A statistical description of a system of particles that obeys the rules of quantum mechanics rather than classical mechanics. In quantum statistics, energy states are considered to be quantized. If the particles are treated as indistinguishable, Bose-Einstein statistics apply if any number of particles can occupy a given quantum state. Such particles are called bosons. All known bosons have an angular momentum nh, where n is zero or an integer and h is the Planck constant. For identical bosons the wave function is always symmetric. If only one particle may occupy each quantum state, Fermi-Dirac statistics apply and the particles are called fermions. All known fermions have a total angular momentum (n+½)h/2π and any wave function that involves identical fermions is always antisymmetric.
Subjects: Physics — Chemistry.