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posted by janrinok on Saturday February 17 2018, @11:59PM   Printer-friendly
from the like-all-holding-hands dept.

Scientists Create a New Form of Light by Linking Photons

It's a glimpse of science fiction made fact: Scientists have created a new form of light that could someday be used to build light crystals. But before would-be Jedis start demanding their sabers, the advance is far more likely to lead to intriguing new ways of communicating and computing, researchers report this week in Science [DOI: 10.1126/science.aao7293] [DX].

Light is made up of photons—speedy, tiny packets of energy. Typically, photons do not interact with each other at all, which is why when using flashlights "you don't see the light beams bounce off each other, you see them go through each other," explains Sergio Cantu, a Ph.D. candidate in atomic physics at the Massachusetts Institute of Technology. In new experiments, however, the physicists coaxed individual photons to cozy up to each other and link, similar to the way individual atoms stick together in molecules.

[...] [Vaporizing] rubidium with a laser and keeping it ultracold creates a cloud the researchers contain in a small tube and magnetize. This keeps the rubidium atoms diffuse, slow moving and in a highly excited state. Then the team fires a weak laser at the cloud. The laser is so weak that just a handful of photons enter the cloud, a press release from MIT explains. The physicists measure the photons when they exit the other side of the cloud and that is when things get weird.

Normally the photons would be traveling at the speed of light—or almost 300,000 kilometers per second. But after passing through the cloud, the photons creep along 100,000 times slower than normal. Also, instead of exiting the cloud randomly, the photons come through in pairs or triplets. These pairs and triplets also give off a different energy signature, a phase shift, that tells the researchers the photons are interacting.

Also at Newsweek.


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  • (Score: 4, Informative) by maxwell demon on Sunday February 18 2018, @07:50AM (2 children)

    by maxwell demon (1608) on Sunday February 18 2018, @07:50AM (#639651) Journal

    Here's the arXiv version of the actual article: https://arxiv.org/abs/1709.01478 [arxiv.org]

    Looking into this reveals what I already thought: Contrary to what the Smithsonian article suggests, the photons are not bound after they leave; they just preserve the statistics acquired while interacting in the rubidium cloud. The Newsweek article is formulated better in that respect.

    In particular, the following sentence from Smithsonian (also in the summary) is plain wrong:

    But after passing through the cloud, the photons creep along 100,000 times slower than normal.

    Rather, while passing through the cloud, the light is slowed down; afterwards they are back at normal speed.

    --
    The Tao of math: The numbers you can count are not the real numbers.
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  • (Score: 2) by leftover on Sunday February 18 2018, @05:36PM

    by leftover (2448) on Sunday February 18 2018, @05:36PM (#639751)

    Thank you! That makes vastly more sense to me. Like a Bose-Einstein condensate.

    --
    Bent, folded, spindled, and mutilated.
  • (Score: 0) by Anonymous Coward on Monday February 19 2018, @06:26AM

    by Anonymous Coward on Monday February 19 2018, @06:26AM (#639988)

    you would think smithsonian would hire writers with some clue in science.