  We study the thermodynamic liquid-gas transition and coexistence (LGTC) for
ground-state bosons under contact interactions. We find that the LGTC can be
facilitated by the mismatch of spin polarization, dubbed "spin twist," between
single-particle and interaction channels of bosons with spin degrees of
freedom. Such a spin twist uniquely stabilizes the gas phase by creating an
effective repulsion for low-density bosons, thereby enabling LGTC in the
presence of a quantum droplet at a much larger density. We have demonstrated
the scheme for binary bosons subject to Rabi coupling and magnetic detuning,
where the liquid-gas transition can be conveniently tuned and their coexistence
can be characterized by a discontinuous density profile in a harmonic trap. The
spin twist scheme for LGTC can be generalized to a wide class of quantum
systems with competing single-particle and interaction orders.
