Momentum Distribution in Liquid 4He at Low Temperatures: Variational Methods

摘要: We review variational calculations of the momentum distribution and condensate fraction atoms in liquid 4 He at zero low temperatures. use ground state excited wave functions which include Jastrow, three-body backflow correlations are obtained from that give accurate energies pair over a wide density range. calculate change due to creation an elementary excitation it temperatures (T < 1°K). This calculation brings out collective single-particle character excitations long short wavelength limit respectively interplay between two intermediate momenta. The expectation values calculated by means cluster expansions making hypernetted-chain equation scaling approximation contribution diagrams. discuss singularities momenta compare our results with distributions Green’s function Monte Carlo neutron scattering data.