Superfluid flow above the critical velocity

Paris-Mandoki, A, Shearring, J, Mancarella, F, Fromhold, T M, Trombettoni, A and Krüger, P (2017) Superfluid flow above the critical velocity. Scientific Reports, 7 (9070). pp. 195-11. ISSN 2045-2322

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Abstract

Superfluidity and superconductivity have been widely studied since the last century in many different contexts ranging from nuclear matter to atomic quantum gases. The rigidity of these systems with respect to external perturbations results in frictionless motion for superfluids and resistance-free electric current flow in superconductors. This peculiar behaviour is lost when external perturbations overcome a critical threshold, i.e. above a critical magnetic field or a critical current for superconductors. In superfluids, such as liquid helium or ultracold gases, the corresponding quantities are a critical rotation rate and a critical velocity respectively. Enhancing the critical values is of great fundamental and practical value. Here we demonstrate that superfluidity can be completely restored for specific, arbitrarily large flow velocities above the critical velocity through quantum interference-induced resonances providing a nonlinear counterpart of the Ramsauer-Townsend effect occurring in ordinary quantum mechanics. We illustrate the robustness of this phenomenon through a thorough analysis in one dimension and prove its generality by showing the persistence of the effect in non-trivial 2d systems. This has far reaching consequences for the fundamental understanding of superfluidity and superconductivity and opens up new application possibilities in quantum metrology, e.g. in rotation sensing.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Research Centres and Groups: Atomic, Molecular and Optical Physics Research Group
Subjects: Q Science > QC Physics
Depositing User: Richard Chambers
Date Deposited: 23 Oct 2018 13:01
Last Modified: 02 Jul 2019 14:15
URI: http://sro.sussex.ac.uk/id/eprint/79654

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