Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

Extreme nonlinear damping by the quasiparticle gas in superfluid B3 in the low-temperature limit

J. P. Carney, A. M. Guénault, G. R. Pickett, Gregory F. Spencer

Published Jun 26, 1989• 112 citations
Publisher

Abstract

The resistance to motion of a wire in superfluid $^{3}\mathit{B}$ has three contributions: that due to the internal friction of the resonator; that due to pair breaking; and that due to the quasiparticle gas. We have been able to separate quasiparticle contribution and find that it is highly nonlinear with velocity on the scale of the Landau velocity, \ensuremath{\Delta}/${\mathrm{p}}_{\mathrm{F}}$, and falls with increasing velocity. This indicates that the quasiparticle resistance is also governed by the condensate, almost certainly through Andreev reflection in the flow field around the wire.

DOI
10.1103/physrevlett.62.3042

Related papers

Probing Bogoliubov Quasiparticles in Superfluid $$^3$$ 3 He with a ‘Vibrating-Wire Like’ MEMS Device

Martial Defoort, Sébastien Dufresnes, S. L. Ahlstrom +11 more

We have measured the interaction between superfluid 3He–B and a micro-machined goalpost-shaped device at temperatures below 0.2Tc. The measured damping follows well the theory developed for vibrating wires, in which the Andreev reflection of quasiparticles in the flow field around the moving structure leads to a nonlinear frictional force. At low velocities, the damping force is proportional to velocity, while it tends to saturate for larger excitations. Above a velocity of 2.6 mm s−1, the damping abruptly increases, which is interpreted in terms of Cooper-pair breaking. Interestingly, this critical velocity is significantly lower than that reported with other mechanical probes immersed in superfluid 3He. Furthermore, we report on a nonlinear resonance shape for large motion amplitudes that we interpret as an inertial effect due to quasiparticle friction, but other mechanisms could possibly be invoked as well.

•May 1, 2016•16 citations

Anomalous Damping of a Low Frequency Vibrating Wire in Superfluid 3He-B due to Vortex Shielding

D. I. Bradley, M. J. Fear, S. N. Fisher +6 more

We have investigated the behaviour of a large vibrating wire resonator in the B-phase of superfluid 3 He at zero pressure and at temperatures below 200 μK. The vibrating wire has a low resonant frequency of around 60 Hz. At low velocities the motion of the wire is impeded by its intrinsic (vacuum) damping and by the scattering of thermal quasiparticle excitations. At higher velocities we would normally expect the motion to be further damped by the creation of quasiparticles from pair-breaking. However, for a range of temperatures, as we increase the driving force we observe a sudden decrease in the damping of the wire. This results from a reduction in the thermal damping arising from the presence of quantum vortex lines generated by the wire. These vortex lines Andreev-reflect low energy excitations and thus partially shield the wire from incident thermal quasiparticles.

Journal of Low Temperature Physics•Oct 1, 2013•2 citations

Landau critical velocity for a macroscopic object moving in superfluid B3 : Evidence for gap suppression at a moving surface

C. A. M. Castelijns, K. F. Coates, A. M. Guénault +2 more

We have observed that the motion of a vibrating-wire resonator in superfluid $^{3}\mathit{B}$ at temperatures below ${\mathrm{T}}_{\mathrm{c}}$/8 is associated with a sharp critical velocity, ${\mathrm{v}}_{\mathrm{c}}$, above which very high dissipation sets in. We identify this velocity with the Landau critical velocity for pair breaking. That the observed value of ${\mathrm{v}}_{\mathrm{c}}$ is a factor of 2 lower than the critical velocity expected from the BCS value of the gap we take as evidence that the gap is suppressed by about 50% of its bulk value near a moving boundary.

Physical Review Letters•Jan 6, 1986•145 citations

Beyond the two-fluid model: Transition from linear behavior to a velocity-independent force on a moving object in B3

S. N. Fisher, A. M. Guénault, C. J. Kennedy +1 more

Using a simple one-dimensional model, we show that the existence of the energy gap for excitations in an isotropic BCS superfluid leads to strongly nonlinear mechanical behavior of the liquid in the ballistic quasiparticle limit. The nonlinear damping of a vibrating wire in $^{3}\mathit{B}$ below 200 \ensuremath{\mu}K is explained, both in its velocity dependence and magnitude. At modest velocities (\ensuremath{\upsilon}>kT/${\mathrm{p}}_{\mathrm{F}}$), the damping force on an object moving through the superfluid becomes independent of velocity, an unexpected result with several interesting implications.

