Temperature Dependence of the Low-Momentum Excitations in a Bose Gas of Hard Spheres

The pseudopotential method is used to calculate the temperature dependence of the low-momentum excitations in a Bose gas of hard spheres to an order beyond that previously known. The correction term is shown to be small compared to the leading term for all temperatures less than the critical temperature $T_c$. The excitations become poorly defined for temperatures slightly below $T_c$, however, since it is shown that in this region the excitation lifetimes are quite small.