3,493 research outputs found
Magneto-Acoustic Spectroscopy in Superfluid 3He-B
We have used the recently discovered acoustic Faraday effect in superfluid
3He to perform high resolution spectroscopy of an excited state of the
superfluid condensate. With acoustic cavity interferometry we measure the
rotation of the plane of polarization of a transverse sound wave propagating in
the direction of magnetic field from which we determine the Zeeman energy of
the excited state. We interpret the Lande g-factor, combined with the
zero-field energies of the state, using the theory of Sauls and Serene to
calculate the strength of f -wave interactions in 3He.Comment: 4 pages, 5 figures, submitted to PRL, Aug 30th, 200
Hartree-Fock calculations of a finite inhomogeneous quantum wire
We use the Hartree-Fock method to study an interacting one-dimensional
electron system on a finite wire, partially depleted at the center by a smooth
potential barrier. A uniform one-Tesla Zeeman field is applied throughout the
system. We find that with the increase in the potential barrier, the low
density electrons under it go from a non-magnetic state to an antiferromagnetic
state, and then to a state with a well-localized spin-aligned region isolated
by two antiferromagnetic regions from the high density leads. At this final
stage, in response to a continuously increasing barrier potential, the system
undergoes a series of abrupt density changes, corresponding to the successive
expulsion of a single electron from the spin-aligned region under the barrier.
Motivated by the recent momentum-resolved tunneling experiments in a parallel
wire geometry, we also compute the momentum resolved tunneling matrix elements.
Our calculations suggest that the eigenstates being expelled are spatially
localized, consistent with the experimental observations. However, additional
mechanisms are needed to account for the experimentally observed large spectral
weight at near in the tunneling matrix elements.Comment: 10 pages, 14 figure
Nonlinear field-dependence and f-wave interactions in superfluid 3He
We present results of transverse acoustics studies in superfluid ^{3}He-B at
fields up to 0.11 T. Using acoustic cavity interferometry, we observe the
Acoustic Faraday Effect for a transverse sound wave propagating along the
magnetic field, and we measure Faraday rotations of the polarization as large
as 1710^{\circ}. We use these results to determine the Zeeman splitting of the
Imaginary Squashing mode, an order parameter collective mode with total angular
momentum J=2. We show that the pairing interaction in the f-wave channel is
attractive at a pressure of P=6 bar. We also report nonlinear field dependence
of the Faraday rotation at frequencies substantially above the mode frequency
not accounted for in the theory of the transverse acoustic dispersion relation
formulated for frequencies near the mode. Consequently, we have identified the
region of validity of the theory allowing us to make corrections to the
analysis of Faraday rotation experiments performed in earlier work.Comment: 7 pages, 5 figure
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