Physical Review Letters•Dec 4, 1989•163 citations

Critical Velocity in the Presence of Surface Bound States in Superfluid He3−B

P. Zheng, W. G. Jiang, C. S. Barquist +2 more

A microelectromechanical oscillator with a gap of 1.25 μm was immersed in superfluid ^{3}He-B and cooled below 250 μK at various pressures. Mechanical resonances of its shear motion were measured at various levels of driving force. The oscillator enters into a nonlinear regime above a certain threshold velocity. The damping increases rapidly in the nonlinear region and eventually prevents the velocity of the oscillator from increasing beyond the critical velocity which is much lower than the Landau critical velocity. We propose that this peculiar nonlinear behavior stems from the escape of quasiparticles from the surface bound states into the bulk fluid.

arXiv:1610.02347•Physical Review Letters•Feb 8, 2017•21 citations

Models for supercritical motion in a superfluid Fermi liquid

J. A. Kuorelahti, Sami Laine, E. V. Thuneberg

We study the drag force on objects moving in a Fermi superfluid at velocities on the order of the Landau velocity ${v}_{L}$. The expectation has been that ${v}_{L}$ is the critical velocity beyond which the drag force starts to increase toward its normal-state value. This expectation is challenged by a recent experiment measuring the heat generated by a uniformly moving wire immersed in superfluid $^{3}\mathrm{He}$. We introduce the basis for the calculation of the drag force on a macroscopic object using the Fermi-liquid theory of superfluidity. As a technical tool in the calculations, we propose a boundary condition that describes diffuse reflection of quasiparticles from a surface on a scale that is larger than the superfluid coherence length. We calculate the drag force on steadily moving objects of different sizes. For an object that is small compared to the coherence length, we find a drag force that is in accordance with the expectation. For a macroscopic object, we need to take into account the spatially varying flow field around the object. At low velocities, this arises from ideal flow of the superfluid. At higher velocities, the flow field is modified by excitations that are created when the flow velocity locally exceeds ${v}_{L}$. The flow field causes Andreev reflection of quasiparticles and thus leads to change in the drag force. We calculate multiple limiting cases for a cylinder-shaped object. In the absence of quasiparticle-quasiparticle collisions, we find that the critical velocity is larger than ${v}_{L}$ and the drag force (per cross-sectional area) at $2{v}_{L}$ is reduced by an order of magnitude compared to the case of a small object. In a collision-dominated limit, the flow shows signs of instability at a velocity below ${v}_{L}$.

