Ultra-Low Dissipation Superfluid Micromechanical Resonator

TL;DR

This paper introduces superfluid micromechanical resonators with ultra-low dissipation, achieving high quality factors at cryogenic temperatures, and models their dissipation mechanisms to optimize quantum applications.

Contribution

It presents the design, fabrication, and quantitative modeling of superfluid micromechanical resonators with unprecedented quality factors at millikelvin temperatures.

Findings

Quality factors up to 913,000 at 13 mK achieved

Dissipation suppressed by cryogenic cooling and superfluid state

Potential to reach quality factors of 10^8 at 100 mK

Abstract

Micro and nanomechanical resonators with ultra-low dissipation have great potential as useful quantum resources. The superfluid micromechanical resonators presented here possess several advantageous characteristics: straightforward thermalization, dissipationless flow, and in situ tunability. We identify and quantitatively model the various dissipation mechanisms in two resonators, one fabricated from borosilicate glass and one from single crystal quartz. As the resonators are cryogenically cooled into the superfluid state, the damping from thermal effects and from the normal fluid component are strongly suppressed. At our lowest temperatures, damping is limited solely by internal dissipation in the substrate materials, and reach quality factors up to 913,000 at 13 mK. By lifting this limitation through substrate material choice and resonator design, modelling suggests that the resonators should reach quality factors as high as 10$^8$ at 100 mK, putting this architecture in an ideal position to harness mechanical quantum effects.