Theoretical Uncertainty Quantification for Heavy-ion Fusion

TL;DR

This paper investigates the uncertainty in modeling heavy-ion fusion reactions using time-dependent Hartree-Fock, highlighting the significant impact of static property uncertainties and proposing the use of reaction data to improve model constraints.

Contribution

It introduces a theoretical framework for quantifying model uncertainty in heavy-ion fusion, emphasizing the role of static property uncertainties and suggesting data-driven model improvements.

Findings

Model uncertainty is significant for many systems studied.

Main uncertainty source is static properties like neutron radius.

Reaction data can help constrain models and static properties.

Abstract

Despite recent advances and focus on rigorous uncertainty quantification for microscopic models of quantum many-body systems, the uncertainty on the dynamics of those systems has been under-explored. To address this, we have used time-dependent Hartree-Fock to examine the model uncertainty for a collection of low-energy, heavy-ion fusion reactions. Fusion reactions at near-barrier energies represent a rich test-bed for the dynamics of quantum many-body systems owing to the complex interplay of collective excitation, transfer, and static effects that determine the fusion probability of a given system. While the model uncertainty is sizable for many of the systems studied, the primary contribution comes from ill-constrained static properties, such as the neutron radius of neutron-rich nuclei. These large uncertainties motivate the use of information from reactions to better constrain existing models and to infer static properties from reaction data.