Excitations and anisotropic sound in planar dipolar supersolids with tilted dipoles

TL;DR

This paper explores the anisotropic collective excitations and sound propagation in tilted dipolar supersolids confined in a plane, providing analytical and theoretical insights relevant to recent experimental observations.

Contribution

It introduces a unified theoretical framework for understanding anisotropic sound speeds and elastic properties in tilted dipolar supersolids, linking microscopic interactions to macroscopic dynamics.

Findings

Derived analytical expressions for sound speeds along principal axes.

Identified two orientational coefficients governing long-wavelength dynamics.

Connected theoretical predictions with recent experimental results.

Abstract

We investigate the collective excitations of anisotropic dipolar supersolids in planar confinement, focusing on triangular and stripe phases in situations where the dipoles are titled to have a component in the plane. Using Bogoliubov-de Gennes calculations and hydrodynamic theory, we identify the elastic parameters that govern the long-wavelength dynamics, including two orientational coefficients that capture the broken rotational symmetry induced by dipole tilt. Analytical expressions for the speeds of sound are obtained along the principal axes for triangular supersolids and along any propagation direction for the stripe supersolid. Our results provide a unified framework for understanding sound propagation in anisotropic dipolar supersolids and establish connections to recent experiments on sound propagation in striped Bose-Einstein condensates.