2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/24544The standard calculations of the ground-state energy of a homogeneous Bose gas rely on approximations which are physically reasonable but difficult to control. Lieb and Yngvason [Phys. Rev. Lett. 80, 2504 (1998)] have proved rigorously that the commonly accepted leading order term of the ground state energy is correct in the zero-density-limit. Here, strong indications are given that also the next to leading term is correct. It is shown that the first terms obtained in a perturbative treatment provide contributions which are lost in the Bogoliubov approach.6 pages, accepted for publication in Europhys. Lett. http://www.epletters.ch/Statistical Mechanicstext