Ground and excited states of coupled exciton liquids in electron-hole quadrilayers

Interlayer excitons are bound states of electrons and holes confined in separate two-dimensional layers. Due to their repulsive dipolar interaction, interlayer can form a correlated liquid. If another electron-hole bilayer is present, from different bilayers exhibit mutual attraction. We study such quadrilayer system by hypernetted chain formalism. compute ground-state energies, pair correlation functions, collective mode velocities as functions the exciton densities. estimate critical density for transition paired biexciton phase. For strongly unbalanced (unequal density) system, more dilute behave polarons. energies effective masses exciton-polarons.