Bose-Einstein distribution law

The Bose-Einstein distribution law was derived by S.N. Bose in 1924 to describe a photon gas. Einstein extended it to material gasses. Fermi developed the Fermi-Dirac distribution law in 1926 by exploring the Pauli exclusion principle, and Dirac obtained it independently in the same year by considering antisymmetric wavefimctions. 

A simple example of this, which makes clear the mathematical mechanism by which it occurs, is seen in the ideal Bose gas, which provides an exactly soluble model of a critical point. The number of single-pardde states with energy in the range e to e +de is proportional to de in d dimensions, while the occupancy of a state of energy e is exp[(e -ft)/kTl-1 ", with 0, by the Bose-Einstein distribution law so the density of the gas at given p, and T is expressible in terms of the integral... 

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