Any term of the form e-
/τ is called a Boltzmann
Factor.
Any term of the form e(Nμ-)/τ is called a Gibbs factor.
The Gibbs Sum is the sum of all of the Gibbs Factors for the states and numbers of a system, and is given by:
e(Nμ-
)/τ
The Partition Function represents the sum of all of the Boltzmann Factors for the states of a system, and is given by:
e-
/τ
The Planck distribution function describes the average number of photons < s > in a particular frequency σ for blackbody radiation and is given by:
The Stefan-Boltzmann law of radiation gives the energy density of radiation in a cavity, as can be expressed:
= 
τ4
The probability of finding a system in energy state  if the system is in thermal contact with a reservoir
|
P(
 ) =  |
| The entropy of blackbody radiation |
σ =
 ( )3
|
