# Ab Initio Symmetry-Adapted Emulator for Studying Emergent Collectivity and Clustering in Nuclei

## TL;DR

This paper introduces a novel symmetry-adapted emulator based on eigenvector continuation and symplectic symmetry, enabling efficient study of nuclear clustering and collective properties without effective charges.

## Contribution

It presents a new emulator framework utilizing symplectic symmetry and eigenvector continuation, improving predictions of nuclear features and aiding in constraining nuclear forces.

## Key findings

- Emulators accurately predict excitation energies and radii for 6Li and 12C.
- Predictions are robust against variations in chiral potential parameters.
- Emulators effectively capture nuclear shape, clustering, and collective behaviors.

## Abstract

We discuss emulators from the ab initio symmetry-adapted no-core shell-model framework for studying the formation of alpha clustering and collective properties without effective charges. We present a new type of an emulator, one that utilizes the eigenvector continuation technique but is based on the use of symplectic symmetry considerations. This is achieved by using physically relevant degrees of freedom, namely, the symmetry-adapted basis, which exploits the almost perfect symplectic symmetry in nuclei. Specifically, we study excitation energies, point-proton root-mean-square radii, along with electric quadrupole moments and transitions for 6Li and 12C. We show that the set of parameterizations of the chiral potential used to train the emulators has no significant effect on predictions of dominant nuclear features, such as shape and the associated symplectic symmetry, along with cluster formation, but slightly varies details that affect collective quadrupole moments, asymptotic normalization coefficients, and alpha partial widths up to a factor of two. This makes these types of emulators important for further constraining the nuclear force for high-precision nuclear structure and reaction observables.