An adaptive algorithm for n-body field expansions
Weinberg, Martin D.
1998-05-28
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8 records were found.
Experimental results on the absolute magneto-transmission of a series of high
density, high mobility GaAs quantum wells are compared with the predictions of
a recent magnetoplasmon theory for values of the filling factor above 2. We
show that the magnetoplasmon picture can explain the non-linear features
observed in the magnetic field evolution of the cyclotron resonance energies
and of the absorption oscillator strength. This provides experimental evidence
that inter Landau level excitations probed by infrared spectroscopy need to be
considered as many body excitations in terms of magnetoplasmons: this is
especially true when interpreting the oscillator strengths of the cyclotron
transitions.
The quantum Hall effect is investigated in a high-mobility two-dimensional
electron gas on the surface of a cylinder. The novel topology leads to a
spatially varying filling factor along the current path. The resulting
inhomogeneous current-density distribution gives rise to additional features in
the magneto-transport, such as resistance asymmetry and modified longitudinal
resistances. We experimentally demonstrate that the asymmetry relations
satisfied in the integer filling factor regime are valid also in the transition
regime to non-integer filling factors, thereby suggesting a more general form
of these asymmetry relations. A model is developed based on the screening
theory of the integer quantum Hall effect that allows the self-consistent
calculation of the local electron density and thereby the local current density
including ...
Comment: 4 pages, 3 figures
Comment: 4 pages, 4 figures, to be published in Phys. Rev. Lett
Comment: 18 pages, 2 figures, ApJL in press
Kinematic investigations are being increasingly deployed in studies of the lowest mass stars and brown dwarfs to investigate their origins, characterize their atmospheres, and examine the evolution of their physical parameters. This article summarizes the contributions made at the “Kinematics of Very Low Mass Dwarfs” splinter session. Results discussed include analysis of kinematic distributions of M, L, and T dwarfs; theoretical tools for interpreting these distributions; identifications of very low mass halo dwarfs and wide companions to nearby stars; radial velocity variability among young and very cool brown dwarfs; and the search and identification of M dwarfs in young moving groups. A summary of discussion points at the conclusion of the splinter sesseion is also presented.
