Probing superfluid ${}^4\mathrm{He}$ with high-frequency nanomechanical resonators down to $\mathrm{mK}$ temperatures

Abstract

Superfluids, such as superfluid ${}^3\mathrm{He}$ and ${}^4\mathrm{He}$, exhibit a broad range of quantum phenomena and excitations which are unique to these systems. Nanoscale mechanical resonators are sensitive and versatile force detectors with the ability to operate over many orders of magnitude in damping. Using nanomechanical-doubly clamped beams of extremely high quality factors ($Q>10^6$), we probe superfluid ${}^4\mathrm{He}$ from the superfluid transition temperature down to $\mathrm{mK}$ temperatures at frequencies up to $11.6\mathrm{MHz}$. Our studies show that nanobeam damping is dominated by hydrodynamic viscosity of the normal component of ${}^4\mathrm{He}$ above $1\mathrm{K}$. In the temperature range $0.3-0.8\mathrm{K}$, the ballistic quasiparticles (phonons and rotons) determine the beams' behavior. At lower temperatures, damping saturates and is determined either by magnetomotive losses or acoustic emission into helium. It is remarkable that all these distinct regimes can be extracted with just a single device, despite damping changing over six orders of magnitude.

4 pages, 2 figures. arXiv admin note: text overlap with arXiv:1810.10129

References in corpus (3)

• A Mechanical Mass Sensor with Yoctogram Resolution
• Intrinsic dissipation in nanomechanical resonators due to phonon tunneling
• Layering transitions in superfluid helium adsorbed on a carbon nanotube mechanical resonator

Cited by in corpus (10)

• Mesoscopic physics of nanomechanical systems
• The dispersion relation of Landau elementary excitations and the thermodynamic properties of superfluid ${}^4$He
• Nanoscale Real-Time Detection of Quantum Vortices at Millikelvin Temperatures
• Fundamental dissipation due to bound fermions in the zero-temperature limit
• Detecting the "phonon wind" in superfluid ${}^4\mathrm{He}$ by a nanomechanical resonator
• Amplitude of waves in the Kelvin-wave cascade
• Dimensional control of tunneling two level systems in nanoelectromechanical resonators
• Superfluid ${}^4$He as a rigorous test bench for different damping models in nanoelectromechanical resonators
• Fully suspended nano-beams for quantum fluids
• Aluminum goalpost nano-mechanical devices at low temperatures