Snapshot-based Emulators for Chiral EFT Observables*

Bayesian nucleon-nucleon (NN) uncertainty quantification (UQ) has proven useful in helping understand to what extent our models work, but the process is known to be computationally expensive when using direct calculation methods. Recently, emulators have shown to provide fast & accurate™ predictions of bound state and scattering observables for applications that require repeated calculations with different parameters. The emulation process is performed by creating a basis of eigensolutions for several sets of known parameters to accurately interpolate and extrapolate solutions for the same Hamiltonian with different parameters. Here we provide a comparison between a Lippmann-Schwinger (LS) equation emulator and the KVP momentum-space emulator for a representative set of NN observables, with an alternate quasi-spline-based approach to speed up the KVP-based emulator. In addition, we apply a method to deal with the anomalies that appear in the emulation result.