Large anisotropy in the optical conductivity of YNi2B2C

The optical properties of YNi$_2$B$_2$C are studied by using the first-principles full-potential linearized augmented plane wave (FLAPW) method within the local density approximation. Anisotropic behavior is obtained in the optical conductivity, even though the electronic structure shows 3D character. A large peak in $\sigma_z$ is obtained at 2.4 eV. The anisotropic optical properties are analyzed in terms of interband transitions between energy levels and found that the Ni site plays an important role. The electronic energy loss spectroscopy (EELS) spectra are also calculated to help elucidate the anisotropic properties in this system.Comment: revtex4, 4 pages, 5 figures, to appear in PR

Quenching of Cross Sections in Nucleon Transfer Reactions

Cross sections for proton knockout observed in (e,e'p) reactions are apparently quenched by a factor of ~0.5, an effect attributed to short-range correlations between nucleons. Here we demonstrate that such quenching is not restricted to proton knockout, but a more general phenomenon associated with any nucleon transfer. Measurements of absolute cross sections on a number of targets between 16O and 208Pb were analyzed in a consistent way, with the cross sections reduced to spectroscopic factors through the distorted-wave Born approximation with global optical potentials. Across the 124 cases analyzed here, induced by various proton- and neutron-transfer reactions and with angular momentum transfer l=0-7, the results are consistent with a quenching factor of 0.55. This is an apparently uniform quenching of single-particle motion in the nuclear medium. The effect is seen not only in (d,p) reactions but also in reactions with A=3 and 4 projectiles, when realistic wave functions are used for the projectiles.Comment: 5 pages, 3 figures, accepted to Physical Review Letter

Will Unionism Prosper in Cyber-Space? The Promise of the Internet for Employee Organization

This paper argues that the low cost of information, communication, and interaction on the Web offers trade unions opportunities to improve services and attract members and thus reinvent themselves for the 21st Century. Analyzing current use of the Internet by unions in the United Kingdom and United States, we develop five hypothesis about the impact of the Internet on unions. 1) the Customized Services hypothesis that unions will individualize services; 2) the Cyber-organizing hypothesis that the Web will ease organization and produce virtual minority unions at many non-union firms; 3) the Cyber-democracy hypothesis that the Web will enhance democracy in unions; 4) the Cyber-dispute hypothesis that the Web will become an important space for industrial disputes; and 5) the New Internationalism hypothesis that the Web will strengthen the international labor community. If unions fail to exploit the opportunities on the Web to gain members, we expect other organizations, Internet recruitment sites, specialized advice centers, and the like, to fill the e-union niche.

Shared Modes of Compensation and Firm Performance: UK Evidence

This paper examines the use and consequences of shared compensation plans (profit sharing, profit related pay, SAYE schemes and company stock option plans) in a sample of UK workplaces and firms in the 1990s. The use of these plans has increased over time, in part in response to government programs. The evidence shows that companies and workplaces adopting shared compensation practices have had higher productivity than other firms, but the effects vary among programs, suggesting that the particulars matter a lot in aligning shared compensation and work place activities. Consistent with incentive theory, the evidence also shows that firms and workplaces with shared compensation practices have a higher incidence of shared decision-making / information sharing practices.

Relaxation dynamics of the toric code in contact with a thermal reservoir: Finite-size scaling in a low temperature regime

We present an analysis of the relaxation dynamics of finite-size topological qubits in contact with a thermal bath. Using a continuous-time Monte Carlo method, we explicitly compute the low-temperature nonequilibrium dynamics of the toric code on finite lattices. In contrast to the size-independent bound predicted for the toric code in the thermodynamic limit, we identify a low-temperature regime on finite lattices below a size-dependent crossover temperature with nontrivial finite-size and temperature scaling of the relaxation time. We demonstrate how this nontrivial finite-size scaling is governed by the scaling of topologically nontrivial two-dimensional classical random walks. The transition out of this low-temperature regime defines a dynamical finite-size crossover temperature that scales inversely with the log of the system size, in agreement with a crossover temperature defined from equilibrium properties. We find that both the finite-size and finite-temperature scaling are stronger in the low-temperature regime than above the crossover temperature. Since this finite-temperature scaling competes with the scaling of the robustness to unitary perturbations, this analysis may elucidate the scaling of memory lifetimes of possible physical realizations of topological qubits.Comment: 14 Pages, 13 figure