INVESTIGADORES
JEZEK Dora Marta
artículos
Título:
Friction force on a vortex due to the scattering of superfluid excitations in helium II
Autor/es:
H. M. CATALDO AND D. M. JEZEK
Revista:
PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS
Editorial:
The American Physical Society
Referencias:
Año: 2002 vol. 65 p. 1845231 - 1845237
ISSN:
0163-1829
Resumen:
The longitudinal friction acting on a vortex line in superfluid 4He is investigated within a simple model
based on the analogy between such vortex dynamics and that of the quantal Brownian motion of a charged
point particle in a uniform magnetic field. The scattering of superfluid quasiparticle excitations by the vortex
stems from a translationally invariant interaction potential which, expanded to first order in the vortex velocity
operator, gives rise to vortex transitions between nearest Landau levels. The corresponding friction coefficient
is shown to be, in the limit of elastic scattering ~vanishing cyclotron frequency!, equivalent to that arising from
the Iordanskii formula. Proposing a simple functional form for the scattering amplitude, with only one adjustable
parameter whose value is set in order to get agreement to the Iordanskii result for phonons, an excellent
agreement is also found with the values derived from experimental data up to temperatures about 1.5 K. Finite
values of the cyclotron frequency arising from recent theories are shown to yield similar results. The incidence
of vortex-induced quasiparticle transitions on the friction process is estimated to be, in the roton dominated
regime, about 50% of the value of the friction coefficient, ;8% of which corresponds to rotonphonon
transitions and ;42% to roton R1$R2 ones.4He is investigated within a simple model
based on the analogy between such vortex dynamics and that of the quantal Brownian motion of a charged
point particle in a uniform magnetic field. The scattering of superfluid quasiparticle excitations by the vortex
stems from a translationally invariant interaction potential which, expanded to first order in the vortex velocity
operator, gives rise to vortex transitions between nearest Landau levels. The corresponding friction coefficient
is shown to be, in the limit of elastic scattering ~vanishing cyclotron frequency!, equivalent to that arising from
the Iordanskii formula. Proposing a simple functional form for the scattering amplitude, with only one adjustable
parameter whose value is set in order to get agreement to the Iordanskii result for phonons, an excellent
agreement is also found with the values derived from experimental data up to temperatures about 1.5 K. Finite
values of the cyclotron frequency arising from recent theories are shown to yield similar results. The incidence
of vortex-induced quasiparticle transitions on the friction process is estimated to be, in the roton dominated
regime, about 50% of the value of the friction coefficient, ;8% of which corresponds to rotonphonon
transitions and ;42% to roton R1$R2 ones.~vanishing cyclotron frequency!, equivalent to that arising from
the Iordanskii formula. Proposing a simple functional form for the scattering amplitude, with only one adjustable
parameter whose value is set in order to get agreement to the Iordanskii result for phonons, an excellent
agreement is also found with the values derived from experimental data up to temperatures about 1.5 K. Finite
values of the cyclotron frequency arising from recent theories are shown to yield similar results. The incidence
of vortex-induced quasiparticle transitions on the friction process is estimated to be, in the roton dominated
regime, about 50% of the value of the friction coefficient, ;8% of which corresponds to rotonphonon
transitions and ;42% to roton R1$R2 ones.;8% of which corresponds to rotonphonon
transitions and ;42% to roton R1$R2 ones.;42% to roton R1$R2 ones.