10,010 research outputs found
Vulnerability to future dependence among former AFDC mothers
This study analyzes short-run AFDC recidivism among mother- only families. Findings suggest that a sizable minority of former AFDC recipients return to AFDC rapidly. Those most likely to return to AFDC are those switching jobs, those moving to publichousing, those adding children, and those not getting regular child support payments. The results also suggest that wages are better predictors of staying off AFDC than are alternative measures of success in the labor market.
Density functional theory of the trapped Fermi gas in the unitary regime
We investigate a density-functional theory (DFT) approach for an unpolarized
trapped dilute Fermi gas in the unitary limit . A reformulation of the recent
work of T. Papenbrock [Phys. Rev. A, {\bf 72}, 041602(R) (2005)] in the
language of fractional exclusion statistics allows us to obtain an estimate of
the universal factor, , in three dimensions (3D), in addition to
providing a systematic treatment of finite- corrections. We show that in 3D,
finite- corrections lead to unphysical values for , thereby
suggesting that a simple DFT applied to a small number of particles may not be
suitable in 3D. We then perform an analogous calculation for the
two-dimensional (2D) system in the infinite-scattering length regime, and
obtain a value of . Owing to the unique properties of the
Thomas-Fermi energy density-functional in 2D our result, in contrast to 3D, is
{\em exact} and therefore requires no finite- corrections
Bulk Spin-Hall Effect
We show that a two-dimensional spin-orbit-coupled system in the presence of a
charge/spin-density wave with a wave-vector perpendicular to an applied
electric field supports bulk manifestations of the direct/inverse spin-Hall
effect. We develop a theory of this phenomenon in the framework of the spin
diffusion equation formalism and show that, due to the inhomogeneity created by
a spin-grating, an anomalous bulk charge-density wave is induced away from
sample boundaries. The optimal conditions for the observation of the effect are
determined. The main experimental manifestation of the bulk spin-Hall effect,
the induced charge/spin-density-wave, is characterized by a pi/2-phase shift
relative to the initial non-homogeneous spin/charge-polarization profile and
has a non-monotonic time-varying amplitude.Comment: 4 pages, 4 figure
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