1,968 research outputs found
Cross-orientation transfer of adaptation for facial identity is asymmetric: A study using contrast-based recognition thresholds
AbstractRecent studies suggest that adaptation effects for face shape and gender transfer from upright to inverted faces more than the reverse. We investigated whether a similar asymmetry occurred for face identity, using a recently developed adaptation method based on contrast-recognition thresholds. When adapting and test stimuli shared the same orientation, aftereffects were similar for upright and inverted faces. When orientation differed, there was significant transfer of aftereffects from upright adapting to inverted test faces, but none from inverted to upright faces. We show that asymmetric cross-orientation transfer of face aftereffects generalize across two distinct face adaptation paradigms: the previously used perceptual-bias methodology and the recently introduced contrast-threshold based adaptation paradigm. These results also represent a generalization from aftereffects for face shape and gender to aftereffects for face identity. While these results are consistent with the dual-mode hypothesis, they can also be accounted for by a single population of units of varying orientation selectivity
Ordering and finite-size effects in the dynamics of one-dimensional transient patterns
We introduce and analyze a general one-dimensional model for the description
of transient patterns which occur in the evolution between two spatially
homogeneous states. This phenomenon occurs, for example, during the
Freedericksz transition in nematic liquid crystals.The dynamics leads to the
emergence of finite domains which are locally periodic and independent of each
other. This picture is substantiated by a finite-size scaling law for the
structure factor. The mechanism of evolution towards the final homogeneous
state is by local roll destruction and associated reduction of local
wavenumber. The scaling law breaks down for systems of size comparable to the
size of the locally periodic domains. For systems of this size or smaller, an
apparent nonlinear selection of a global wavelength holds, giving rise to long
lived periodic configurations which do not occur for large systems. We also
make explicit the unsuitability of a description of transient pattern dynamics
in terms of a few Fourier mode amplitudes, even for small systems with a few
linearly unstable modes.Comment: 18 pages (REVTEX) + 10 postscript figures appende
Scheme for the preparation of the multi-particle entanglement in cavity QED
Here we present a quantum electrodynamics (QED) model involving a
large-detuned single-mode cavity field and identical two-level atoms. One
of its applications for the preparation of the multi-particle states is
analyzed. In addition to the Greenberger-Horne-Zeilinger (GHZ) state, the W
class states can also be generated in this scheme. The further analysis for the
experiment of the model of case is also presented by considering the
possible three-atom collision.Comment: 5 Pages, 1 Figure. Minor change
Two qubits of a W state violate Bell's inequality beyond Cirel'son's bound
It is shown that the correlations between two qubits selected from a trio
prepared in a W state violate the Clauser-Horne-Shimony-Holt inequality more
than the correlations between two qubits in any quantum state. Such a violation
beyond Cirel'son's bound is smaller than the one achieved by two qubits
selected from a trio in a Greenberger-Horne-Zeilinger state [A. Cabello, Phys.
Rev. Lett. 88, 060403 (2002)]. However, it has the advantage that all local
observers can know from their own measurements whether their qubits belongs or
not to the selected pair.Comment: REVTeX4, 5 page
Scintillation and charge extraction from the tracks of energetic electrons in superfluid helium-4
An energetic electron passing through liquid helium causes ionization along
its track. The ionized electrons quickly recombine with the resulting positive
ions, which leads to the production of prompt scintillation light. By applying
appropriate electric fields, some of the ionized electrons can be separated
from their parent ions. The fraction of the ionized electrons extracted in a
given applied field depends on the separation distance between the electrons
and the ions. We report the determination of the mean electron-ion separation
distance for charge pairs produced along the tracks of beta particles in
superfluid helium at 1.5 K by studying the quenching of the scintillation light
under applied electric fields. Knowledge of this mean separation parameter will
aid in the design of particle detectors that use superfluid helium as a target
material.Comment: 10 pages, 8 figure
Efficient quantum key distribution scheme with nonmaximally entangled states
We propose an efficient quantum key distribution scheme based on
entanglement. The sender chooses pairs of photons in one of the two equivalent
nonmaximally entangled states randomly, and sends a sequence of photons from
each pair to the receiver. They choose from the various bases independently but
with substantially different probabilities, thus reducing the fraction of
discarded data, and a significant gain in efficiency is achieved. We then show
that such a refined data analysis guarantees the security of our scheme against
a biased eavesdropping strategy.Comment: 5 Pages, No Figur
OL-085 A candidate genes study for the association of host single nucleotide polymorphisms with liver cirrhosis risk in Chinese hepatitis B patients
Parameterization and Reconstruction of Quasi Static Universe
We study a possibility of the fate of universe, in which there is neither the
rip singularity, which results in the disintegration of bound systems, nor the
endless expansion, instead the universe will be quasi static. We discuss the
parameterization of the corresponding evolution and the reconstruction of the
scalar field model. We find, with the parameterization consistent with the
current observation, that the current universe might arrive at a quasi static
phase after less than 20Gyr.Comment: minor changes and Refs. added, publish in EPJ
Predicted Infrared and Raman Spectra for Neutral Ti_8C_12 Isomers
Using a density-functional based algorithm, the full IR and Raman spectra are
calculated for the neutral Ti_8C_12 cluster assuming geometries of Th, Td, D2d
and C3v symmetry. The Th pentagonal dodecahedron is found to be dynamically
unstable. The calculated properties of the relaxed structure having C3v
symmetry are found to be in excellent agreement with experimental gas phase
infrared results, ionization potential and electron affinity measurements.
Consequently, the results presented may be used as a reference for further
experimental characterization using vibrational spectroscopy.Comment: 6 pages, 5 figures. Physical Review A, 2002 (in press
Parametrization of Born-Infeld Type Phantom Dark Energy Model
Applying the parametrization of dark energy density, we can construct
directly independent-model potentials. In Born-Infeld type phantom dark energy
model, we consider four special parametrization equation of state parameter.
The evolutive behavior of dark energy density with respect to red-shift ,
potentials with respect to and are shown mathematically. Moreover,
we investigate the effect of parameter upon the evolution of the
constructed potential with respect to . These results show that the
evolutive behavior of constructed Born-Infeld type dark energy model is quite
different from those of the other models.Comment: 5 pages, 4 figures, Accepted for publication in Astrophysics & Space
Scienc
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