Fig. 1: Diagrammatic representation for the shell-model-like ground state and the possible 5α condensate state in 20Ne.
The ground state of 20Ne, with the saturated density ρ0, has a liquid compact structure and it can be described by the standard shell-model picture, in which the nucleons are assumed to move in a single-particle mean field and occupy different orbits. With the increase of excitation energy, the liquid-like ground state can be evolved to various clustering structures. Around the 5α threshold (Ex = 19.2 MeV) and the low density e.g., ρ0/5, the 5α clustering structure is expected to form BEC condensate state, in which the 5α clusters mainly move with (0S) orbit in a cluster-type mean field.
