Fast emulators for solving quantum few-body problems*

A common bottleneck issue in solving quantum few-body problems in hadronic, nuclear, and atomic physics is expensive computing costs. It restricts or even precludes many desirable calculations, such as theory calibrations. An emulator can be used to solve this issue. It is first trained on the exact solutions of the few-body problem at a small set of points in the theory parameter space. It is then used to make fast predictions at other points in the same space.

In this talk, I will summarize our developments of three-body scattering emulators (arXiv: 2110.04269) based on the eigenvector continuation (EC) concept. I will then focus on our ongoing work on similar emulators for few-hadron systems, which are valuable for applying complex coupled-channel models in analyzing various hadronic physics experiments. A future outlook will be presented in the end.