Department of Physics, Graduate School of Science
I am studying the unique states of nuclei. Nuclei can be well described by the shell model, in which nuclei are composed of protons and neutrons and all particles have independent orbital motion. On the other hand, there are excited states of nuclei that can only be described by the α-cluster model, in which two protons and two neutrons are strongly bound α-particles as a unit. For example, the Hoyle state of the carbon-12 nucleus is composed of three α-particles and plays a pivotal role in the nucleosynthesis process of the universe. Furthermore, this Hoyle state is called the "α-condensed state" in which all α-particles are Bose-Einstein condensed, suggesting that it is very low density compared to normal nuclei. If the α-condensed state is shown to exist universally in nuclei, it is expected to lead to a better understanding of the physical properties of low-density nuclear matter.