An Efficient Learning Method to Connect Observables

Constructing fast and accurate surrogate models is a key ingredient for making robust predictions in many topics. We introduce a new model, the multiparameter eigenvalue problem (MEP) emulator. The new method connects emulators and can make predictions directly from observables to observables. We show that the MEP emulator can be trained with data from eigenvector continuation and parametric matrix model emulators. A simple simulation on a one-dimensional lattice confirms the performance of the MEP emulator. Using ^{28}O as an example, we also demonstrate that the predictive probability distribution of the target observables can be straightforwardly obtained through the new emulator.