< **1** >

### Fermi-Dirac statistics

The Fermi-Dirac statistics is a method from quantum physics that describes the expected number of fermions that have a certain energy.

##### Explanation

It applies to identical particles with half-integer spin in a system with thermodynamic equilibrium. Additionally, the particles in this system are assumed to have negligible mutual interaction. The number of particles *n* in the state *i* can then be calculated with

where

g_{i}Degeneracy ε_{i}Energy of the state µChemical potential k_{B}Boltzmann constant TTemperature

The Pauli exclusion principle states that two or more identical fermions cannot simultaneously occupy the same quantum state within a quantum system. This applies, for example, to the electrons that provide electrical conduction in metals and semiconductors

##### Additional information

It is named after Enrico Fermi and Paul Dirac, each of whom discovered the method independently in 1926.