Population imbalance steers droplet patterns in dipolar quantum gas

A mean-field study maps the ground-state morphologies of a two-component dipolar Bose-Einstein condensate confined in a circular 2D box, varying axial confinement, interaction strength, and population ratio. The system cycles through pancake states, droplet arrays, and concentric rings, with population imbalance acting like a volume fraction in block-copolymer microphase separation. The characteristic pattern spacing grows linearly with axial confinement length, but in a finite box this smooth trend breaks into discrete jumps as geometry forces integer numbers of rings or droplets — a clean signature of finite-size frustration. The work positions box-trapped dipolar mixtures as a tunable testbed for studying how boundary conditions and quantum fluctuations jointly govern self-organized structure.