The 5α condensate state in <sup>20</sup>Ne.

Zhou, Bo; Funaki, Yasuro; Horiuchi, Hisashi; Ma, Yu-Gang; Röpke, Gerd; Schuck, Peter; Tohsaki, Akihiro; Yamada, Taiichi · Nat Commun · 2023

basic_science · Level V

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Abstract

The formed <sup>4</sup>He (α) clusters consisting of two neutrons and two protons can be a building block in light nuclear systems. Intriguingly, these alpha clusters could potentially form alpha condensate states within the nuclear system. The Hoyle state at 7.65 MeV in <sup>12</sup>C, which plays an essential role in stellar nucleosynthesis, is now considered to be a phase transition, namely the 3α Bose-Einstein condensate. Confirming the existence of Hoyle-analog states in Nα nuclei (N > 3) remains a major challenge. Here we show microscopic five-body calculations for the <sup>20</sup>Ne nucleus. We find that one excited 0<sup>+</sup> state has a distinct gas-like characteristic and represents the condensate state. Identifying the 5α condensate state is an important step in establishing the concept of α condensation in nuclear fermion systems.