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

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.

Comments: 5 pages, 3 figures