Evidence of alpha particle condensation in $^{12}$C and $^{16}$O and Nambu-Goldstone boson

TL;DR

The paper proposes that the 0+ states in carbon-12 and oxygen-16 are evidence of alpha particle Bose-Einstein condensation, identified through the observation of a Nambu-Goldstone boson, indicating a phase mode of the condensate.

Contribution

It introduces a novel interpretation of specific nuclear states as Nambu-Goldstone bosons signaling alpha particle condensation in nuclei.

Findings

Identification of the 0+ states as Nambu-Goldstone bosons

Large moment of inertia of the rotational band

Evidence supporting alpha particle Bose-Einstein condensation

Abstract

It is suggested that direct evidence of Bose-Einstein condensation of alpha particles is obtained by observing a phase mode (Nambu-Goldstone boson) with long wavelength even when characteristic features such as superfluidity is diffucult to observe. For the 7.65 MeV $0_2^+$ Hoyle state in $^{12}$C and 15.1 MeV $0^+$ state in $^{16}$O, which are candidates for an alpha particle condensate, it is suggested that the emergent band head $0^+$ state of the $K=0_2^+$ rotational band with a very large moment of inertia is considered to be a Nambu-Goldstone boson.