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Title: Phase-Slip Avalanches in the Superflow of {sup 4}He through Arrays of Nanosize Apertures

Abstract

In response to recent experiments by the Berkeley group, we construct a model of superflow through an array of nanosize apertures that incorporates two basic ingredients: (1) disorder associated with each aperture having its own random critical velocity, and (2) effective interaperture coupling, mediated through the bulk superfluid. As the disorder becomes weak there is a transition from a regime where phase slips are largely independent to a regime where interactions lead to system-wide avalanches of phase slips. We explore the flow dynamics in both regimes, and make connections to the experiments.

Authors:
; ;  [1]
  1. Department of Physics, University of Illinois at Urbana-Champaign, 1110 West Green Street, Urbana, Illinois 61801-3080 (United States)
Publication Date:
OSTI Identifier:
20951280
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 17; Other Information: DOI: 10.1103/PhysRevLett.98.175301; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; APERTURES; CRITICAL VELOCITY; HELIUM 4; NANOSTRUCTURES; RANDOMNESS; SUPERFLUIDITY

Citation Formats

Pekker, David, Barankov, Roman, and Goldbart, Paul M. Phase-Slip Avalanches in the Superflow of {sup 4}He through Arrays of Nanosize Apertures. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.175301.
Pekker, David, Barankov, Roman, & Goldbart, Paul M. Phase-Slip Avalanches in the Superflow of {sup 4}He through Arrays of Nanosize Apertures. United States. doi:10.1103/PHYSREVLETT.98.175301.
Pekker, David, Barankov, Roman, and Goldbart, Paul M. Fri . "Phase-Slip Avalanches in the Superflow of {sup 4}He through Arrays of Nanosize Apertures". United States. doi:10.1103/PHYSREVLETT.98.175301.
@article{osti_20951280,
title = {Phase-Slip Avalanches in the Superflow of {sup 4}He through Arrays of Nanosize Apertures},
author = {Pekker, David and Barankov, Roman and Goldbart, Paul M.},
abstractNote = {In response to recent experiments by the Berkeley group, we construct a model of superflow through an array of nanosize apertures that incorporates two basic ingredients: (1) disorder associated with each aperture having its own random critical velocity, and (2) effective interaperture coupling, mediated through the bulk superfluid. As the disorder becomes weak there is a transition from a regime where phase slips are largely independent to a regime where interactions lead to system-wide avalanches of phase slips. We explore the flow dynamics in both regimes, and make connections to the experiments.},
doi = {10.1103/PHYSREVLETT.98.175301},
journal = {Physical Review Letters},
number = 17,
volume = 98,
place = {United States},
year = {Fri Apr 27 00:00:00 EDT 2007},
month = {Fri Apr 27 00:00:00 EDT 2007}
}
  • Experimental techniques to study dynamical light scattering phenomena in phase separating /sup 3/He--/sup 4/He liquid mixtures are described. Commercially available self-scanning 512-element linear photodiode arrays are used to record ''snapshots'' of small-angle light scattering patterns with high angular resolution at time intervals as short as 2 ms. Logic circuitry developed for interfacing the photodiode arrays with a digital oscilloscope recorder is described in detail.
  • It is shown that the superfluid turbulence arises as a convective, not an absolute, instability. A continuous source of macroscopic quantized vortices is therefore required, not only to initiate the turbulence, but also to keep the vortex tangle alive. It is demonstrated that a streamwise-pinned, remanent vortex at the channel inlet can act as the fluid dynamical analog of a phase-slip center, injecting vortex filaments into the flow at a steady rate. Several such vortex mills in tandem are sufficient to initiate and sustain the turbulent state.
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  • Superfluid properties of {sup 4}He adsorbed in nanometer-size channels have been studied using torsional oscillators for several channel diameters ranging from 1.5 to 4.7 nm. Clear evidence that {sup 4}He exhibits superfluidity in channels larger than 1.8 nm is obtained. The superfluid transition in channels larger than 2.8 nm is well understood in terms of the finite-size Kosterlitz-Thouless transition, where the vortex unbinding mechanism plays an essential role. This vortex mechanism, however, should break down for channels narrower than the vortex core size (2.5{+-}1.2 nm). Indeed, features that are not expected on the basis of the finite-size Kosterlitz-Thouless theory aremore » observed for channels smaller than 2.2 nm: strong suppression of the observed superfluid density and disappearance of the dissipation peak associated with the diffusive motion of the vortices.« less