Quantum halo states in two-dimensional dipolar clusters

TL;DR

This paper predicts and characterizes quantum halo states with up to six bosonic dipolar atoms in a bilayer setup, revealing novel symmetric and anisotropic structures near unbinding thresholds.

Contribution

It introduces the first theoretical proposal for multi-atom halo states in dipolar gases and details their binding energies, spatial distributions, and unique structural features.

Findings

Identification of symmetric halo structures at large interlayer separation

Discovery of highly anisotropic halo shapes near unbinding threshold

Potential for experimental realization of large-atom halos in ultracold gases

Abstract

A halo is an intrinsically quantum object defined as a bound state of a spatial size which extends deeply into the classically forbidden region. Previously, halos have been observed in bound states of two and less frequently of three atoms. Here, we propose a realization of halo states containing as many as six atoms. We report the binding energies, pair correlation functions, spatial distributions, and sizes of few-body clusters composed by bosonic dipolar atoms in a bilayer geometry. We find two very distinct halo structures, for large interlayer separation the halo structure is roughly symmetric and we discover an unusual highly anisotropic shape of halo states close to the unbinding threshold. Our results open avenues of using ultracold gases for the experimental realization of halos with the largest number of atoms ever predicted before.