Energetic and Structural Properties of Two-Dimensional Trapped Mesoscopic Fermi Gases

TL;DR

This paper provides a comprehensive theoretical analysis of two-dimensional trapped mesoscopic Fermi gases, detailing their energetic, structural, and correlation properties using numerically exact methods, relevant for cold-atom experiments.

Contribution

It introduces a precise computational approach to study few-fermion systems in two dimensions, analyzing energies, correlations, and distributions with exact numerical methods.

Findings

Calculated energy spectra for up to six particles.

Analyzed non-local and local correlation functions.

Provided insights into momentum distributions and condensate fractions.

Abstract

We theoretically investigate equal-mass spin-balanced two-component Fermi gases in which pairs of atoms with opposite spins interact via a short-range isotropic model potential. We probe the distinction between two-dimensional and quasi-two-dimensional harmonic confinement by tuning the effective range parameter within two-dimensional scattering theory. Our approach, which yields numerically exact energetic and structural properties, combines a correlated Gaussian basis-set expansion with the stochastic variational method. For systems containing up to six particles, we: 1) Present the ground- and excited-state energy spectra; 2) Study non-local correlations by analysing the one- and two-body density matrices, extracting from these the occupation numbers of the natural orbitals, the momentum distributions of atoms and pairs, and the molecular 'condensate fraction'; 3) Study local correlations by computing the radial and pair distribution functions. This paper extends current theoretical knowledge on the properties of trapped few-fermion systems as realised in state-of-the-art cold-atom experiments.