Two-component droplet phases and their spectral stability in one dimension

Abstract: We unravel the existence and stability properties of one-dimensional droplets arising in genuine two-component particle imbalanced bosonic mixtures under the influence of a weak harmonic confinement. A plethora of miscible droplet phases is found with the majority component atoms in the vicinity of the minority ones assembling in a droplet configuration while the remaining excess atoms being in the gas state. Our computations identify a transition from a bound to a trapped gas many-body state for increasing total atom number and fixed interactions, with the bound character being prolonged for stronger intercomponent attractions. Spectral stability of these two-component droplets is revealed by examining their underlying Bogoliubov-de-Gennes excitation spectrum. Furthermore, the collective dynamics associated with the fundamental dipole and breathing modes of the system is monitored by suddenly shifting the trap's center or quenching the trap's frequency, respectively. There, a back action of the significantly localized minority component is imprinted in the majority cloud. The present findings can be simulated in recent cold-atom experiments, thus setting the stage for probing the complex nonequilibrium dynamics of two-component droplets.