Complex-energy eigenvector continuation for nuclear many-body broad resonances

Abstract

Broad resonances are a unique phenomenon in nuclear many-body systems. Theoretical studies usually involve the continuum degree of freedom, which drastically increases the model space of calculations, and may lead to non-convergence or instability of computations. In this paper, we present the extension of the eigenvector continuation (EC) method to the complex-energy space to treat the broad resonances of open quantum systems of nuclei. EC provides an efficient method to predict the solution of a large-space many-body problem within a small subspace. Using only a few bound and narrow resonance solutions as input in EC, we can obtain the solution of a broad resonance. We have applied the complex-energy EC to the broad resonances of ${}^4$H, four-neutron ${}^{4}n$, ${}^6$He and ${}^7$He systems.

Comments: 7 pages, 4 figures, 1 table; accepted by Physics Letters B