429 research outputs found
Revealing Randall-Sundrum Hidden Valleys
We study 5D gauge symmetries in the Randall-Sundrum geometry that are hidden
from the standard model through either small 5D gauge coupling, or through
vanishing quantum numbers for the standard model fields. Geometric warping of
5D gravity creates a TeV scale bridge from the standard model to the hidden
sector gauge fields. We apply these concepts to a revival of the electroweak
axion model, in which the dynamics of Peccei-Quinn symmetry breaking occur at
the TeV scale.Comment: 29 pages, 3 figures, 3 table
Ordering monomial factors of polynomials in the product representation
The numerical construction of polynomials in the product representation (as
used for instance in variants of the multiboson technique) can become
problematic if rounding errors induce an imprecise or even unstable evaluation
of the polynomial. We give criteria to quantify the effects of these rounding
errors on the computation of polynomials approximating the function . We
consider polynomials both in a real variable and in a Hermitian matrix. By
investigating several ordering schemes for the monomials of these polynomials,
we finally demonstrate that there exist orderings of the monomials that keep
rounding errors at a tolerable level.Comment: Latex2e file, 7 figures, 32 page
Four-dimensional Simulation of the Hot Electroweak Phase Transition with the SU(2) Gauge-Higgs Model
We study the finite-temperature phase transition of the four-dimensional
SU(2) gauge-Higgs model for intermediate values of the Higgs boson mass in the
range 50 \lsim m_H \lsim 100GeV on a lattice with the temporal lattice size
. The order of the transition is systematically examined using finite
size scaling methods. Behavior of the interface tension and the latent heat for
an increasing Higgs boson mass is also investigated.Comment: Talk presented at LATTICE96(electroweak), 3 pages of LaTeX, 4
PostScript figure
Light meson decay constants beyond the quenched approximation
We calculate the effects of including dynamical fermion loops in the lattice
QCD estimates of meson decay constants, by extrapolating the results from
negative flavour numbers after a suitable matching of the pion and rho mass.
For moderately light quarks, the values of the decay constants not corrected
for the renormalization constants increase with respect to their quenched
values.Comment: 9 pages, uuencoded PS file, 2 figures include
Pseudofermion observables for static heavy meson decay constants on the lattice
A method based on the Monte Carlo inversion of the Dirac operator on the
lattice provides low noise results for the correlations entering the definition
of the heavy meson decay constant in the static limit. The method is
complementary to the usual method of smeared sources, avoids the systematic
error arising from optimizing the size of the smearing volume and is more
efficient for the values of lattice parameters that we have explored.Comment: 11 pages, uuencoded ps file, 2 figures include
A new simulation algorithm for lattice QCD with dynamical quarks
A previously introduced multi-boson technique for the simulation of QCD with
dynamical quarks is described and some results of first test runs on a
lattice with Wilson quarks and gauge group SU(2) are reported.Comment: 7 pages, postscript file (166 KB
Evaluation available encapsulation materials for low-cost long-life silicon photovoltaic arrays
Experimental evaluation of selected encapsulation designs and materials based on an earlier study which have potential for use in low cost, long-life photovoltaic arrays are reported. The performance of candidate materials and encapsulated cells were evaluated principally for three types of encapsulation designs based on their potentially low materials and processing costs: (1) polymeric coatings, transparent conformal coatings over the cell with a structural-support substrate; (2) polymeric film lamination, cells laminated between two films or sheets of polymeric materials; and (3) glass-covered systems, cells adhesively bonded to a glass cover (superstrate) with a polymeric pottant and a glass or other substrate material. Several other design types, including those utilizing polymer sheet and pottant materials, were also included in the investigation
Solving Lattice QCD systems of equations using mixed precision solvers on GPUs
Modern graphics hardware is designed for highly parallel numerical tasks and
promises significant cost and performance benefits for many scientific
applications. One such application is lattice quantum chromodyamics (lattice
QCD), where the main computational challenge is to efficiently solve the
discretized Dirac equation in the presence of an SU(3) gauge field. Using
NVIDIA's CUDA platform we have implemented a Wilson-Dirac sparse matrix-vector
product that performs at up to 40 Gflops, 135 Gflops and 212 Gflops for double,
single and half precision respectively on NVIDIA's GeForce GTX 280 GPU. We have
developed a new mixed precision approach for Krylov solvers using reliable
updates which allows for full double precision accuracy while using only single
or half precision arithmetic for the bulk of the computation. The resulting
BiCGstab and CG solvers run in excess of 100 Gflops and, in terms of iterations
until convergence, perform better than the usual defect-correction approach for
mixed precision.Comment: 30 pages, 7 figure
Swearing at Work: The Mixed Outcomes of Profanity
We explore the use and misuse of swearing in the workplace. Using a qualitative methodology, we interviewed 52 lawyers, medical doctors and business executives in the UK, France, and the U.S. In contrast to much of the incivility and social norms literatures, we find that male and female business executives, lawyers and doctors of all ages admit to swearing. Further, swearing can lead to positive outcomes at the individual, interpersonal and group levels, including stress-relief, communication-enrichment, and socialization-enhancement. An implication for future scholarship is that âthinking out of the boxâ when exploring emotion related issues can lead to new insights. Practical implications include reconsidering and tolerating incivility under certain conditions. We identified a case in which a negative phenomenon reveals counter-intuitive yet insightful results
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