Dynamical rigidity of dipolar supersolids*

Supersolidity is an exotic phase-of-matter[1], recently realized with long-range

anisotropically interacting dipolar quantum gases[2], where droplet crystals exist atop a

superfluid substrate. Here, we address the solidity and phase rigidity of ¹⁶⁴Dy quasi-1D

supersolids by initially separating them via a central potential barrier which is

subsequently released triggering their counterflow. The supersolid stripes undergo a

decaying oscillatory motion, which can be qualitatively captured by a model of coupled

springs. The decay is found to be proportional to the superfluid background density. The

phase rigidity of supersolids is monitored by imprinting a phase gradient across them.

The ensuing droplet peaks drift in unison, while featuring an out-of-phase motion with

their superfluid background. The drift speed can be controlled through the imprinted

phase gradient. Generalizations to quasi-2D supersolids are elucidated accompanied by

the formation of bulk and surface patterns.

References:

[1] A. J. Leggett, Phys. Rev. Lett. 25, 1543 (1970).

[2] L. Chomaz et al, Rep. Prog. Phys. 86, 026401 (2022).