26,435 research outputs found
Spectroscopic signatures of the Larkin-Ovchinnikov state in the conductance characteristics of a normal-metal/superconductor junction
Using a discrete-lattice approach, we calculate the conductance spectra
between a normal metal and an s-wave Larkin-Ovchinnikov (LO) superconductor,
with the junction interface oriented {\em along} the direction of the
order-parameter (OP) modulation. The OP sign reversal across one single nodal
line can induce a sizable number of zero-energy Andreev bound states around the
nodal line, and a hybridized midgap-states band is formed amid a
momentum-dependent gap as a result of the periodic array of nodal lines in the
LO state. This band-in-gap structure and its anisotropic properties give rise
to distinctive features in both the point-contact and tunneling spectra as
compared with the BCS and Fulde-Ferrell cases. These spectroscopic features can
serve as distinguishing signatures of the LO state.Comment: 8 pages, 5 figures; version as publishe
Topology of Entanglement in Multipartite States with Translational Invariance
The topology of entanglement in multipartite states with translational
invariance is discussed in this article. Two global features are foundby which
one can distinguish distinct states. These are the cyclic unit and the
quantised geometric phase. Furthermore the topology is indicated by the
fractional spin. Finally a scheme is presented for preparation of these types
of states in spin chain systems, in which the degeneracy of the energy levels
characterises the robustness of the states with translational invariance.Comment: major revision. accepted by EPJ
Pairwise Entanglement and Geometric Phase in -Dimensional Free-Fermion Lattice Systems
The pairwise entanglement, measured by concurrence and geometric phase in
-dimensional free-fermion lattice systems have been studied for the
ground state in this paper. Their derivation with respect to the external
parameter show the singularity closed to the phase transition points, and can
be used to detect the phase transition in this model. Furthermore our studies
show for the free-fermion model that both concurrence and geometric phase shows
the intimate connection with the correlation functions. The possible relation
between concurrence and geometric phase has been also discussed.Comment: 7+pages, EPJD styl
Continuous volumetric imaging via an optical phase-locked ultrasound lens
In vivo imaging at high spatiotemporal resolution is key to the understanding of complex biological systems. We integrated an optical phase-locked ultrasound lens into a two-photon fluorescence microscope and achieved microsecond-scale axial scanning, thus enabling volumetric imaging at tens of hertz. We applied this system to multicolor volumetric imaging of processes sensitive to motion artifacts, including calcium dynamics in behaving mouse brain and transient morphology changes and trafficking of immune cells
Electronic Structures of Fe_x$Si Probed by Photoemission Spectroscopy
The electronic structures of the Heusler type compounds Fe_x$Si in
the concentration range between x = 0 and x = 1 have been probed by
photoemission spectroscopy (PES). The observed shift of Si 2p core- level and
the main valence band structres indicate a chemical potential shift to higher
energy with increasing x. It is also clarified that the density of state at
Fermi edge is owing to the collaboration of V 3d and Fe 3d derived states.
