Feasibility of the finite amplitude method in covariant density functional theory

TL;DR

This paper demonstrates the feasibility of using the finite amplitude method within covariant density functional theory to efficiently perform relativistic RPA calculations, accurately accounting for Dirac sea effects and density-dependent interactions.

Contribution

It introduces the application of the finite amplitude method to covariant density functional theory for relativistic RPA, enabling automatic inclusion of Dirac sea effects and efficient computation of rearrangement terms.

Findings

FAM successfully applied to covariant density functional theory.

Relativistic RPA calculations verified against conventional methods.

Automatic inclusion of Dirac sea effects and density-dependent terms.

Abstract

Self-consistent relativistic random-phase approximation (RPA) in the radial coordinate representation is established by using the finite amplitude method (FAM). Taking the isoscalar giant monopole resonance in spherical nuclei as example, the feasibility of the FAM for the covariant density functionals is demonstrated, and the newly developed methods are verified by the conventional RPA calculations. In the present relativistic RPA calculations, the effects of the Dirac sea can be automatically taken into account in the coordinate-space representation. The rearrangement terms due to the density-dependent couplings can be implicitly calculated without extra computational costs in both iterative and matrix FAM schemes.