A universal reduced basis for the calibration of covariant energy density functionals

TL;DR

This paper develops a universal reduced basis for Dirac orbitals to efficiently calibrate covariant energy density functionals across the nuclear chart, enabling faster and accurate Bayesian optimization.

Contribution

It introduces a reduced basis method tailored for the Dirac equation, addressing complexities from negative energy states, to improve calibration of energy density functionals.

Findings

Accurately reproduces high-fidelity models with reduced computational cost.

Provides a foundation for rapid emulators in nuclear physics.

Facilitates Bayesian optimization of energy density functionals.

Abstract

The reduced basis method is used to construct a "universal" basis of Dirac orbitals that may be applicable throughout the nuclear chart to calibrate covariant energy density functionals. Relative to our earlier work using the non-relativistic Schr\"odinger equation, the Dirac equation adds an extra layer of complexity due to the existence of negative energy states. However, once this problem is mitigated, the resulting reduced basis is able to accurately and efficiently reproduce the high-fidelity model at a fraction of the computational cost. We are confident that the resulting reduced basis will serve as a foundational element in developing rapid and accurate emulators. In turn, these emulators will play a critical role in the Bayesian optimization of covariant energy density functionals.