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I Quantum entangled image sensor for space camera-telescope

  1. Jul 25, 2017 #1
    Could this be a possibility at some point? Since entanglement is not affected by distance, could we send cameras out to extremely distant places and get instantaneous signals? Only the image sensor would have to be entangled. It would still take the same amount of time as usual to get the camera to its destination, but once there, we would be able to see things as they are, not as they were. It seems to me this would be incredibly valuable. I'm a layman, not a physicist, but I don't see why this couldn't be done, maybe even within the next 50 years, if the technology advances the way it's been going. But I'm curious to hear what more knowledgeable folks than myself have to say about it. I've never heard the idea come up, though it's hard to imagine I'm the first to think of it.
  2. jcsd
  3. Jul 25, 2017 #2


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    Entanglement is not affected by distance, true. But what signal would you expect to see?

    Entangled particle properties have no predetermined values. When you measure one, you get a random value. The other one will exhibit a matching random value. But random outcomes don't leave room for gaining information about a remote system.
  4. Jul 25, 2017 #3


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    As DrChinese said, it doesn't work and this is one of the first things you learn in Quantum Mechanics. Still, it is one of the most prevalent but utterly bogus "scientific" statements that you will find to be widespread in bad pop-sci presentations (and they are almost all bad). I even saw it in Time magazine last week.

  5. Jul 25, 2017 #4
    So it sounds like what you are saying is that the idea of an image sensor composed of quantum-entangled particles is flawed. My thought was that the image sensor in the space-camera could respond to light or other electromagnetic radiation to produce an image (or data that could be reconstructed into an image) and that would be reflected in its counterpart on earth, in the lab. I was under the impression that changes could be affected in quantum particles that are not random. If they are always random, and cannot be controlled, why is quantum computing even a consideration? I guess I understand this even less than I thought... I'm sorry if I'm wasting your time.
  6. Jul 25, 2017 #5
    Hey... no statements or assertions made there... just a question. I don't presume that I know what I'm talking about.
  7. Jul 25, 2017 #6


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    They are random, but they are also correlated. For a simple classical example (which unfortunately does not capture one of the most fascinating things about quantum entanglement - google for "Bell's Theorem" for details), suppose that a coin is tossed 100 times, and I record the results, writing down an "H" every time it comes up heads and a "T" every time it comes up tails. I'll end up with a completely random sequence of those letters. Now if you were to to present me with another random string of those letters and we compared them and found that everywhere I had an H you had a T and vice versa, we would quickly conclude that we must have been looking at opposite faces of the same coin.

    Clearly we can't send signals this way, but that doesn't mean that the result is not interesting and important. The fact that we're dealing with the same underlying quantum system is itself interesting, and doesn't emerge until we compare the two random strings for correlations. And there are practical applications in which it doesn't matter that the data is random as long as we both have it; perhaps the most important, and the reason that these long-distance entanglement setups are getting so much attention, is the exchange of encryption keys - google for "quantum key distribution" for more.
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