ROSE: A reduced-order scattering emulator for optical models

TL;DR

ROSE is a novel reduced basis emulator designed for efficient and accurate Bayesian calibration of optical scattering models, enabling fast uncertainty quantification in complex non-affine problems.

Contribution

The paper introduces ROSE, a reduced-order emulator capable of handling non-affine optical scattering problems within a Bayesian framework, improving speed and accuracy.

Findings

ROSE effectively calibrates nucleon-target scattering models.

It provides a practical tool for Bayesian uncertainty quantification.

ROSE balances emulator speed and accuracy in complex models.

Abstract

A new generation of phenomenological optical potentials requires robust calibration and uncertainty quantification, motivating the use of Bayesian statistical methods. These Bayesian methods usually require calculating observables for thousands or even millions of parameter sets, making fast and accurate emulators highly desirable or even essential. Emulating scattering across different energies or with interactions such as optical potentials is challenging because of the non-affine parameter dependence, meaning the parameters do not all factorize from individual operators. Here we introduce and demonstrate the Reduced Order Scattering Emulator (ROSE) framework, a reduced basis emulator that can handle non-affine problems. ROSE is fully extensible and works within the publicly available BAND Framework software suite for calibration, model mixing, and experimental design. As a demonstration problem, we use ROSE to calibrate a realistic nucleon-target scattering model through the calculation of elastic cross sections. This problem shows the practical value of the ROSE framework for Bayesian uncertainty quantification with controlled trade-offs between emulator speed and accuracy as compared to high-fidelity solvers. Planned extensions of ROSE are discussed.