1,107 research outputs found
Citrullinated fibrinogen shows defects in FPA and FPB release and fibrin polymerization catalyzed by thrombin
ArticleClinica Chimica Acta. 401(1-2):119-123 (2009)journal articl
Microscopic Theory of Skyrmions in Quantum Hall Ferromagnets
We present a microscopic theory of skyrmions in the monolayer quantum Hall
ferromagnet. It is a peculiar feature of the system that the number density and
the spin density are entangled intrinsically as dictated by the W
algebra. The skyrmion and antiskyrmion states are constructed as W-rotated states of the hole-excited and electron-excited states,
respectively. They are spin textures accompanied with density modulation that
decreases the Coulomb energy. We calculate their excitation energy as a
function of the Zeeman gap and compared the result with experimental data.Comment: 15 pages (to be published in PRB
Spin gap in the 2D electron system of GaAs/AlGaAs single heterojunctions in weak magnetic fields
We study the interaction-enhanced spin gaps in the two-dimensional electron
gas confined in GaAs/AlGaAs single heterojunctions subjected to weak magnetic
fields. The values are obtained from the chemical potential jumps measured by
magnetocapacitance. The gap increase with parallel magnetic field indicates
that the lowest-lying charged excitations are accompanied with a single spin
flip at the odd-integer filling factor nu=1 and nu=3, in disagreement with the
concept of skyrmions.Comment: as publishe
Spectral variability in Cygnus X-3
We model the broad-band X-ray spectrum of Cyg X-3 in all states displayed by
this source as observed by the Rossi X-ray Timing Explorer. From our models, we
derive for the first time unabsorbed spectral shapes and luminosities for the
full range of spectral states. We interpret the unabsorbed spectra in terms of
Comptonization by a hybrid electron distribution and strong Compton reflection.
We study the spectral evolution and compare with other black hole as well as
neutron star sources. We show that a neutron star accretor is not consistent
with the spectral evolution as a function of Ledd and especially not with the
transition to a hard state. Our results point to the compact object in Cyg X-3
being a massive, ~30 Msun black hole.Comment: 14 pages, 9 figures, accepted for publication in MNRA
Collective modes of CP(3) Skyrmion crystals in quantum Hall ferromagnets
The two-dimensional electron gas in a bilayer quantum Hall system can sustain
an interlayer coherence at filling factor nu=1 even in the absence of tunneling
between the layers. This system has low-energy charged excitations which may
carry textures in real spin or pseudospin. Away from filling factor nu =1 a
finite density of these is present in the ground state of the 2DEG and forms a
crystal. Depending on the relative size of the various energy scales, such as
tunneling (Delta_SAS), Zeeman coupling (Delta_Z) or electrical bias (Delta_b),
these textured crystal states can involve spin, pseudospin, or both
intertwined. In this article, we present a comprehensive numerical study of the
collective excitations of these textured crystals using the GRPA. For the pure
spin case, at finite Zeeman coupling the state is a Skyrmion crystal with a
gapless phonon mode, and a separate Goldstone mode that arises from a broken
U(1) symmetry. At zero Zeeman coupling, we demonstrate that the constituent
Skyrmions break up, and the resulting state is a meron crystal with 4 gapless
modes. In contrast, a pure pseudospin Skyrme crystal at finite tunneling has
only the phonon mode. For Delta_SAS=0, the state evolves into a meron crystal
and supports an extra gapless U(1) mode in addition to the phonon. For a CP(3)
Skyrmion crystal, we find a U(1) gapless mode in the presence of the
symmetry-breaking fields. In addition, a second mode with a very small gap is
present in the spectrum.Comment: 16 pages and 12 eps figure
Big Bang Nucleosynthesis and Lepton Number Asymmetry in the Universe
Recently it is reported that there is the discrepancy between big bang
nucleosynthesis theory and observations (BBN crisis). We show that BBN
predictions agree with the primordial abundances of light elements, He4, D, He3
and Li7 inferred from the observational data if an electron neutrino has a net
chemical potential xi_{nu_e} due to lepton asymmetry. We estimate that
xi_{nu_e} = 0.043^{+0.040}_{-0.040} (95% C.L.) and Omega_bh^2 =
0.015^{+0.006}_{-0.003} (95% C.L.).Comment: 10 pages, using AAS LATEX and three postscript figure
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