5,113 research outputs found
Can the QCD Effective Charge Be Symmetrical in the Euclidean and the Minkowskian Regions?
We study a possible symmetrical behavior of the effective charges defined in
the Euclidean and Minkowskian regions and prove that such symmetry is
inconsistent with the causality principle.Comment: 5 pages, REVTe
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Capitalizing On Diversity: Interpersonal Congruence In Small Work Groups
We examine interpersonal congruence, the degree to which group members see others in the group as others see themselves, as a moderator of the relationship between diversity and group effectiveness. A longitudinal study of 83 work groups revealed that diversity tended to improve creative task performance in groups with high interpersonal congruence, whereas diversity undermined the performance of groups with low interpersonal congruence. This interaction effect also emerged on measures of social integration, group identification, and relationship conflict. By eliciting self-verifying appraisals, members of some groups achieved enough interpersonal congruence during their first ten minutes of interaction to benefit their group outcomes four months later. In contrast to theories of social categorization, the interpersonal congruence approach suggests that group members can achieve harmonious and effective work processes by expressing rather than suppressing the characteristics that make them unique.Managemen
Investigating the Impact of Global Positioning System Evidence
The continued amalgamation of Global Positioning Systems (GPS) into everyday
activities stimulates the idea that these devices will increasingly contribute
evidential importance in digital forensics cases. This study investigates the
extent to which GPS devices are being used in criminal and civil court cases in
the United Kingdom through the inspection of Lexis Nexis, Westlaw, and the
British and Irish Legal Information Institute (BAILII) legal databases. The
research identified 83 cases which involved GPS evidence from within the United
Kingdom and Europe for the time period from 01 June 1993 to 01 June 2013. The
initial empirical analysis indicates that GPS evidence in court cases is rising
over time and the majority of those court cases are criminal cases.Comment: This article was published at:
http://www.hicss.hawaii.edu/hicss_48/apahome48.ht
Casimir Energies and Pressures for -function Potentials
The Casimir energies and pressures for a massless scalar field associated
with -function potentials in 1+1 and 3+1 dimensions are calculated. For
parallel plane surfaces, the results are finite, coincide with the pressures
associated with Dirichlet planes in the limit of strong coupling, and for weak
coupling do not possess a power-series expansion in 1+1 dimension. The relation
between Casimir energies and Casimir pressures is clarified,and the former are
shown to involve surface terms. The Casimir energy for a -function
spherical shell in 3+1 dimensions has an expression that reduces to the
familiar result for a Dirichlet shell in the strong-coupling limit. However,
the Casimir energy for finite coupling possesses a logarithmic divergence first
appearing in third order in the weak-coupling expansion, which seems
unremovable. The corresponding energies and pressures for a derivative of a
-function potential for the same spherical geometry generalizes the TM
contributions of electrodynamics. Cancellation of divergences can occur between
the TE (-function) and TM (derivative of -function) Casimir
energies. These results clarify recent discussions in the literature.Comment: 16 pages, 1 eps figure, uses REVTeX
Casimir energy, dispersion, and the Lifshitz formula
Despite suggestions to the contrary, we show in this paper that the usual
dispersive form of the electromagnetic energy must be used to derive the
Lifshitz force between parallel dielectric media. This conclusion follows from
the general form of the quantum vacuum energy, which is the basis of the
multiple-scattering formalism. As an illustration, we explicitly derive the
Lifshitz formula for the interaction between parallel dielectric semispaces,
including dispersion, starting from the expression for the total energy of the
system. The issues of constancy of the energy between parallel plates and of
the observability of electrostrictive forces are briefly addressed.Comment: 11 pages, no figure
Spectral representation of the effective dielectric constant of graded composites
We generalize the Bergman-Milton spectral representation, originally derived
for a two-component composite, to extract the spectral density function for the
effective dielectric constant of a graded composite. This work has been
motivated by a recent study of the optical absorption spectrum of a graded
metallic film [Applied Physics Letters, 85, 94 (2004)] in which a broad
surface-plasmon absorption band has been shown to be responsible for enhanced
nonlinear optical response as well as an attractive figure of merit. It turns
out that, unlike in the case of homogeneous constituent components, the
characteristic function of a graded composite is a continuous function because
of the continuous variation of the dielectric function within the constituent
components. Analytic generalization to three dimensional graded composites is
discussed, and numerical calculations of multilayered composites are given as a
simple application.Comment: Physical Review E, submitted for publication
Casimir bag energy in the stochastic approximation to the pure QCD vacuum
We study the Casimir contribution to the bag energy coming from gluon field
fluctuations, within the context of the stochastic vacuum model (SVM) of pure
QCD. After formulating the problem in terms of the generating functional of
field strength cumulants, we argue that the resulting predictions about the
Casimir energy are compatible with the phenomenologically required bag energy
term.Comment: 16 page
Statistical-mechanical theory of the overall magnetic properties of mesocrystals
The mesocrystal showing both electrorheological and magnetorheological
effects is called electro-magnetorheological (EMR) solids. Prediction of the
overall magnetic properties of the EMR solids is a challenging task due to the
coexistence of the uniaxially anisotropic behavior and structural transition as
well as long-range interaction between the suspended particles. To consider the
uniaxial anisotropy effect, we present an anisotropic Kirkwood-Fr\"{o}hlich
equation for calculating the effective permeabilities by adopting an explicit
characteristic spheroid rather than a characteristic sphere used in the
derivation of the usual Kirkwood-Fr\"{o}hlich equation. Further, by applying an
Ewald-Kornfeld formulation we are able to investigate the effective
permeability by including the structural transition and long-range interaction
explicitly. Our theory can reduce to the usual Kirkwood-Fr\"{o}hlich equation
and Onsager equation naturally. To this end, the numerical simulation shows the
validity of monitoring the structure of EMR solids by detecting their effective
permeabilities.Comment: 14 pages, 1 figur
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