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Quantum Entanglement of Macroscopic Diamonds

Posted by Soulskill on from the simultaneously-a-girl's-best-friend-and-not dept.

New submitter ananyo writes "A pair of diamond crystals has been linked by quantum entanglement — one of the first times that objects visible to the naked eye have been placed in a connected quantum state. 'This means that a vibration in the crystals could not be meaningfully assigned to one or other of them: both crystals were simultaneously vibrating and not vibrating (abstract). Quantum entanglement — interdependence of quantum states between particles not in physical contact — has been well established between quantum particles such as atoms at ultra-cold temperatures. But like most quantum effects, it doesn't tend to survive either at room temperature or in objects large enough to see with the naked eye.'"

15 of 160 comments (clear)

  1. weird. by notgm · · Score: 5, Funny

    this both gives me the chills, and doesn't.

  2. www.quantum-vibrator.xxx by Slugster · · Score: 5, Funny

    great..... we dump all this money in some eggheads' laps, and all they can think of is to make fancy adult toys

  3. Quantum First Post! by Dutchmaan · · Score: 4, Funny

    This is a first post, and yet it isn't!

  4. next step in this study by niw3 · · Score: 4, Funny

    should be an experiment with a cat & some poison

  5. 0.05 mm by .25 mm by Anonymous Coward · · Score: 4, Informative

    They say that each phonon involves the coherent vibration of about 1016 atoms, corresponding to a region of the crystal about 0.05 millimetres wide and 0.25 millimetres long â" large enough to see with the naked eye.

    0.05 mm is roughly 1/4 the width of a human hair. Of course, I still can't see it, because it's just a patch of vibrations on a much larger diamond.

  6. Harmony at last.. by RenHoek · · Score: 4, Funny

    Neat... Now I can get a pair of diamond vibrators and please both my wife and mistress at the same time!

    1. Re:Harmony at last.. by roc97007 · · Score: 3, Funny

      Or not, at the same time.

      --
      Oliver's law of assumed responsibility: If you're seen fixing it, you will be blamed for breaking it.
    2. Re:Harmony at last.. by Baloroth · · Score: 5, Informative

      Actually, no, because they are quantum entangled only one of them can vibrate at a time. So you can still only please one at at a time, you just don't know which one it will be until they tell you.

      --
      "None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
    3. Re:Harmony at last.. by Baloroth · · Score: 4, Informative

      No. The experiment took one photon, and sent it along two possible paths without recording which path it took, which causes a vibration in one (and only one) diamond. Since the path of the photon was random, and not recorded, you cannot say which diamond is vibrating. The way the researchers put it (better than the summary IMO) is "Neither the statement 'this diamond is vibrating' nor 'this diamond is not vibrating' is true.” You cannot selectively vibrate one. In fact knowing which one vibrates destroys the entanglement. It does, however, tell you the state of the other diamond (the opposite) without observing it directly, which creates a few paradoxes and is the source of the whole 'spooky action thing.'

      Don't feel to bad if you don't understand it, even quantum physicists don't understand quantum physics very well. The mechanics behind what is really happening in entanglement is still unknown, there is only guesswork as to how it might happen.

      --
      "None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
  7. Someone correct me if I'm wrong but... by Shadow+of+Eternity · · Score: 4, Interesting

    As near as I can understand this they're entangled so that vibrations in one are indistinguishable from vibrations in another, they both do the same thing at the same time (or near it at least)... doesn't this imply the ability to entangle two whatevers and transit information via entanglement induced vibrations?

    --
    A bullet may have your name on it but splash damage is addressed "To whom it may concern."
    1. Re:Someone correct me if I'm wrong but... by Baloroth · · Score: 4, Informative

      No, since when you establish the vibrations you don't know in which one it occurs. So while you could establish vibrations in a distant diamond (or particle), at least theoretically, you never know when you do so which one is actually vibrating. When they set it up, they used 1 photon that could travel and strike either diamond, creating the vibrations. Without measuring the photon's path, they didn't know which one it hit and therefore which on would be vibrating. This caused the entanglement.

      Two things: 1), the photon itself had to be able to strike both (so not FTL at all for this setup) and 2) no useful information was encoded in this experiment. One thing you could do, though, would be send one diamond one direction and the other another way. Either can know the other diamond's state by reading his own (the other is in the opposite), and no one else can, since anyone else reading it would collapse the state, and a second reading would have a different result (I believe this is more or less how quantum cryptography works). Quantum entanglement is useful for transferring information (in other cases), but the mechanics still don't allow FTL information transfer, they just allow you to encode more in less space by having two bits quantum entangled. I don't completely understand the physics of that.

      --
      "None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
    2. Re:Someone correct me if I'm wrong but... by LateArthurDent · · Score: 3, Insightful

      As near as I can understand this they're entangled so that vibrations in one are indistinguishable from vibrations in another, they both do the same thing at the same time (or near it at least)... doesn't this imply the ability to entangle two whatevers and transit information via entanglement induced vibrations?

      No, they are in opposite states. If you measure one of them, you'll determine that it is either vibrating or not. If it is vibrating, the other diamond is not, if it's not vibrating, the other diamond is vibrating. Before the measurement, they're entangled, so they are considered to be both vibrating and not vibrating simultaneously.

      That said, I don't know much about quantum effects, so I can't read the paper and understand it, but the description in the article made it seem like what's actually happening is just that the experiment is set up such that only one diamond can be vibrating, but you don't know which one it's going to be. So at all times, one of the diamonds is vibrating, the other is not, and you only know which is which when you measure one of them. Which doesn't sound like anything special. It's like me getting two playing cards, an Ace and a King, and putting them in a table face down. Then I ask you, "which one is the card in the left?" and you answer, "it's both a King and Ace. Until I flip it over, and then I can tell you what the other one is." Which is ridiculous, the card is one card specifically, you just don't know which one it is. So I suspect the media writeup screwed up, although it still seems way better than most, since they didn't mention stuff like ftl communications which pops up in almost every entanglement story even though we all know entanglement can't enable ftl communication.

  8. Re:Is this again just a theory? by Taibhsear · · Score: 4, Informative

    Did you actually read the article? "Cheap words" make up all science and literature. They explained everything they did in the article. Or do you expect them to post all their experimental data on this brief web article?

    "When we detect the Stokes photon we know we have created a phonon, but we can't know even in principle in which diamond it now resides," says Walmsley. "This is the entangled state, for which neither the statement 'this diamond is vibrating' nor 'this diamond is not vibrating' is true."

    To verify that the state has been made, the researchers fire a second laser pulse into the two crystals to 'read out' the phonon, from which the laser photon draws extra energy.

  9. Re:FTL Communications by nomel · · Score: 3, Informative

    Unfortunately, this is not the implementation of the universe.

    Here are some answers to the question, Does quantum entanglement allow faster-than-light information transfer?, given by scientists.

  10. Statistics not particles by dak664 · · Score: 4, Interesting

    Let us not lose sight of the fact that a photon is a statistical convenience, not a particle, and a phonon is even less a particle. You can't send "one photon" and detect "one phonon". These are statistical coincidence measurements that detect correlated behavior between the two diamonds after an electromagnetic interaction that can not transfer less than Planck's constant of action. Either diamond would show a 50% excitation in the absence of the signal from the other. Spooky action at a distance is inferred from correlation of the states over a large number of events. Which is why quantum computing is not going to be as fast as everyone thinks it will be.