Antisymmetrized molecular dynamics (AMD), developed in the 1990s, provides a unified framework for describing nuclear structures and reactions. It models nucleons as independent Gaussian wave packets, enabling the description of nucleon aggregation and disaggregation dynamics. AMD has significantly advanced the understanding of nuclear fragmentation reactions at medium-to-high energies and cluster structures in light nuclei. However, its reliance on the Gaussian-type single-nucleon wave function limits its application to low-energy nuclear reactions and the structural description of heavier nuclei, where deviations from Gaussian density distributions become significant.

This study introduces a novel model wave function to address these limitations. The single-nucleon wave function was expressed as a superposition of localized Gaussian functions, with the superposition amplitudes and the Gaussian centers (mean positions and momenta of wave packets) serving as model parameters. This formulation enabled a more adaptable representation of nucleon wave functions. Equations of motion were derived for the superposition amplitudes and Gaussian centers by applying the variational principle. The former corresponds to the standard Hartree-Fock equation, while the latter extends the AMD equation, unifying the two approaches within a single framework. Benchmark calculations for spherical nuclei, such as calcium isotopes and ¹⁰⁰Sn, are presented, demonstrating significant improvements over conventional AMD methods (Figure 1).

Future developments include incorporating pairing correlations, angular momentum projections, and generator coordinate methods to enhance nuclear structure descriptions. Additionally, extending this approach to real-time calculations will facilitate the modeling of low-energy nuclear reactions with higher precision.

(Written by M. Kimura on behalf of all the authors)

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