Power-Law Intensity Distribution of γ-Decay Cascades: Nuclear Structure as a Scale-Free Random Network.

By modeling the transition paths of the nuclear $\ensuremath{\gamma}$-decay cascade using a scale-free random network, we uncover a universal power-law distribution of $\ensuremath{\gamma}$-ray intensity ${\ensuremath{\rho}}_{I}(I)\ensuremath{\propto}{I}^{\ensuremath{-}2}$, with $I$ the $\ensuremath{\gamma}$-ray intensity of each transition. This property is consistently observed for all datasets with a sufficient number of $\ensuremath{\gamma}$-ray intensity entries in the National Nuclear Data Center database, regardless of the reaction type or nuclei involved. In addition, we perform numerical simulations that support the model's predictions of level population density.