PlanetPhysics/Pauli Exclusion Principle

The Pauli exclusion principle states that fermions are antisymmetric under particle exchange, and that as a consequence no two fermions may occupy the same quantum state. Mathematically, the exchange operator for a two-body wavefunction is

Normalisation considerations tell us that the eigenvalue, must be either (as the operator must conserve probability). The Pauli exclusion principle then states that the eigenvalue is for bosons and for fermions, and that a wavefunction with an eigenvalue of describes particles that cannot occupy the same quantum state. The spin-statistics theorem states that these particles are fermions, with half-integer spin.