arXiv:1806.02554•Physical review. B./Physical review. B•Oct 16, 2018•13 citations
The resistance to motion of a wire in superfluid 3B^{3}\mathit{B}3B has three contributions: that due to the internal friction of the resonator; that due to pair breaking; and that due to the quasiparticle gas. We have been able to separate quasiparticle contribution and find that it is highly nonlinear with velocity on the scale of the Landau velocity, \ensuremath{\Delta}/pF{\mathrm{p}}_{\mathrm{F}}pF​, and falls with increasing velocity. This indicates that the quasiparticle resistance is also governed by the condensate, almost certainly through Andreev reflection in the flow field around the wire.
Probing Bogoliubov Quasiparticles in Superfluid 3^33 3 He with a ‘Vibrating-Wire Like’ MEMS Device
We have measured the interaction between superfluid 3He–B and a micro-machined goalpost-shaped device at temperatures below 0.2Tc. The measured damping follows well the theory developed for vibrating wires, in which the Andreev reflection of quasiparticles in the flow field around the moving structure leads to a nonlinear frictional force. At low velocities, the damping force is proportional to velocity, while it tends to saturate for larger excitations. Above a velocity of 2.6 mm s−1, the damping abruptly increases, which is interpreted in terms of Cooper-pair breaking. Interestingly, this critical velocity is significantly lower than that reported with other mechanical probes immersed in superfluid 3He. Furthermore, we report on a nonlinear resonance shape for large motion amplitudes that we interpret as an inertial effect due to quasiparticle friction, but other mechanisms could possibly be invoked as well.
We have investigated the behaviour of a large vibrating wire resonator in the B-phase of superfluid 3 He at zero pressure and at temperatures below 200 μK. The vibrating wire has a low resonant frequency of around 60 Hz. At low velocities the motion of the wire is impeded by its intrinsic (vacuum) damping and by the scattering of thermal quasiparticle excitations. At higher velocities we would normally expect the motion to be further damped by the creation of quasiparticles from pair-breaking. However, for a range of temperatures, as we increase the driving force we observe a sudden decrease in the damping of the wire. This results from a reduction in the thermal damping arising from the presence of quantum vortex lines generated by the wire. These vortex lines Andreev-reflect low energy excitations and thus partially shield the wire from incident thermal quasiparticles.
We have observed that the motion of a vibrating-wire resonator in superfluid 3B^{3}\mathit{B}3B at temperatures below Tc{\mathrm{T}}_{\mathrm{c}}Tc​/8 is associated with a sharp critical velocity, vc{\mathrm{v}}_{\mathrm{c}}vc​, above which very high dissipation sets in. We identify this velocity with the Landau critical velocity for pair breaking. That the observed value of vc{\mathrm{v}}_{\mathrm{c}}vc​ is a factor of 2 lower than the critical velocity expected from the BCS value of the gap we take as evidence that the gap is suppressed by about 50% of its bulk value near a moving boundary.
Using a simple one-dimensional model, we show that the existence of the energy gap for excitations in an isotropic BCS superfluid leads to strongly nonlinear mechanical behavior of the liquid in the ballistic quasiparticle limit. The nonlinear damping of a vibrating wire in 3B^{3}\mathit{B}3B below 200 \ensuremath{\mu}K is explained, both in its velocity dependence and magnitude. At modest velocities (\ensuremath{\upsilon}>kT/pF{\mathrm{p}}_{\mathrm{F}}pF​), the damping force on an object moving through the superfluid becomes independent of velocity, an unexpected result with several interesting implications.
A microelectromechanical oscillator with a gap of 1.25 μm was immersed in superfluid ^{3}He-B and cooled below 250 μK at various pressures. Mechanical resonances of its shear motion were measured at various levels of driving force. The oscillator enters into a nonlinear regime above a certain threshold velocity. The damping increases rapidly in the nonlinear region and eventually prevents the velocity of the oscillator from increasing beyond the critical velocity which is much lower than the Landau critical velocity. We propose that this peculiar nonlinear behavior stems from the escape of quasiparticles from the surface bound states into the bulk fluid.
We study the drag force on objects moving in a Fermi superfluid at velocities on the order of the Landau velocity vL{v}_{L}vL​. The expectation has been that vL{v}_{L}vL​ is the critical velocity beyond which the drag force starts to increase toward its normal-state value. This expectation is challenged by a recent experiment measuring the heat generated by a uniformly moving wire immersed in superfluid 3He^{3}\mathrm{He}3He. We introduce the basis for the calculation of the drag force on a macroscopic object using the Fermi-liquid theory of superfluidity. As a technical tool in the calculations, we propose a boundary condition that describes diffuse reflection of quasiparticles from a surface on a scale that is larger than the superfluid coherence length. We calculate the drag force on steadily moving objects of different sizes. For an object that is small compared to the coherence length, we find a drag force that is in accordance with the expectation. For a macroscopic object, we need to take into account the spatially varying flow field around the object. At low velocities, this arises from ideal flow of the superfluid. At higher velocities, the flow field is modified by excitations that are created when the flow velocity locally exceeds vL{v}_{L}vL​. The flow field causes Andreev reflection of quasiparticles and thus leads to change in the drag force. We calculate multiple limiting cases for a cylinder-shaped object. In the absence of quasiparticle-quasiparticle collisions, we find that the critical velocity is larger than vL{v}_{L}vL​ and the drag force (per cross-sectional area) at 2vL2{v}_{L}2vL​ is reduced by an order of magnitude compared to the case of a small object. In a collision-dominated limit, the flow shows signs of instability at a velocity below vL{v}_{L}vL​.