or from some greater distance than it had been done before? Was there some speculation that entanglement would no longer manifest due to distance or difference in velocity or within the vacuum of space or something?

  • The Chinese people are on the slope to dominate orbital, and therefore international realtime communications.

    Westerners on Slashdot spend their time bitching about the accuracy of a title of a paper.

    This is how you lose.

  • when they can teleport electrons, protons, and neutrons. Preferably a 200 pound mass of them that happens to be in the shape of a man. Until then, yawn.

  • to the point that we can teleport all politicians up there ... and then quickly destroy the machine before they figure out what we did and try to get back again.

  • It's a copy of data.
    Also, a scifi short story [wikipedia.org].

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