Speaker
Description
The generator coordinate method (GCM) has been a well-known method to describe nuclear collective motions [1]. 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 assumption. With such choice, it is not trivial whether the collective motion of interest can be optimally described (See e.g., [2-3]). 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 contribution, we present a new extension of GCM in which both the basis SDs and the weight functions are optimized according to the variational principle [4]. 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 presentation, we will show results for sd- shell nuclei with the Skyrme energy functional. We will show that the optimized bases correspond to excited states along a collective path, unlike the conventional GCM which superposes only the local ground states. This implies that a collective coordinate for large amplitude collective motions is determined in a much more complex way than what has been assumed so far.
[1] P. Ring and P. Schuck, The Nuclear Many-Body Problem (Springer, 1980).
[2] N. Hizawa, K. Hagino and K. Yoshida, Phys. Rev. C 103, 034313 (2021).
[3] N. Hizawa, K. Hagino and K. Yoshida, Phys. Rev. C 105, 064302 (2022).
[4] M. Matsumoto, Y. Tanimura and K. Hagino, Phys. Rev. C 108, L051302 (2023).
| Type of contribution | |
|---|---|
| Are you a student or postdoc? | yes |
