https://doi.org/10.1140/epja/s10050-024-01231-8
Regular Article - Theoretical Physics
Multiconfigurational time-dependent density functional theory for atomic nuclei: technical and numerical aspects
1
Centre Borelli, ENS Paris-Saclay, Université Paris-Saclay, 91190, Gif-sur-Yvette, France
2
CEA, DAM, DIF, 91297, Arpajon, France
3
Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680, Bruyères-le-Châtel, France
4
Université Paris-Saclay, CNRS/IN2P3, IJCLab, 91405, Orsay, France
Received:
31
October
2023
Accepted:
25
December
2023
Published online:
22
January
2024
The nuclear time-dependent density functional theory (TDDFT) is a tool of choice for describing various dynamical phenomena in atomic nuclei. In a recent study, we reported an extension of the framework – the multiconfigurational TDDFT (MC-TDDFT) model – that takes into account quantum fluctuations in the collective space by mixing several TDDFT trajectories. In this article, we focus on technical and numerical aspects of the model. We outline the properties of the time-dependent variational principle that is employed to obtain the equation of motion for the mixing function. Furthermore, we discuss evaluation of various ingredients of the equation of motion, including the Hamiltonian kernel, norm kernel, and kernels with explicit time derivatives. We detail the numerical methods for resolving the equation of motion and outline the major assumptions underpinning the model. A technical discussion is supplemented with numerical examples that consider collective quadrupole vibrations in 
Ca, particularly focusing on the issues of convergence, treatment of linearly dependent bases, energy conservation, and prescriptions for the density-dependent part of an interaction.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
