34,029 research outputs found
Large anisotropy in the optical conductivity of YNi2B2C
The optical properties of YNiBC 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 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
- …