Searching and organizing images across languages

With the continual growth of users on the Web from a wide range of countries, supporting such users in their search of cultural heritage collections will grow in importance. In the next few years, the growth areas of Internet users will come from the Indian sub-continent and China. Consequently, if holders of cultural heritage collections wish their content to be viewable by the full range of users coming to the Internet, the range of languages that they need to support will have to grow. This paper will present recent work conducted at the University of Sheffield (and now being implemented in BRICKS) on how to use automatic translation to provide search and organisation facilities for a historical image search engine. The system allows users to search for images in seven different languages, providing means for the user to examine translated image captions and browse retrieved images organised by categories written in their native language

Harmonic coordinates in the string and membrane equations

In this note, we first show that the solutions to Cauchy problems for two versions of relativistic string and membrane equations are diffeomorphic. Then we investigate the coordinates transformation presented in Ref. [9] (see (2.20) in Ref. [9]) which plays an important role in the study on the dynamics of the motion of string in Minkowski space. This kind of transformed coordinates are harmonic coordinates, and the nonlinear relativistic string equations can be straightforwardly simplified into linear wave equations under this transformation

One-side forward-backward asymmetry at the LHC

Forward-backward asymmetry $A_{\rm FB}$ is an essential observable to study the nature of coupling in the standard model and physics beyond the standard model, as shown at LEP and Tevatron. As a proton-proton collider, the LHC does not have the preferred direction contrary to her counterpart, namely, LEP and Tevatron. Therefore $A_{\rm FB}$ is not applicable at the LHC. However for the proton the momentum of valence quark is usually larger than that of the sea quark. Utilizing this feature we have defined a so-called one-side forward-backward asymmetry $A_{\rm OFB}$ for the top quark pair production at LHC in the previous work. In this paper we extend our studies to the charged leptons and bottom quarks as the final states. Our numerical results show that at the LHC $A_{\rm OFB}$ can be utilized to study the nature of the couplings once enough events are collected.Comment: 19 pages, 7 figures, 1 table, published versio

Quasiparticle Interference on the Surface of the Topological Insulator Bi2_2Te3_3

The quasiparticle interference of the spectroscopic imaging scanning tunneling microscopy has been investigated for the surface states of the large gap topological insulator Bi$_2$Te$_3$ through the T-matrix formalism. Both the scalar potential scattering and the spin-orbit scattering on the warped hexagonal isoenergy contour are considered. While backscatterings are forbidden by time-reversal symmetry, other scatterings are allowed and exhibit strong dependence on the spin configurations of the eigenfunctions at k points over the isoenergy contour. The characteristic scattering wavevectors found in our analysis agree well with recent experiment results.Comment: 5 pages, 2 figures, Some typos are correcte

Plaquette Ordered Phase and Quantum Phase Diagram in the Spin-1/2 J1-J2 Square Heisenberg Model

We study the spin-1/2 Heisenberg model on the square lattice with first- and second-neighbor antiferromagnetic interactions J1 and J2, which possesses a nonmagnetic region that has been debated for many years and might realize the interesting Z2 spin liquid. We use the density matrix renormalization group approach with explicit implementation of SU(2) spin rotation symmetry and study the model accurately on open cylinders with different boundary conditions. With increasing J2, we find a Neel phase, a plaquette valence-bond (PVB) phase with a finite spin gap, and a possible spin liquid in a small region of J2 between these two phases. From the finite-size scaling of the magnetic order parameter, we estimate that the Neel order vanishes at J2/J1~0.44. For 0.5<J2/J1<0.61, we find dimer correlations and PVB textures whose decay lengths grow strongly with increasing system width, consistent with a long-range PVB order in the two-dimensional limit. The dimer-dimer correlations reveal the s-wave character of the PVB order. For 0.44<J2/J1<0.5, spin order, dimer order, and spin gap are small on finite-size systems and appear to scale to zero with increasing system width, which is consistent with a possible gapless SL or a near-critical behavior. We compare and contrast our results with earlier numerical studies.Comment: 11 pages, 17 figures, and 1 tabl

A Weighted Moving Average Process for Forecasting

The object of the present study is to propose a forecasting model for a nonstationary stochastic realization. The subject model is based on modifying a given time series into a new k-time moving average time series to begin the development of the model. The study is based on the autoregressive integrated moving average process along with its analytical constrains. The analytical procedure of the proposed model is given. A stock XYZ selected from the Fortune 500 list of companies and its daily closing price constitute the time series. Both the classical and proposed forecasting models were developed and a comparison of the accuracy of their responses is given

A Weighted Moving Average Process for Forcasting

A forecasting model for a nonstationary stochastic realization is proposed based on modifying a given time series into a new k-time moving average time series. The study is based on the autoregressive integrated moving average process along with its analytical constrains. The analytical procedure of the proposed model is given. A stock XYZ selected from the Fortune 500 list of companies and its daily closing price constitute the time series. Both the classical and proposed forecasting models were developed and a comparison of the accuracy of their responses is given

SO(5) Superconductors in a Zeeman Magnetic Field

The generic symmetry of a system under a uniform Zeeman magnetic field is U(1) x U(1). However, we show that SO(5) models in the presence of a finite chemical potential and a finite Zeeman magnetic field can have a exact SU(2) x U(1) symmetry. This principle can be used to test SO(5) symmetry at any doping level

Nondiffusive spin dynamics in a two-dimensional electron gas

We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs=GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wave vector range from zero to 6 x 104 cm-1. We find that the spin polarization lifetime is maximal at a nonzero wave vector, in contrast with expectations based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit couplin