261,582 research outputs found

### Chromoelectric Knot in QCD

We argue that the Skyrme theory describes the chromomagnetic (not
chromoelectric) dynamics of QCD. This shows that the Skyrme theory could more
properly be interpreted as an effective theory which is dual to QCD, rather
than an effective theory of QCD itself. This leads us to predict the existence
of a new type of topological knot, a twisted chromoelectric flux ring, in QCD
which is dual to the chromomagnetic Faddeev-Niemi knot in Skyrme theory. We
estimate the mass and the decay width of the lightest chromoelectric knot to be
around $50 GeV$ and $117 MeV$.Comment: 4 page

### Knot Topology of QCD Vacuum

We show that one can express the knot equation of Skyrme theory completely in
terms of the vacuum potential of SU(2) QCD, in such a way that the equation is
viewed as a generalized Lorentz gauge condition which selects one vacuum for
each class of topologically equivalent vacua. From this we show that there are
three ways to describe the QCD vacuum (and thus the knot), by a non-linear
sigma field, a complex vector field, or by an Abelian gauge potential. This
tells that the QCD vacuum can be classified by an Abelian gauge potential with
an Abelian Chern-Simon index.Comment: 4 page

### Non-locality of Hydrodynamic and Magnetohydrodynamic Turbulence

We compare non-locality of interactions between different scales in
hydrodynamic (HD) turbulence and magnetohydrodynamic (MHD) turbulence in a
strongly magnetized medium. We use 3-dimensional incompressible direct
numerical simulations to evaluate non-locality of interactions. Our results
show that non-locality in MHD turbulence is much more pronounced than that in
HD turbulence. Roughly speaking, non-local interactions count for more than
10\% of total interactions in our MHD simulation on a grid of $512^3$ points.
However, there is no evidence that non-local interactions are important in our
HD simulation with the same numerical resolution. We briefly discuss how
non-locality affects energy spectrum.Comment: 6 pages, 5 figure

### Faddeev-Niemi Conjecture and Effective Action of QCD

We calculate a one loop effective action of SU(2) QCD in the presence of the
monopole background, and find a possible connection between the resulting QCD
effective action and a generalized Skyrme-Faddeev action of the non-linear
sigma model. The result is obtained using the gauge-independent decomposotion
of the gauge potential into the topological degrees which describes the
non-Abelian monopoles and the local dynamical degrees of the potential, and
integrating out all the dynamical degrees of QCD.Comment: 6 page

### Interpreting Power Anisotropy Measurements in Plasma Turbulence

A relationship is derived between power anisotropy and wavevector anisotropy
in turbulent fluctuations. This can be used to interpret plasma turbulence
measurements, for example in the solar wind. If fluctuations are anisotropic in
shape then the ion gyroscale break point in spectra in the directions parallel
and perpendicular to the magnetic field would not occur at the same frequency,
and similarly for the electron gyroscale break point. This is an important
consideration when interpreting solar wind observations in terms of anisotropic
turbulence theories. Model magnetic field power spectra are presented assuming
a cascade of critically balanced Alfven waves in the inertial range and kinetic
Alfven waves in the dissipation range. The variation of power anisotropy with
scale is compared to existing solar wind measurements and the similarities and
differences are discussed.Comment: 5 pages, 3 figures, published versio

### Stable Monopole-Antimonopole String Background in SU(2) QCD

Motivated by the instability of the Savvidy-Nielsen-Olesen vacuum we make a
systematic search for a stable magnetic background in pure SU(2) QCD. It is
shown that a pair of axially symmetric monopole and antimonopole strings is
stable, provided that the distance between the two strings is less than a
critical value. The existence of a stable monopole-antimonopole string
background strongly supports that a magnetic condensation of
monopole-antimonopole pairs can generate a dynamical symmetry breaking, and
thus the magnetic confinement of color in QCD.Comment: 7 page

### The Price of an Electroweak Monopole

In a recent paper, Cho, Kim and Yoon (CKY) have proposed a version of the
SU(2) $\times$ U(1) Standard Model with finite-energy monopole and dyon
solutions. The CKY model postulates that the effective U(1) gauge coupling $\to
\infty$ very rapidly as the Englert-Brout-Higgs vacuum expectation value $\to
0$, but in a way that is incompatible with LHC measurements of the Higgs boson
$H \to \gamma \gamma$ decay rate. We construct generalizations of the CKY model
that are compatible with the $H \to \gamma \gamma$ constraint, and calculate
the corresponding values of the monopole and dyon masses. We find that the
monopole mass could be $< 5.5$ TeV, so that it could be pair-produced at the
LHC and accessible to the MoEDAL experiment.Comment: 15 pages; Two clarifying footnotes (3 and 4) added. No effect on
conclusion

### Abelian Decomposition of Sp(2N) Yang-Mills Theory

In the previous paper, we generalized the method of Abelian decomposition to
the case of SO(N) Yang-Mills theory. This method that was proposed by Faddeev
and Niemi introduces a set of variables for describing the infrared limit of a
Yang-Mills theory. Here, we extend the decomposition method further to the
general case of four-dimensional Sp(2N) Yang-Mills theory. We find that the
Sp(2N) connection decomposes according to irreducible representations of SO(N).Comment: latex, 8 page

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