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Résumé |
The generator coordinate method (GCM) has been a well-known method to describe nuclear
collective motions. In GCM, one a priori specifies collective degrees of freedom (collective
coordinates), such as nuclear deformations, and superposes many Slater determinants (SDs)
within the selected collective subspace. However, there always exists arbitrariness in this
approach in the choice of collective coordinates, for which one has to rely on empirical and
phenomenological theory. With such choice, it is not trivial whether the collective motion of
interest can be optimally described (See e.g., [1]). Therefore, a description of the collective
motion without pre-set collective coordinates is desirable in order not to miss important
degrees of freedom. In this seminar, we present a new extension of GCM in which both the
basis SDs and the weight functions are optimized according to the variational principle [3].
With such simultaneous optimization of the basis states, one does not have to specify
beforehand the relevant collective degrees of freedom covered by the set of basis SDs. In this
talk, we will show results for sd-shell nuclei with the Skyrme energy functional. We will
show that some collective coordinates often assumed in conventional GCM calculations,
such as quadrupole moment, may not provide optimum basis to describe the ground state.
This would be an important step towards consistent description of nuclear collective
motions.
[1] N. Hizawa, K. Hagino and K. Yoshida, Phys. Rev. C 103, 034313 (2021).
[2] N. Hizawa, K. Hagino and K. Yoshida, Phys. Rev. C 105, 064302 (2022).
[3] N. Shimizu et al., Prog. Theor. Exp. Phys. 2012, 01A205 (2012). |
