I remember I read somewhere about the boltzmann distribution that it

[aaaa202]

I remember I read somewhere about the Boltzmann distribution that it is only valid for high temperatures. Why is that?

 

[DrewD]

At very low temperatures quantum effects start to make a significant contribution the distribution and Bose-Einstein or Fermi-Dirac statistics take over depending on whether the particles are fermions or bosons. At high temperatures the kinetic energy of particles drowns out the effects of quantum mechanics.
http://en.wikipedia.org/wiki/Fermi–Dirac_statistics
http://en.wikipedia.org/wiki/Bose–Einstein_statistics