What is Pauli exclusion principle?
The '''Pauli exclusion principle''' refers to the fact that certain [[Elementary particles|particles]] cannot be at the same place at the same time, with the same [[energy]]. Only [[fermion]]s (examples are [[proton]]s, [[neutron]]s and [[electron]]s) are bound by the Pauli exclusion principle, while [[boson]]s (an example is a [[photon]] - light beam) are not. A more precise way to describe the Pauli exclusion principle is to say that two of the same kind of fermions that are in the same [[quantum system]] (same atom, for example) cannot have the same [[quantum number]]s. This principle was discovered by [[physicist]] [[Wolfgang Pauli]] in 1925. It is a very important principle in [[physics]] because the particles that make up ordinary matter are fermions. {{physics-stub}} [[Category:Quantum mechanics]]