Coupled pair approach for strongly-interacting trapped fermionic atoms

TL;DR

This paper introduces a coupled pair approach using a stochastic variational Gaussian expansion to accurately study the ground state and structural properties of strongly interacting few-fermion systems in harmonic traps, with implications for many-body physics.

Contribution

The paper develops a novel coupled pair method with stochastic variational optimization for analyzing strongly interacting trapped fermions, achieving high accuracy with minimal computational effort.

Findings

Accurately computed ground state energies for 4, 6, and 8 fermions.

Analyzed structural properties of few-fermion systems.

Discussed implications for many-body ultracold gases.

Abstract

We present a coupled pair approach for studying few-body physics in harmonically trapped ultracold gases. The method is applied to a two-component Fermi system of $N$ particles. A stochastically variational gaussian expansion method is applied, focusing on optimization of the two-body correlations present in the strongly interacting, or unitary, limit. The groundstate energy of the four-, six- and eight-body problem with equal spin populations is calculated with high accuracy and minimal computational effort. We also calculate the structural properties of these systems and discuss their implication for the many-body ultracold gas and other few-body calculations.