Probing Quantum Fluids with a Nanoelectromechanical Resonators

The project will involve the design, manufacture and investigation of microelectromechanical (MEMS) and NEMS resonators in vacuum and in superfluid helium. The goal is to study NEMS and MEMS that have a large length to width ratio and a high quality factor. The combination of moderate resonant frequencies (tens of megahertz) and ultralow temperatures (sub-millikelvin) will enable the quantum limit of the mechanical oscillator to be reached while also allowing the state of the resonator to be probed and manipulated on experimentally-accessible timescales. One of the milestones will be to understand and overcome existing cooling restrictions to reach sub-millikelvin temperatures. The resonators will also be employed as extremely sensitive probes of the superfluid, providing a unique physical system in which a quantum-limited mechanical sensor is coupled to a quantum fluid.