Beyond-mean-field corrections within the second random-phase approximation

21st International School on Nuclear Physics and Applications & International Symposium on Exotic Nuclei

Grasso, M.^1 ; Gambacurta, D.^2 ; Engel, J.^3

Institut de Physique Nuclèaire, IN2P3-CNRS, UniversitèParis-Sud, Orsay Cedex

F-91406, France^1

Extreme Light Infrastructure - Nuclear Physics (ELI-NP), Horia Hulubei National Institute for Physics and Nuclear Engineering, 30 Reactorului Street, Magurele, Jud. Ilfov

RO-077125, Romania^2

Department of Physics and Astronomy, University of North Carolina, North Carolina 27516-3255, Chapel Hill, United States^3

关键词: Double counting;    Effective interactions;    Energy density;    Excitation spectrum;    Hole configuration;    Random phase approximations;    Stability condition;    Subtraction procedure;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/724/1/012018/pdf
DOI  :  10.1088/1742-6596/724/1/012018

来源: IOP

【 摘 要 】

A subtraction procedure, introduced to overcome double-counting problems in beyond-mean-field theories, is used in the second random-phase approximation (SRPA). Doublecounting problems arise in the energy-density functional framework in all cases where effective interactions tailored at leading order are used for higher-order calculations, such as those done in the SRPA model. It was recently shown that this subtraction procedure also guarantees that the stability condition related to the Thouless theorem is verified in extended RPA models. We discuss applications of the subtraction procedure, introduced within the SRPA model, to the nucleus16O. The application of the subtraction procedure leads to: (i) stable results that are weakly cutoff dependent; (ii) a considerable upwards correction of the SRPA spectra (which were systematically shifted downwards by several MeV with respect to RPA spectra, in all previous calculations). With this important implementation of the model, many applications may be foreseen to analyze the genuine impact of 2 particle-2 hole configurations (without any cutoff dependences and anomalous shifts) on the excitation spectra of medium-mass and heavy nuclei.