Zero-Momentum Condensate Fraction in Ground-State Helium

Estimates are given for the zero-momentum condensate fraction of ground-state ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ described by a Jastrow wave function at the solidification density of the fluid (2%) and at the melting density of the solid (∼1%). Indications are given that these estimates may be sensitively dependent on the form of the pair function utilized.