Saturation and Condensate Fraction Reduction of Cold Alpha Matter

The ground state energy of ideal alpha-matter at T=0 is analyzed within the framework of variational theory of Bose quantum liquids. Calculations are done for three local alpha-alpha potentials with positive volume integrals and two-body correlation functions obtained from the Pandharipande-Bethe equation. The energy per particle of $\alp$ matter is evaluated in the cluster expansion formalism up to four-body diagrams, and using the HNC/0 and HNC/4 approximation for a Bose liquid. Inclusion of higher order terms in the cluster expansion of the condensate fraction are leading to a stronger depletion of the alpha condensate with the density compared to the two-body approximation prediction.