Confined few-particle systems beyond mean-field theory adopting Gaussian-type orbitals and Morse interparticle interaction

Recent advancements in optical tweezers enable the trapping of arbitrary numbers of neutral atoms and molecules, and even arrays of tweezers with variable geometry can be realized. These fascinating breakthroughs require novel full-dimensional beyond mean-field treatments for systems with more than two confined particles spread over traps that are arranged arbitrarily in space. In this work, the suitability of a quantum-chemistry inspired approach adopting Cartesian Gaussians as basis functions is investigated. For this purpose, the six-dimensional integrals associated with a realistic atom-atom interaction described by a Morse model potential were implemented. The performance, correctness, and efficiency of the implementation is assessed by comparing full configuration-interaction calculations (exact diagonalizations) for two atoms in an isotropic harmonic trap with quasiexact reference results.