  We study the ground-state properties of self-bound dipolar droplets in
quasi-two-dimensional geometry by using the Gaussian state theory. We show that
there exist two quantum phases corresponding to the macroscopic squeezed vacuum
and squeezed coherent states. We further show that the radial size versus atom
number curve exhibits a double-dip structure, as a result of the multiple
quantum phases. In particular, we find that the critical atom number for the
self-bound droplets is determined by the quantum phases, which allows us to
distinguish the quantum state and validates the Gaussian state theory.
