Definition

1. Noun:
   • A fundamental principle in quantum mechanics: The Pauli exclusion principle states that no two identical fermions (particles with half-integer spin, such as electrons, protons, or neutrons) within a given quantum system can occupy the same quantum state simultaneously. This means they cannot have an identical set of all four quantum numbers (principal, azimuthal, magnetic, and spin).

Usage Examples

• Noun:
  • The stability of matter and the structure of the periodic table are direct consequences of the Pauli exclusion principle.
  • According to the Pauli exclusion principle, two electrons in the same orbital must have opposite spins.
  • The Pauli exclusion principle is crucial for understanding white dwarf stars and neutron stars.

Advanced Usage

• "to be governed by the Pauli exclusion principle": to have its behavior or structure determined by this rule.
  • The electron configuration in an atom is strictly governed by the Pauli exclusion principle.

Variants and Related Words

• Exclusion principle (n): A common shortened form referring to the Pauli exclusion principle.

  • The exclusion principle prevents matter from collapsing into a very dense state.

• Pauli principle (n): Another common abbreviated name for the Pauli exclusion principle.

  • The Pauli principle is a key concept in quantum statistics.

Synonyms

• Quantum exclusion principle: A descriptive synonym emphasizing its origin in quantum theory.

Related Phrases

• To violate the Pauli exclusion principle: An impossible scenario under standard quantum mechanics, often used in hypothetical discussions.
  • If a system were to violate the Pauli exclusion principle, its fundamental properties would be completely different.

Related Concepts (Not Idioms)

• Fermi-Dirac statistics: The statistical mechanics that describe systems of particles obeying the Pauli exclusion principle.
• Spin-statistics theorem: A more fundamental theorem in quantum field theory from which the Pauli exclusion principle for fermions is derived.

Noun

1. no two electrons or protons or neutrons in a given system can be in states characterized by the same set of quantum numbers