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 $n$ 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 $n=2$ 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

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 $z$, potentials with respect to $\phi$ and $z$ are shown mathematically. Moreover, we investigate the effect of parameter $\eta$ upon the evolution of the constructed potential with respect to $z$. 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