Fluctuation properties of strength function associated with the giant quadrupole resonance in 208Pb

TL;DR

This study analyzes the fluctuation properties of the strength function for the giant quadrupole resonance in 208Pb, revealing GOE behavior across energy scales, contrasting with 40Ca, due to differences in damping processes.

Contribution

It introduces a fluctuation analysis using local scaling dimensions for the GQR strength function in 208Pb, highlighting GOE behavior and differences from lighter nuclei.

Findings

Strength function fluctuations follow GOE predictions in 208Pb.

Deviation from GOE observed in 40Ca at intermediate energies.

Differences attributed to damping process properties.

Abstract

We performed fluctuation analysis by means of the local scaling dimension for the strength function of the isoscalar (IS) giant quadrupole resonance (GQR) in 208Pb where the strength function is obtained by the shell model calculation including 1p1h and 2p2h configurations. It is found that at almost all energy scales, fluctuation of the strength function obeys the Gaussian orthogonal ensemble (GOE) random matrix theory limit. This is contrasted with the results for the GQR in 40Ca, where at the intermediate energy scale about 1.7 MeV a deviation from the GOE limit was detected. It is found that the physical origin for this different behavior of the local scaling dimension is ascribed to the difference in the properties of the damping process.