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Updated: Dec 13, 2025

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids
Published on: September 30, 2014
Superfluid Flow of Polaron Polaritons above Landau's Critical Velocity
K Knakkergaard Nielsen1, A Camacho-Guardian1, G M Bruun1,2
1Department of Physics and Astronomy, Aarhus University, Ny Munkegade, 8000 Aarhus C, Denmark.
Abstract:
We develop a theory for the interaction of light with superfluid optical media, describing the motion of quantum impurities that are created and dragged through the liquid by propagating photons. It is well known that a mobile impurity suffers dissipation due to phonon emission as soon as it moves faster than the speed of sound in the superfluid-Landau's critical velocity. Surprisingly we find that in the present hybrid light-matter setting, polaritonic impurities can be protected against environmental decoherence and be allowed to propagate well above the Landau velocity without jeopardizing the superfluid response of the medium.
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