Bubble Ar and its new breathing modes
Ge Ren (Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China, College of Physics, Henan Normal University, Xinxiang, China)
; Chun-Wang Ma (Shanghai Research Center for Theoretical Nuclear Physics, NSFC, Fudan University, Shanghai, China, College of Physics, Henan Normal University, Xinxiang, China, Institute of Nuclear Science and Technology, Henan Academy of Sciences, Zhengzhou, China)
; Xi-Guang Cao (Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai, China)
; Yu-Gang Ma (Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, Shanghai, China, Shanghai Research Center for Theoretical Nuclear Physics, NSFC, Fudan University, Shanghai, China)
The bubble nuclei are important components of exotic nuclear structures characterized by special depletions of central densities. Focusing on bubble structures of $^{36}$Ar, the characterizations of bubble nuclei were explored with the framework of the extended quantum molecular dynamics model. Three density distribution modes were uncovered for the first time, i.e. micro-bubble, bubble, and cluster resonances, which show unique spectral signature compared to the monopole resonance spectrum as the excitation intensity was increased in bubbles. Of pivotal importance is the revelation that the bubble mode's oscillation frequency closely resembles macroscopic bubble dynamics, building a connection between classical macroscopic phenomena and the quantum complexity of the nuclear structure. The discovery marks a crucial step forward in deciphering the relationship between classical and quantum domains within the enigmatic world of atomic nuclei.