39,963 research outputs found
Stability of the Magnetic Monopole Condensate in three- and four-colour QCD
It is argued that the ground state of three- and four-colour QCD contains a
monopole condensate, necessary for the dual Meissner effect to be the mechanism
of confinement, and support its stability on the grounds that it gives the
off-diagonal gluons an effective mass sufficient to remove the unstable ground
state mode.Comment: jhep.cls, typos corrected, references added, some content delete
QCD effective action with a most general homogeneous field background
We consider one-loop effective action of SU(3) QCD with a most general
constant chromomagnetic (chromoelectric) background which has two independent
Abelian field components. The effective potential with a pure magnetic
background has a local minimum only when two Abelian components H_{\mu\nu}^3
and H_{\mu\nu}^8 of color magnetic field are orthogonal to each other. The
non-trivial structure of the effective action has important implication in
estimating quark-gluon production rate and p_T-distribution in quark-gluon
plasma. In general the production rate depends on three independent Casimir
invariants, in particular, it depends on the relative orientation between
chromoelectric fields.Comment: 6 pages, 3 figures (9 pages in published version
Abelian Dominance in Wilson Loops
It has been conjectured that the Abelian projection of QCD is responsible for
the confinement of color. Using a gauge independent definition of the Abelian
projection which does {\it not} employ any gauge fixing, we provide a strong
evidence for the Abelian dominance in Wilson loop integral. In specific we
prove that the gauge potential which contributes to the Wilson loop integral is
precisely the one restricted by the Abelian projection.Comment: 4 pages, no figure, revtex. Phys. Rev. D in pres
Varying c cosmology and Planck value constraints
It has been suggested that by increasing the speed of light during the early
universe various cosmological problems of standard big bang cosmology can be
overcome, without requiring an inflationary phase. However, we find that as the
Planck length and Planck time are then made correspondingly smaller, and
together with the need that the universe should not re-enter a Planck epoch,
the higher models have very limited ability to resolve such problems. For a
constantly decreasing the universe will quickly becomes quantum
gravitationally dominated as time increases: the opposite to standard cosmology
where quantum behaviour is only ascribed to early times.Comment: extended versio
Partially Dual variables in SU(2) Yang-Mills Theory
We propose a reformulation of SU(2) Yang-Mills theory in terms of new
variables. These variables are appropriate for describing the theory in its
infrared limit, and indicate that it admits knotlike configurations as stable
solitons. As a consequence we arrive at a dual picture of the Yang-Mills theory
where the short distance limit describes asymptotically free, massless point
gluons and the large distance limit describes extended, massive knotlike
solitons.Comment: 4 pages, revtex twocolum
Influence Of Geometric Factors Of The Substrate On Hydrophilic Surface Modification Of Polyurethane Sponges By Plasma Treatment
The surface modification by plasma treatment occurs by consecutive processes of excitation of gas(es) and deexcitation of excited species. The deexcitation occurs primarily at the surface yielding chemical modification of the surface (nonpolymer-forming plasmas) or deposition of material (polymer-forming plasma) on the substrate surface. Because of this sequence, geometric factors of the substrate in relation to the surrounding plasma phase have crucial influence on the effectiveness of plasma treatments. Simple mathematical models were developed to illustrate the effect of geometric factors involved in plasma treatments, and experimental results obtained with porous polyurethane sponges in various sizes were examined by the mathematical models for both plasma treatments by 0, H O, and NH and plasma polymerization of acrylic acid.© 1986 American Vacuum Societ
Frozen light in photonic crystals with degenerate band edge
Consider a plane monochromatic wave incident on a semi-infinite periodic
structure. What happens if the normal component of the transmitted wave group
velocity vanishes? At first sight, zero normal component of the transmitted
wave group velocity simply implies total reflection of the incident wave. But
we demonstrate that total reflection is not the only possible outcome. Instead,
the transmitted wave can appear in the form of a frozen mode with very large
diverging amplitude and either zero, or purely tangential energy flux. The
field amplitude in the transmitted wave can exceed that of the incident wave by
several orders of magnitude. There are two qualitatively different kinds of
frozen mode regime. The first one is associated with a stationary inflection
point of electromagnetic dispersion relation. This phenomenon has been analyzed
in our previous publications. Now, our focus is on the frozen mode regime
related to a degenerate photonic band edge. An advantage of this new phenomenon
is that it can occur in much simpler periodic structures. This spectacular
effect is extremely sensitive to the frequency and direction of propagation of
the incident plane wave. These features can be very attractive in a variety
practical applications, such as higher harmonic generation and wave mixing,
light amplification and lasing, highly efficient superprizms, etc
Radiative Transitions in Heavy Mesons in a Relativistic Quark Model
The radiative decays of , , and other excited heavy mesons are
analyzed in a relativistic quark model for the light degrees of freedom and in
the limit of heavy quark spin-flavor symmetry. The analysis of strong decays
carried out in the corresponding chiral quark model is used to calculate the
strong decays and determine the branching ratios of the radiative decays.
Consistency with the observed branching ratios requires the inclusion of the
heavy quark component of the electromagnetic current and the introduction of an
anomalous magnetic moment for the light quark. It is observed that not only
, but also meson transitions within a heavy quark spin multiplet are
affected by the presence of the heavy quark current.Comment: 9 pages, RevTeX. Submitted to Physical Review
Near-Perfect Correlation of the Resistance Components of Mesoscopic Samples at the Quantum Hall Regime
We study the four-terminal resistance fluctuations of mesoscopic samples near
the transition between the and the quantum Hall states. We
observe near-perfect correlations between the fluctuations of the longitudinal
and Hall components of the resistance. These correlated fluctuations appear in
a magnetic-field range for which the two-terminal resistance of the samples is
quantized. We discuss these findings in light of edge-state transport models of
the quantum Hall effect. We also show that our results lead to an ambiguity in
the determination of the width of quantum Hall transitions.Comment: As publishe
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