4,522 research outputs found
Electric Character of Strange Stars
Using the Thomas-Fermi model, we investigated the electric characteristics of
a static non-magnetized strange star without crust in this paper. The exact
solutions of electron number density and electric field above the quark surface
are obtained. These results are useful if we are concerned about physical
processes near the quark matter surfaces of strange stars.Comment: 4 pages, 2 figures, LaTeX, Published in Chinese Physics Letters,
Vol.16, p.77
Low field phase diagram of spin-Hall effect in the mesoscopic regime
When a mesoscopic two dimensional four-terminal Hall cross-bar with Rashba
and/or Dresselhaus spin-orbit interaction (SOI) is subjected to a perpendicular
uniform magnetic field , both integer quantum Hall effect (IQHE) and
mesoscopic spin-Hall effect (MSHE) may exist when disorder strength in the
sample is weak. We have calculated the low field "phase diagram" of MSHE in the
plane for disordered samples in the IQHE regime. For weak disorder,
MSHE conductance and its fluctuations vanish identically
on even numbered IQHE plateaus, they have finite values on those odd numbered
plateaus induced by SOI, and they have values and
on those odd numbered plateaus induced by Zeeman energy. For moderate disorder,
the system crosses over into a regime where both and are
finite. A larger disorder drives the system into a chaotic regime where
while is finite. Finally at large disorder both
and vanish. We present the physics behind this ``phase
diagram".Comment: 4 page, 3 figure
Universal spin-Hall conductance fluctuations in two dimensions
We report a theoretical investigation on spin-Hall conductance fluctuation of
disordered four terminal devices in the presence of Rashba or/and Dresselhaus
spin-orbital interactions in two dimensions. As a function of disorder, the
spin-Hall conductance shows ballistic, diffusive and insulating
transport regimes. For given spin-orbit interactions, a universal spin-Hall
conductance fluctuation (USCF) is found in the diffusive regime. The value of
the USCF depends on the spin-orbit coupling , but is independent of
other system parameters. It is also independent of whether Rashba or
Dresselhaus or both spin-orbital interactions are present. When is
comparable to the hopping energy , the USCF is a universal number . The distribution of crosses over from a Gaussian distribution
in the metallic regime to a non-Gaussian distribution in the insulating regime
as the disorder strength is increased.Comment: to be published in Phys. Rev. Lett., 4 figure
Measurements of diffusion, T 1 and T 2 in one shot by MMME
In this paper, we demonstrate a rapid simultaneous measurement of diffusion constant D, T1 and T2 relaxation times in just two scans. Theoretical standard deviations of D, T1 T2 for a wide range of T1 and T2 were predicted for given sequences with a random experimental error of 3%. By carefully selecting of sequence parameters for samples with different relaxation times, the error propagators in T1, T2, and D can be modified to within 10%
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