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arXiv · 2502.08901

Bose-Einstein condensation of five $\alpha$ clusters in $^{20}$Ne and supersolidity

S. Ohkubo·J. Takahashi·Y. Yamanaka
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Abstract

We show that the five $\alpha$ cluster states recently observed in $^{20}$Ne, slightly above the five $\alpha$ threshold energy, are Bose-Einstein condensates of five $\alpha$ clusters. The states are described well using a superfluid cluster model, where the order parameter is defined. We suggest that the the five $\alpha$ states are fragmented. Theory predicts the emergence of a five $\alpha$ rotational roton band characterized by a large moment of inertia. This band is formed through roton excitations of the five $\alpha$ BEC vacuum and possesses dual properties of superfluidity and crystallinity, a property of supersolidity. The persistent existence of such a roton bandis discussed and confirmed for the four $\alpha$ condensate above the four $\alpha$ threshold in $^{16}$O and the three $\alpha$ condensate above the three $\alpha$ threshold in $^{12}$C.

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S. Ohkubo, J. Takahashi, Y. Yamanaka. 2025-02-13. Bose-Einstein condensation of five $\alpha$ clusters in $^{20}$Ne and supersolidity. https://doi.org/10.1140/epjp/s13360-025-06049-x

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