Condensate depletion
= Condensate depletion
{title2=$n-n_0$}
Occupation outside the macroscopically occupied condensate mode, caused by interactions or thermal excitations. A weak homogeneous three-dimensional Bose gas has zero-temperature depletion fraction $8\sqrt{na_s^3}/(3\sqrt\pi)$ in the leading dilute-gas approximation. Depletion measures single-particle mode occupation, not directly the <superfluid fraction>.