 William I. McAlexander

An experimental researcher whose team observed degeneracy pressure in a trapped gas of atoms obeying Fermi-Dirac statistics. Cooling a fermionic cloud alongside a bosonic one lets their sizes be compared under common experimental conditions. The fermionic distribution resists the concentration expected for a classical gas because the Pauli exclusion principle prevents identical fermions from all occupying the same low-energy state. The cloud’s spatial profile therefore makes a consequence of quantum statistics directly measurable.^[ref]