Converging sequences in the ab initio no-core shell model

TL;DR

This paper explores multiple converging sequences in the ab initio no-core shell model, proposing a new strategy for effective interactions that improves calculations of nuclear processes involving states of different parities.

Contribution

It introduces a revised approach for evaluating effective interactions in the no-core shell model, supported by large-scale calculations in light nuclei.

Findings

Multiple converging sequences exist in the no-core shell model.

The new strategy enhances the accuracy of nuclear transition rate calculations.

Demonstrated effectiveness in light nuclei calculations.

Abstract

We demonstrate the existence of multiple converging sequences in the ab initio no-core shell model. By examining the underlying theory of effective operators, we expose the physical foundations for the alternative pathways to convergence. This leads us to propose a revised strategy for evaluating effective interactions for $A$-body calculations in restricted model spaces. We suggest that this strategy is particularly useful for applications to nuclear processes in which states of both parities are used simultaneously, such as for transition rates. We demonstrate the utility of our strategy with large-scale calculations in light nuclei.