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Memory Effects in Superfluid Vortex Dynamics

Memory Effects in Superfluid Vortex Dynamics The dissipative dynamics of a vortex line in a superfluid is investigated within the frame of a non-Markovian quantal Brownian motion model. Our starting point is a recently proposed interaction Hamiltonian between the vortex and the superfluid quasiparticle excitations, which is generalized to incorporate the effect of scattering from fermion impurities (3He atoms). Thus, a non-Markovian equation of motion for the mean value of the vortex position operator is derived within a weak-coupling approximation. Such an equation is shown to yield, in the Markovian and elastic scattering limits, a 3He contribution to the longitudinal friction coefficient equivalent to that arising from the Rayfield–Reif formula. Simultaneous Markov and elastic scattering limits are found, however, to be incompatible, since an unexpected breakdown of the Markovian approximation is detected at low cyclotron frequencies. Then, a non-Markovian expression for the longitudinal friction coefficient is derived and computed as a function of temperature and 3He concentration. Such calculations show that cyclotron frequencies within the range 0.01–0.03 ps −1 yield a very good agreement to the longitudinal friction figures computed from the Iordanskii and Rayfield–Reif formulas for pure 4He, up to temperatures near 1 K. A similar performance is found for nonvanishing 3He concentrations, where the comparison is also shown to be very favourable with respect to the available experimental data. Memory effects are shown to be weak and increasing with temperature and concentration. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Low Temperature Physics Springer Journals

Memory Effects in Superfluid Vortex Dynamics

Cataldo, H.; Jezek, D.
Journal of Low Temperature Physics , Volume 136 (4) – Oct 5, 2004
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References (17)

Publisher
Springer Journals
Copyright
Copyright © 2004 by Springer Science+Business Media, Inc.
Subject
Physics; Condensed Matter Physics; Characterization and Evaluation of Materials; Magnetism, Magnetic Materials
ISSN
0022-2291
eISSN
1573-7357
DOI
10.1023/B:JOLT.0000038523.79225.75
Publisher site
See Article on Publisher Site

Abstract

The dissipative dynamics of a vortex line in a superfluid is investigated within the frame of a non-Markovian quantal Brownian motion model. Our starting point is a recently proposed interaction Hamiltonian between the vortex and the superfluid quasiparticle excitations, which is generalized to incorporate the effect of scattering from fermion impurities (3He atoms). Thus, a non-Markovian equation of motion for the mean value of the vortex position operator is derived within a weak-coupling approximation. Such an equation is shown to yield, in the Markovian and elastic scattering limits, a 3He contribution to the longitudinal friction coefficient equivalent to that arising from the Rayfield–Reif formula. Simultaneous Markov and elastic scattering limits are found, however, to be incompatible, since an unexpected breakdown of the Markovian approximation is detected at low cyclotron frequencies. Then, a non-Markovian expression for the longitudinal friction coefficient is derived and computed as a function of temperature and 3He concentration. Such calculations show that cyclotron frequencies within the range 0.01–0.03 ps −1 yield a very good agreement to the longitudinal friction figures computed from the Iordanskii and Rayfield–Reif formulas for pure 4He, up to temperatures near 1 K. A similar performance is found for nonvanishing 3He concentrations, where the comparison is also shown to be very favourable with respect to the available experimental data. Memory effects are shown to be weak and increasing with temperature and concentration.

Journal

Journal of Low Temperature Physics – Springer Journals

Published: Oct 5, 2004

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