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Cooling by Heating

Discussion in 'Science & Technology' started by micropage7, Jan 24, 2012.

  1. micropage7

    micropage7

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    Don’t worry if you find this
    confusing, it somewhat is.
    Researchers at the University of Copenhagen have successfully cooled a semiconductor
    membrane down to -269 C, or
    4.15 K. This was accomplished by
    heating the material with a laser.
    Yes, the researchers heated the
    material to cool it. The membrane, a 1 mm x 1 mm x
    160 nm piece of gallium arsenide
    (GaAs) was placed in a vacuum
    chamber and had a laser aimed
    at it. The membrane partially
    absorbed and partially reflected the light. The reflected light
    struck a mirror and was bounced
    back to the membrane, creating
    an optical resonator. When the
    light is absorbed by the
    membrane, electrons within it get excited and move around
    some. When these electrons fall
    they release energy as heat,
    which causes the membrane to
    expand and contract. These
    fluctuations cause the distance between the membrane and the
    mirror to change. Though the
    fluctuations are small, they are
    enough to cause some
    interesting interactions. One of
    the resulting interactions is for the fluctuations themselves to
    cool. Even though the
    membrane, in general, is
    warming, there are specific
    oscillations of the fluctuations
    that cause it to cool down to near absolute zero.
    www.overclockersclub.com/news/30508/
     
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  2. qubit

    qubit Overclocked quantum bit

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    Weird effect. Don't you just love physics at this level? :)
     
  3. KainXS

    KainXS

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    beautiful isn't it
     
  4. Drone

    Drone

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