plane. We present ground-state phase diagrams of the above system at different tilt angles. We find that as the dipolar interaction increases, the superfluid phase at half-filling factor is destroyed in favor of either a checkerboard or stripe solid phase for tilt angle

\ensuremath{\theta}\ensuremath{\lesssim}{30}^{\ensuremath{\circ}}

\ensuremath{\theta}\ensuremath{\gtrsim}{30}^{\ensuremath{\circ}}

, respectively. More interesting physics happens at tilt angles

\ensuremath{\theta}\ensuremath{\gtrsim}{58}^{\ensuremath{\circ}}

, where we find that as the dipolar interaction strength increases, solid phases first appear at filling factor lower than 0.5. Moreover, unlike what is observed at lower tilt angles, we find that at half filling, a stripe supersolid intervenes between the superfluid and stripe solid phase.

DOI: 10.1103/physreva.103.043333

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xz

\ensuremath{\theta}\ensuremath{\lesssim}{30}^{\ensuremath{\circ}}

\ensuremath{\theta}\ensuremath{\gtrsim}{30}^{\ensuremath{\circ}}

, respectively. More interesting physics happens at tilt angles

\ensuremath{\theta}\ensuremath{\gtrsim}{58}^{\ensuremath{\circ}}

xz

plane. We present ground state phase diagrams of the above system at different tilt angles. We find that, as the dipolar interaction increases, the superfluid phase at half filling factor is destroyed in favor of either a checkerboard or stripe solid phase for tilt angle

\theta \lesssim 35.3^{\circ}

\theta \gtrsim 35.3^{\circ}

respectively. More interesting physics happens at tilt angles

\theta \gtrsim 58^{\circ}

where we find that, as the dipolar interaction strength increases, solid phases first appear at filling factor lower than

0.5

. Moreover, unlike what observed at lower tilt angles at half filling, we find that the superfluid gives way to a stripe solid through a stripe supersolid phase.

φ=45^\circ

, we investigate density instabilities arising from first-order phase transitions. We start by mapping the ground-state phase diagram at half filling as a function of dipolar interaction strength and polar angle

θ

. For weak interactions, the system remains superfluid for all

θ

. Above a critical interaction strength, the superfluid phase becomes unstable and gives way to checkerboard, stripe, or incompressible phases depending on

θ

. For

θ\gtrsim 62^\circ

, we find that half filling becomes unstable and only the empty state,

n=0

, and the fully filled state,

n=1

, are stable. Unlike recent experimental reports of a self-bound insulator at half filling, the homogeneous ground state does not support such a phase, but instead exhibits a direct first-order transition between

n=0

and

n=1

. At finite temperature, thermal fluctuations shift the onset of density instabilities to larger

θ

and stabilize intermediate fillings in the regime where half filling is unstable in the ground state. This leads to phase-separated states consisting of empty and fully filled regions that resemble the experimentally observed "self-bound insulator." In a harmonic trap, similar structures also emerge from phase coexistence associated with the underlying first-order transition.

We analyze the ground state of a system of dipolar bosons moving in the

XY

plane and such that their dipolar moments are all aligned in a fixed direction in space. We focus on the general case where the polarization field forms a generic angle $\ensuremath{\alpha}$ with respect to the

Z

axis. We use the path-integral ground-state method to analyze the static properties of the system as both $\ensuremath{\alpha}$ and the density

n

vary over a wide range where the system is stable. We use the maximum of the static structure function as an order parameter to characterize the different phases and the transition lines among them. We find that, in addition to a superfluid gas and a solid phase, the system reaches a stripe phase at large tilting angles that is entirely induced by the anisotropic character of the interaction. We also show that the quantum phase transition from the gas to the stripe phase is of second order and report approximate values for the critical exponents.