Ab-initio No-Core Gamow Shell Model calculations with realistic interactions

TL;DR

This paper applies the No-Core Gamow Shell Model with realistic interactions to helium isotopes, successfully describing bound and unbound states, and benchmarking against exact methods to validate its accuracy.

Contribution

It introduces the first application of NCGSM to helium isotopes using a complex energy formulation and benchmarks it with exact calculations, demonstrating its effectiveness for unstable nuclei.

Findings

Accurately describes bound and unbound helium states

Benchmarks agree with Faddeev and Faddeev-Yakubovsky results

Provides ab initio predictions for $^5$He properties

Abstract

No-Core Gamow Shell Model (NCGSM) is applied for the first time to study selected well-bound and unbound states of helium isotopes. This model is formulated on the complex energy plane and, by using a complete Berggren ensemble, treats bound, resonant, and scattering states on equal footing. We use the Density Matrix Renormalization Group method to solve the many-body Schr\"{o}dinger equation. To test the validity of our approach, we benchmarked the NCGSM results against Faddeev and Faddeev-Yakubovsky exact calculations for $^3$H and $^4$He nuclei. We also performed {\textit ab initio} NCGSM calculations for the unstable nucleus $^5$He and determined the ground state energy and decay width, starting from a realistic N$^3$LO chiral interaction.