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Mean thermal wavelenght

  1. Dec 24, 2007 #1
    hi
    i want to calculate "mean thermal wavelenght for relativistic particles"for example for photon .
    i dont khow how can i do it.
    please help me.
    thankyou.
     
  2. jcsd
  3. Dec 24, 2007 #2

    Gokul43201

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    There are different (final) equations for massless particles than for massive particles. For massless particles, you use,
    [tex]\lambda = \frac{hc}{\pi^{1/3} 2kT}[/tex]
    and for massive particles, you use the thermal de Broglie wavelength. In general, you can extract a thermal wavelength out of the dispersion relation for the particle.
     
  4. Dec 25, 2007 #3
    thankyou for your answer
    i know this relation for phonon,but can you send for me relations ,that give this equetion .
    in fact ,i dont khow how can i obtain this equation
    thankyou
     
  5. Dec 25, 2007 #4

    Gokul43201

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    One answer is that it is simply defined this way, and needs no derivation, but that would not be an accurate statement. In fact, there is a paper that proposes a generalized equation for the thermal wavelength for all particles (living in n-dimensional space) with a power law dispersion relation.

    Z. Yan, "General thermal wavelength and its applications", Eur. J. Phys. 21 (2000) 625
     
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