1,608 research outputs found
String Tension from Monopoles in SU(2) Lattice Gauge Theory
The axis for Figure 2 was wrong. It has been fixed and the postscript file
replaced (The file was called comp.ps).Comment: (22 pages latex (revtex); 2 figures appended as postscript files -
search for mono.ps and comp.ps. Figures mailed on request--send a note to
[email protected]) Preprint ILL-(TH)-94-#1
Micro-abrasion–corrosion of a Co–Cr/UHMWPE couple in Ringer's solution : an approach to construction of mechanism and synergism maps for application to bio-implants
In studies of tribo-corrosion, the degradation of bio-materials has become of increasing research interest in recent years. This is because, in many cases, the interactions of the tribological and corrosion component in biological environments are not well understood. Moreover, the wide range of variables involved in the tribo-corrosion process, and the variety of materials used in such conditions, means that there are few systematic studies where materials and operating conditions are optimized. In the total replacement of hip joints, the Co-Cr/UHMWPE couple has been used widely. However, the application of any replacement joint for biological conditions will depend on many factors including the activity of the patient and the overall load imposed on the artificial joint. This means evaluation of the tribo-corrosion behaviour over a multi parameter space is important in order to assess the degradation possible for many patient/activity and body mass categories.In this work, the performance of a Co-Cr/UHMWPE couple was evaluated in Ringer's solution in a tribological situation where micron size particles particles were entrained in the contact - micro-abrasion-corrosion. The effects of applied load and potential were investigated in the study. Micro-abrasion-corrosion maps were constructed for the material indicating the mechanism of degradation, the extent of wastage and of synergy/antagonism involved in the tribo-corrosion interaction
Monopole clusters, Z(2) vortices and confinement in SU(2)
We extend our previous study of magnetic monopole currents in the maximally
Abelian gauge [hep-lat/9712003] to larger lattices at small lattice spacings
(20^4 at beta = 2.5 and 32^4 at beta = 2.5115). We confirm that at these weak
couplings there continues to be one monopole cluster that is very much longer
than the rest and that the string tension, K, is entirely due to it. The
remaining clusters are compact objects whose population as a function of radius
follows a power law that deviates from the scale invariant form, but much too
weakly to suggest a link with the analytically calculable size distribution of
small instantons. We also search for traces of Z(2) vortices in the Abelian
projected fields; either as closed loops of `magnetic' flux or through
appropriate correlations amongst the monopoles. We find, by direct calculation,
that there is no confining condensate of such flux loops. We also find, through
the calculation of doubly charged Wilson loops within the monopole fields, that
there is no suppression of the q=2 effective string tension out to at distances
of at least r ~ 1.6/sqrt{K}, suggesting that if there are any vortices they are
not encoded in the monopole fields.Comment: 26 pages of LaTeX and PostScript figure
The Coulomb law in the pure gauge U(1) theory on a lattice
We study the heavy charge potential in the Coulomb phase of pure gauge
compact U(1) theory on the lattice. We calculate the static potential
from Wilson loops on a lattice and compare
with the predictions of lattice perturbation theory. We investigate finite size
effects and, in particular, the importance of non-Coulomb contributions to the
potential. We also comment on the existence of a maximal coupling in the
Coulomb phase of pure gauge U(1) theory.Comment: 14 pages. LaTeX file and 3 postscript figure
Abelian Monopoles in SU(2) Lattice Gauge Theory as Physical Objects
By numerical calculations we show that the abelian monopole currents are
locally correlated with the density of SU(2) lattice action. The correlations
are larger by the order of magnitude in the maximal abelian projection than in
the projections which correspond to the diagonalization of Polyakov line and to
the diagonalization of the plaquette. These facts show that (at least) in the
maximal abelian projection the monopoles are the physical objects, they carry
the SU(2) action. The larger value of \beta, the larger the relative action
carried by monopole. Calculations on the asymmetric lattice show that this
correlation exists also in the deconfinement phase of gluodynamics.Comment: 6 pages, RevTeX, 3 figures, uses epsf.sty; to be published in
Phys.Rev.Lett., replaced to match version accepted for publicatio
Dynamics of Monopoles and Flux Tubes in Two-Flavor Dynamical QCD
We investigate the confining properties of the QCD vacuum with
flavors of dynamical quarks, and compare the results with the properties of the
quenched theory. We use non-perturbatively improved Wilson
fermions to keep cut-off effects small. We focus on color magnetic monopoles.
Among the quantities we study are the monopole density and the monopole
screening length, the static potential and the profile of the color electric
flux tube. We furthermore derive the low-energy effective monopole action.
Marked differences between the quenched and dynamical vacuum are found.Comment: 34 pages, 28 figures, Late
Dual Superconductor Scenario of Confinement: A Systematic Study of Gribov Copy Effects
We perform a study of the effects from maximal abelian gauge Gribov copies in
the context of the dual superconductor scenario of confinement, on the basis of
a novel approach for estimation of systematic uncertainties from incomplete
gauge fixing. We present numerical results, in SU(2) lattice gauge theory,
using the overrelaxed simulated annealing gauge fixing algorithm. We find
abelian and non-abelian string tensions to differ significantly, their ratio
being 0.92(4) at BETA = 2.5115. An approximate factorization of the abelian
potential into monopole and photon contributions has been confirmed, the former
giving rise to the abelian string tension.Comment: 35 pages uucompressed LaTeX with 10 encapsuled postscript figure
Vortex critical behavior at the de-confinement phase transition
The de-confinement phase transition in SU(2) Yang-Mills theory is revisited
in the vortex picture. Defining the world sheets of the confining vortices by
maximal center projection, the percolation properties of the vortex lines in
the hypercube consisting of the time axis and two spatial axis are studied.
Using the percolation cumulant, the temperature for the percolation transition
is seen to be in good agreement with the critical temperature of the thermal
transition. The finite size scaling function for the cumulant is obtained. The
critical index of the finite size scaling function is consistent with the index
of the 3D Ising model.Comment: 4 pages, 4 PS figures, using revtex4, paragraph and refs added, typo
correcte
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