Anisotropic coherence properties in a trapped quasi-two-dimensional dipolar gas

We consider a trapped quasi-two-dimensional dipolar Bose-Einstein condensate with a polarization tilted into the plane of motion. We show that by tilting the polarization axis, the coherence properties are anisotropic. Such a system will have density fluctuations, the amplitude of which depends on their trap location. Additionally, interference contrast will also be anisotropic despite an isotropic density profile. The anisotropy is related to a rotonlike mode that becomes unstable and supports local collapse along the polarization axis.