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Article
Open AccessOperating Nanobeams in a Quantum Fluid
Microelectromechanical (MEMS) and nanoelectromechanical systems (NEMS) are ideal candidates for exploring quantum fluids, since they can be manufactured reproducibly, cover the frequency range from hundreds of...
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Article
Open AccessOn-chip magnetic cooling of a nanoelectronic device
We demonstrate significant cooling of electrons in a nanostructure below 10 mK by demagnetisation of thin-film copper on a silicon chip. Our approach overcomes the typical bottleneck of weak electron-phonon sc...
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Article
Breaking the superfluid speed limit in a fermionic condensate
An experiment reports the unexpected behaviour of an object in uniform motion in superfluid helium-3 above the Landau critical velocity — the limit above which it can generate excitations at no energy cost.
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Article
Probing Bogoliubov Quasiparticles in Superfluid \(^3\) He with a ‘Vibrating-Wire Like’ MEMS Device
We have measured the interaction between superfluid \(^3\) ...
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Article
Open AccessA Quasiparticle Detector for Imaging Quantum Turbulence in Superfluid \(^3\) He-B
We describe the development of a two-dimensional quasiparticle detector for use in visualising quantum turbulence in superfluid \(^3\) ...
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Article
Open AccessAnomalous Dam** of a Low Frequency Vibrating Wire in Superfluid 3He-B due to Vortex Shielding
We have investigated the behaviour of a large vibrating wire resonator in the B-phase of superfluid 3He at zero pressure and at temperatures below 200 μK. The vibrating wire has a low resonant frequency of around...
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Article
Open AccessResponse of a Mechanical Oscillator in Solid 4He
We present the first measurements of the response of a mechanical oscillator in solid 4He. We use a lithium niobate tuning fork operating in its fundamental resonance mode at a frequency of around 30 kHz. Measure...
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Article
Open AccessHysteresis, Switching and Anomalous Behaviour of a Quartz Tuning Fork in Superfluid 4He
We have been studying the behaviour of commercial quartz tuning forks immersed in superfluid 4He and driven at resonance. For one of the forks we have observed hysteresis and switching between linear and non-line...
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Article
Open AccessPlastic Properties of Solid 4He Probed by a Moving Wire: Viscoelastic and Stochastic Behavior Under High Stress
We present measurements of a thin wire moving through solid 4He. Measurements were made over a wide temperature range at pressures close to the melting curve. We describe the new experimental technique and presen...
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Article
Thermometry in Normal Liquid 3He Using a Quartz Tuning Fork Viscometer
We have developed the use of quartz tuning forks for thermometry in normal liquid 3He. We have used a standard 32 kHz tuning fork to measure the viscosity of liquid 3He over a wide temperature range, 6 mK<T<1.8 K...
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Article
The Onset of Vortex Production by a Vibrating Wire in Superfluid 3He-B
We present measurements of the force-velocity response of a vibrating wire resonator in superfluid 3He-B at very low temperatures. At low velocities the response is dominated by intrinsic (vacuum) dam** whilst ...
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Article
A New Device for Studying Low or Zero Frequency Mechanical Motion at Very Low Temperatures
We have developed a new “floppy wire” device for studying the motion through quantum fluids and solids at very low temperatures. The device is particularly well suited for producing large amplitudes of motion,...
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Article
Direct measurement of the energy dissipated by quantum turbulence
It is difficult to measure the turbulent energy in a classical system as the turbulence contributes only a small kinetic energy compared with the enthalpy of the system. A quantum system, however, such as liqu...
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Article
History Dependence of Turbulence Generated by a Vibrating Wire in Superfluid 4He at 1.5 K
We report on the onset of turbulence in normal and superfluid 4He using several 13.5 μm diameter vibrating wire resonators placed in a cell, filtered from the surrounding helium bath. We measured the force-veloci...
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Article
Measuring the Prong Velocity of Quartz Tuning Forks Used to Probe Quantum Fluids
Recently, quartz tuning forks have been used to probe the dynamics of quantum fluids. For many of these measurements it is important to know the velocity amplitude of the tips of the vibrating fork prongs. We ...
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Article
The Dam** of a Quartz Tuning Fork in Superfluid 3He-B at Low Temperatures
We have measured the dam** on a quartz tuning fork in the B-phase of superfluid 3He at low temperatures, below 0.3T c. We present extensive measurements of the velocity dependence and te...
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Article
Transition to Turbulence for a Quartz Tuning Fork in Superfluid 4He
We have studied the resonance of a commercial quartz tuning fork immersed in superfluid 4He, at temperatures between 5 mK and 1 K, and at pressures between zero and 25 bar. The force-velocity curves for the tunin...
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Article
The Transition to Turbulent Drag for a Cylinder Oscillating in Superfluid 4He: A Comparison of Quantum and Classical Behavior
We have measured the drag and inertial forces on wire resonators in superfluid 4He at millikelvin temperatures. At low velocities the behavior is dominated by the intrinsic properties of the resonators which can ...
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Article
Grid Turbulence in Superfluid 3He-B at Low Temperatures
Quantum turbulence consists of a tangle of quantised vortex lines which interact via their self induced flow. At very low temperatures there is no normal fluid component and no associated viscosity. These are...
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Article
Magnetic Distortion of the B-like Phase of Superfluid 3He Confined in Aerogel
We present measurements of the response of the B-like phase of superfluid 3He in aerogel to an applied flow. The measurements are made using a cylindrical piece of 98% silica aerogel attached to a vibrating wire...
