PauliVerbot

PauliVerbot, sometimes written Pauli-Verbot, is a term encountered in German-language physics writing to denote the prohibition against placing two identical fermions in the same quantum state. It corresponds to what is standardly called the Pauli exclusion principle in English, and Pauli-Ausschlussprinzip in German, but Pauli-Verbot appears mainly in educational or informal contexts rather than formal literature.

In quantum mechanics, fermions such as electrons, protons, neutrons, and quarks obey the spin-statistics connection and are described by antisymmetric many-particle wavefunctions. The antisymmetry implies that exchanging two identical fermions introduces a minus sign, which in turn forbids two fermions from occupying the same single-particle state. In second quantization this is expressed by occupancy numbers n_i ∈ {0,1} and anticommutation relations {c_i, c_j†} = δ_ij.

The PauliVerbot has wide-ranging consequences: it explains the structure of atomic electron shells, the arrangement of elements in chemistry, and the electronic properties of metals and semiconductors. It also underpins degeneracy pressure in dense astrophysical objects, such as white dwarfs and neutron stars, and constrains the possible states in quantum many-body systems.

Because Pauli-Verbot is not a standard term, some readers may confuse it with the formal Pauli exclusion principle. For precise language, it is better to use Pauli exclusion principle or Pauli-Ausschlussprinzip.