Operating Nanobeams in a Quantum Fluid

Area of Science:

• Physics
• Quantum Fluids
• Nanotechnology

Background:

• Micro- and nanoelectromechanical systems (MEMS/NEMS) offer unique capabilities for probing quantum fluids due to their reproducibility, broad frequency range, and low power dissipation.
• Their small scale allows for investigations at the nanoscale, comparable to or below the coherence length of superfluids.
• Previous attempts to measure NEMS resonators in liquid helium phases have been unsuccessful.

Purpose of the Study:

• To report the successful operation of nanomechanical resonators in superfluid 4He.
• To demonstrate the sensitivity of these devices to superfluid properties.
• To establish a foundation for future experiments in superfluid 3He.

Main Methods:

• Fabrication of doubly-clamped aluminum nanobeams.
• Operation of nanobeams in superfluid 4He across the superfluid transition temperature.
• Measurement of nanobeam response to detect superfluid density and normal fluid damping.

Main Results:

• Demonstrated successful operation of NEMS resonators in superfluid 4He.
• Showcased high sensitivity of the nanobeams to superfluid density.
• Observed significant sensitivity to normal fluid damping effects.

Conclusions:

• Nanomechanical resonators are effective tools for studying superfluid helium.
• The successful operation in 4He paves the way for experiments in superfluid 3He.
• Future applications could explore the quantum ground state of nanomechanical devices at ultralow temperatures.