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HK: Fachverband Physik der Hadronen und Kerne
HK 14: Structure and Dynamics of Nuclei V
HK 14.2: Talk
Tuesday, March 11, 2025, 14:30–14:45, HS 2 Physik
Many-body emulators for nuclear structure — •Margarida Companys Franzke1,2,3, Kai Hebeler1,2,3, Takayuki Miyagi4,1,2,3, Alexander Tichai1,2,3, and Achim Schwenk1,2,3 — 1Technische Universität Darmstadt, Department of Physics — 2ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH — 3Max-Planck Institut für Kernphysik, Heidelberg — 4Center for Computational Sciences, University of Tsukuba
Emulation techniques have become a popular tool in nuclear physics to study Hamiltonians with an explicit parametric dependence. An important example is given by two- and three-nucleon interactions derived from chiral effective field theory that depend linearly on low-energy couplings (LECs). Eigenvector-continuation-based emulators allow for the sampling of millions of nuclear interaction models, which is needed, e.g., for large-scale sensitivity studies, lowering the computational cost significantly with respect to explicit many-body simulations. In this work, we construct an emulator from a set of Hartree-Fock training states to study the impact of variations of three-body couplings on the N=32 shell closure in calcium isotopes. The experimentally measured difference in charge radii of 52Ca compared to 48Ca is underpredicted in ab initio calculations and still poses a major challenge to nuclear theory. As an outcome of this work we identify domains in LECs space that can give predictions compatible with the experiments and help construct the next generation of chiral Hamiltonians.
*Funded by the ERC Grant Agreement No. 101020842
Keywords: Eigenvector continuation; Hatree-Fock method; Chiral EFT; Calcium charge radii