Breaking the superfluid speed limit

Abstract

Coherent condensates appear as emergent phenomena in many systems, sharing the characteristic feature of an energy gap separating the lowest excitations from the condensate ground state. This implies that a scattering object, moving through the system with high enough velocity for the excitation spectrum in the scatter frame to become gapless, can create excitations at no energy cost, initiating the breakdown of the condensate. This limit is the well-known Landau velocity. While, for the neutral Fermionic superfluid 3He-B in the T=0 limit, flow around an oscillating body displays a very clear critical velocity for the onset of dissipation, here we show that for uniform linear motion there is no discontinuity whatsoever in the dissipation as the Landau critical velocity is passed and exceeded. Since the Landau velocity is such a pillar of our understanding of superfluidity, this is a considerable surprise, with implications for the understanding of the dissipative effects of moving objects in all coherent condensate systems.

25 pages - article and figures plus supplementary methods

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Cited by in corpus (24)

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• Critical Velocity in the Presence of Surface Bound States in Superfluid ${}^3$He-B
• Operating Nanobeams in a Quantum Fluid
• Fundamental dissipation due to bound fermions in the zero-temperature limit
• Thermodynamic origin of the Landau instability of superfluids
• Models for supercritical motion in a superfluid Fermi liquid
• Thermal transport of helium-3 in a strongly confining channel
• New Phases of Superfluid ${}^3$He Confined in Aerogels
• Landau velocity for collective quantum Hall breakdown in bilayer graphene
• Effect of boundary condition on Kapitza resistance between superfluid ${}^3$He-B and sintered metal
• Superfluid flow of polaron polaritons above Landau's critical velocity
• Induced supersolidity and hypersonic flow of a dipolar Bose-Einstein Condensate in a rotating bubble trap
• Design of a system for controlling a levitating sphere in superfluid ${}^3$He at extremely low temperatures
• Surface State Dissipation in Confined 3He-A
• Transport of bound quasiparticle states in a two-dimensional boundary superfluid
• Vortex-mediated relaxation of magnon BEC into light Higgs quasiparticles
• NMR-like effect on Anisotropic Magnetic Moment of Surface Bound States in Topological Superfluid ${}^3$He-B
• Fully suspended nano-beams for quantum fluids
• Overcritical Fermi Superfluids
• Drag on Cylinders Moving in Superfluid 3He-B as the Dimension Spans the Coherence Length
• Superfluid ${}^3$He-B Surface States in a Confined Geometry Probed by a Microelectromechanical Oscillator