2023/02/01 by Chergui, L., Bengtsson, J., Bjerlin, J. +3 · 3 citations
#FOS: Physical sciences #Quantum Gases (cond-mat.quant-gas) #Quantum Physics (quant-ph)
paper · doi:10.48550/arxiv.2302.00385
We investigate the formation of self-bound quantum droplets in a one-dimensional binary mixture of bosonic atoms, applying the method of numerical diagonalization of the full Hamiltonian. The excitation spectra and ground-state pair correlations signal the formation of a few-boson droplet when crossing the region of critical inter-species interactions. The self-binding affects the rotational excitations, displaying a change in the energy dispersion from negative curvature, associated with superfluidity in the many-body limit, to a nearly parabolic curvature indicative of rigid body rotation. We exploit two global symmetries of the system to further analyze the few-body modes in terms of transition matrix elements and breathing mode dynamics. The exact results are compared to the usual ad-hoc inclusion of higher-order contributions in the extended Gross-Pitaevskii equation, showing a remarkable agreement between the few-body regime and the thermodynamic limit in one dimension.