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Science Forum

  1. Standard member blunderdog
    R.I.P. mikelom
    23 Jan '15 18:02
    http://www.msn.com/en-us/news/technology/scientists-slow-the-speed-of-light/ar-AA8uQjo?ocid=ansBBCNews11
  2. 23 Jan '15 18:05
    I read the article this morning. What they are measuring is not really the speed of light in a vacuum. Media are overselling it a bit, as usual. Still, it's a nice experiment.
  3. Standard member blunderdog
    R.I.P. mikelom
    24 Jan '15 02:11 / 1 edit
    But they measured the speed of the photons in a mask, and when they switched it back to a vacuum, the speed remained the same as it was in the mask. That's significant.
  4. 24 Jan '15 10:42
    Originally posted by blunderdog
    But they measured the speed of the photons in a mask, and when they switched it back to a vacuum, the speed remained the same as it was in the mask. That's significant.
    The article was very unclear about what exactly they did. It would be nice to know what the quantum mechanics of this is, but then quantum mechanics never does translate well into macroscopic analogies.
  5. 24 Jan '15 10:47
    Originally posted by twhitehead
    The article was very unclear about what exactly they did. It would be nice to know what the quantum mechanics of this is, but then quantum mechanics never does translate well into macroscopic analogies.
    Basically what they do is some tricks with the geometry to ensure that the light no longer propagates as a plane wave. They then show that this different wave travels at a different speed through a vacuum.
  6. 24 Jan '15 13:51
    Originally posted by KazetNagorra
    Basically what they do is some tricks with the geometry to ensure that the light no longer propagates as a plane wave. They then show that this different wave travels at a different speed through a vacuum.
    Are you able to give us any clue as to why the different wave would travel at a different speed?
    Are plane waves the fastest possible type of waves?
  7. Standard member DeepThought
    Losing the Thread
    24 Jan '15 14:42
    Originally posted by KazetNagorra
    I read the article this morning. What they are measuring is not really the speed of light in a vacuum. Media are overselling it a bit, as usual. Still, it's a nice experiment.
    Is it on ArXiv.org? I tried a couple of search terms but couldn't find it.
  8. 24 Jan '15 17:57
    Originally posted by DeepThought
    Is it on ArXiv.org? I tried a couple of search terms but couldn't find it.
    I read it on Science Express, but there is also an arXiv version:

    http://arxiv.org/abs/1411.3987
  9. Standard member DeepThought
    Losing the Thread
    24 Jan '15 20:06
    Originally posted by KazetNagorra
    I read it on Science Express, but there is also an arXiv version:

    http://arxiv.org/abs/1411.3987
    Many thanks, I think you're right, the media is overselling it - although it is interesting that this can be done with a single photon.
  10. 25 Jan '15 08:06
    To slow down a photon, well, that's one thing.

    But come back when you have sped up a photon to FTL-velocities. That would be really something!
  11. Standard member blunderdog
    R.I.P. mikelom
    27 Jan '15 20:03
    How is being oversold? Just by reporting it? Maybe if they used notations like a chess game, with exclams it would be overselling. Otherwise, it's just straightforward reporting.