Vortex lattice in the crossover of a Bose gas from weak coupling to unitarity

TL;DR

This paper investigates the vortex lattice formation in a Bose gas across the weak-coupling to unitarity crossover using advanced simulations, providing key benchmarks for experimental validation.

Contribution

It introduces a high-fidelity numerical approach to study vortex lattices in Bose gases across the interaction strength spectrum, incorporating a realistic equation of state.

Findings

Numerical predictions of vortex numbers across the crossover.

Root-mean-square size variations with interaction strength.

Validation benchmarks for future experimental studies.

Abstract

The formation of a regular lattice of quantized vortices in a fluid under rotation is a smoking-gun signature of its superfluid nature. Here we study the vortex lattice in a dilute superfluid gas of bosonic atoms at zero temperature along the crossover from the weak-coupling regime, where the inter-atomic scattering length is very small compared to the average distance between atoms, to the unitarity regime, where the inter-atomic scattering length diverges. This study is based on high-performance numerical simulations of the time-dependent nonlinear Schrodinger equation for the superfluid order parameter in three spatial dimensions, using a realistic analytic expression for the bulk equation of state of the system along the crossover from weak-coupling to unitarity. This equation of state has the correct weak-coupling and unitarity limits and faithfully reproduces the results of an accurate multi-orbital microscopic calculation. Our numerical predictions of the number of vortices and root-mean-square sizes are important benchmarks for future experiments.