Effective-interaction approach to the many-boson problem

TL;DR

This paper introduces an effective-interaction approach, adapted from nuclear physics, to improve the convergence and computational efficiency of many-boson numerical diagonalization in strongly interacting systems, accurately estimating energies and spectra.

Contribution

It applies the Lee-Suzuki effective interaction method to many-boson problems, significantly reducing computational costs while maintaining accuracy.

Findings

Enhanced convergence of numerical diagonalization

Accurate energy and spectrum estimates with smaller Hilbert spaces

Computational cost reduced by several orders of magnitude

Abstract

We show that the convergence behavior of the many-body numerical diagonalization scheme for strongly interacting bosons in a trap can be significantly improved by the Lee-Suzuki method adapted from nuclear physics: One can construct an effective interaction that acts in a space much smaller than the original Hilbert space. In particular for short-ranged forces and strong correlations, the method offers a good estimate of the energy and the excitation spectrum, at a computational cost several orders of magnitude smaller than that required by the standard method.