Besides the decrease of the spectral intensity near Fermi edge with increasing
x suggests the formation of pseudo gap at large x.Comment: 4 pages, 5 figures, 5 reference
Cessation of X-ray Pulsation of GX 1+4
We report results from our weekly monitoring campaign on the X-ray pulsar GX
1+4 with the {\em Rossi X-ray Timing Explorer} satellite. The spin-down trend
of GX 1+4 was continuing, with the pulsar being at its longest period ever
measured (about 138.7 s). At the late stage of the campaign, the source entered
an extended faint state, when its X-ray (2-60 keV) flux decreased significantly
to an average level of . It was
highly variable in the faint state; the flux dropped to as low as . In several observations during this
period, the X-ray pulsation became undetectable. We can, therefore, conclude
conservatively that the pulsed fraction, which is normally 70%
(peak-to-peak), must have decreased drastically in those cases. This is very
similar to what was observed of GX 1+4 in 1996 when it became similarly faint
in X-ray. In fact, the flux at which the cessation of X-ray pulsation first
occurred is nearly the same as it was in 1996. We suggest that we have, once
again, observed the propeller effect in GX 1+4, a phenomenon that is predicted
by theoretical models of accreting X-ray pulsars.Comment: 13 pages, 9 figures (available at
http://www.physics.purdue.edu/~cui/ftp/cuifigs.tar.gz). To appear in Ap
Transport and structural study of pressure-induced magnetic states in Nd0.55Sr0.45MnO3 and Nd0.5Sr0.5MnO3
Pressure effects on the electron transport and structure of Nd1-xSrxMnO3 (x =
0.45, 0.5) were investigated in the range from ambient to ~6 GPa. In
Nd0.55Sr0.45MnO3, the low-temperature ferromagnetic metallic state is
suppressed and a low temperature insulating state is induced by pressure. In
Nd0.5Sr0.5MnO3, the CE-type antiferromagnetic charge-ordering state is
suppressed by pressure. Under pressure, both samples have a similar electron
transport behavior although their ambient ground states are much different. It
is surmised that pressure induces an A-type antiferromagnetic state at low
temperature in both compounds
An assessment of wetland nature reserves and the protection of China’s vertebrate diversity
Evaluación de los humedales declarados reserva natural y protección de la diversidad de vertebrados de China
Se evaluaron las reservas naturales existentes en China y se estudió la distribución de los cuatro taxones de vertebrados terrestres endémicos y amenazados, que comprenden los reptiles, los anfibios, las aves y los mamíferos. Con vistas a determinar la riqueza de las especies, se combinó la evaluación anterior de los 148 humedales declarados reserva natural con la lista de los vertebrados endémicos y amenazados elaborada por el gobierno. Dicha riqueza de especies se clasificó en tres categorías: alta, media y baja mediante un análisis factorial y se seleccionaron 31 ecosistemas de humedales como zonas de alta protección. Asimismo, se analizó la relación existente entre las especies amenazadas y las endémicas en las reservas, y se observó que ambos modelos de riqueza eran parecidos. Se espera que, sobre la base del estudio de la riqueza, se pueda crear un sistema de clasificación de las reservas naturales, con su gestión correspondiente, con el objetivo de proteger la diversidad de las especies en China.We assessed all 148 wetland nature reserves in China and the distribution of the four taxa of endemic and threatened terrestrial vertebrates, reptiles, amphibians, birds and mammals. Assessment of the wetland nature reserves was combined with the governmental list of the endemic and threatened vertebrates to identify the richness of the species. Species richness was scored as high, medium or low using a factor analysis method, and 31 wetland ecosystems were marked as high protection areas. The relationship between the threatened species and the endemic species in the reserves was also analyzed. We found that both richness patterns were similar. Based on the richness study, a nature reserve classification system with correspondingEvaluación de los humedales declarados reserva natural y protección de la diversidad de vertebrados de China
Se evaluaron las reservas naturales existentes en China y se estudió la distribución de los cuatro taxones de vertebrados terrestres endémicos y amenazados, que comprenden los reptiles, los anfibios, las aves y los mamíferos. Con vistas a determinar la riqueza de las especies, se combinó la evaluación anterior de los 148 humedales declarados reserva natural con la lista de los vertebrados endémicos y amenazados elaborada por el gobierno. Dicha riqueza de especies se clasificó en tres categorías: alta, media y baja mediante un análisis factorial y se seleccionaron 31 ecosistemas de humedales como zonas de alta protección. Asimismo, se analizó la relación existente entre las especies amenazadas y las endémicas en las reservas, y se observó que ambos modelos de riqueza eran parecidos. Se espera que, sobre la base del estudio de la riqueza, se pueda crear un sistema de clasificación de las reservas naturales, con su gestión correspondiente, con el objetivo de proteger la diversidad de las especies en China
Coherent Single Charge Transport in Molecular-Scale Silicon Nanowire Transistors
We report low-temperature electrical transport studies of molecule-scale
silicon nanowires. Individual nanowires exhibit well-defined Coulomb blockade
oscillations characteristic of charge addition to a single nanostructure with
length scales up to at least 400 nm. Further studies demonstrate coherent
charge transport through discrete single particle quantum levels extending the
whole device, and show that the ground state spin configuration follows the
Lieb-Mattis theorem. In addition, depletion of the nanowires suggests that
phase coherent single-dot characteristics are accessible in a regime where
correlations are strong.Comment: 4 pages and 4 figure
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