Universal relations for dipolar quantum gases

We establish that two-dimensional dipolar quantum gases admit a universal description, i.e., their thermodynamic properties are independent of details the interaction at short distances. The only relevant parameters dipole length as well scattering combined short-range plus potential. derive adiabatic relations link change in potentials with respect to and generalized Tan contact parameter new contact, which involves an integral short-distance regularized pair distribution function. These two quantities determine scale anomaly difference between pressure energy density also internal presence harmonic confinement. For weak transverse confinement, configurations attractive interactions appear, lead density-wave instability beyond critical strength interaction. show this essentially coincides onset roton minimum excitation spectrum may be understood terms analog Hansen-Verlet criterion for freezing classical fluid.Received 2 August 2020Revised 7 November 2020Accepted 16 January 2021DOI:https://doi.org/10.1103/PhysRevResearch.3.013088Published by American Physical Society under Creative Commons Attribution 4.0 International license. Further work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)Research AreasDipolar gasesPhysical SystemsSmectic liquid crystalsSuperfluidsSupersolidsUltracold gasesAtomic, Molecular & OpticalCondensed Matter, Materials Applied Physics