The application of quantum mechanics to statistical mechanics
led to almost immediate modification of Drude's theory to a
more apt theory for the many-fermion system.
It is noted that the Fermi-Dirac distribution approaches the
classical Maxwell-Boltzmann distribution at large
temperatures, and the most striking differences between the two
occur in the vicinity of absolute zero.
Room temperature was still low enough for the Sommerfeld model
to achieve better predictions; most improvements were related to
thermodynamical phenomena.