Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A systematic study of giant quadrupole resonances with the subtracted
  second random--phase approximation: beyond--mean--field centroids and
  fragmentation   A systematic analysis of giant quadrupole resonances is performed for several
nuclei, from $^{30}$Si to $^{208}$Pb, within the subtracted second
random--phase--approximation (SSRPA) model in the framework of the
energy--density--functional theory. Centroid energies and widths of the
isoscalar giant quadrupole resonances are compared with the corresponding
random--phase--approximation (RPA) values. We find lower SSRPA centroid
energies compared to the RPA values leading, in general, to a better agreement
with the experimental data. As far as the widths are concerned, we observe for
both SSRPA and RPA cases a global attenuation of the single--particle Landau
damping going from lighter to heavier nuclei and we obtain, systematically,
larger widths in the SSRPA model compared to the RPA case. For some selected
nuclei for which high--resolution ($p,p'$) experimental data are available,
namely $^{40}$Ca, $^{90}$Zr, $^{120}$Sn, and $^{208}$Pb, the theoretical
strength distributions are directly compared with the experimental spectra. We
observe a significant improvement, with respect to RPA results, in the
description of the spreading widths and of the fragmentation of the obtained
spectra, due to the coupling between 1 particle-1 hole and 2 particle-2 hole
configurations.

31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
24
The categories of this paper are: dg-ga