35 research outputs found
On the non-Abelian Stokes theorem in SU(2) gluodynamics
We discuss the non-Abelian Stokes theorem for SU(2) gauge fields which avoids
both additional integration variables and surface ordering. The idea is to
introduce the instant color orientation of the flux piercing the loop. The
non-Abelian Stokes theorem is also considered on the lattice and various terms
contributing to the trace of the Wilson loop are discussed.Comment: 3 pages, 2 figures, Lattice2003(topology
On Nonexistence of Magnetic Charge in Pure Yang-Mills Theories
We prove that magnetic charge does not exist as a physical observable on the
physical Hilbert space of the pure SU(2) gauge theory. The abelian magnetic
monopoles seen in lattice simulations are then interpreted as artifacts of
gauge fixing. The apparent physical scaling properties of the monopole density
in the continuum limit observed on the lattice are attributed to the correct
scaling properties of physical objects - magnetic vortices, as first argued by
Greensite et. al. We can show that a local gauge transformation of a certain
type can " create" abelian monopole-antimonopole pairs along magnetic vortices.
This gauge transformation exists in pure SU(N) gauge theory at any .Comment: Some references and comments adde
On the Emerging Phenomenology of <(A_\mu)^2>
We discuss phenomenology of the vacuum condensate in pure gauge
theories, where A_\mu is the gauge potential. Both Abelian and non-Abelian
cases are considered. In case of the compact U(1) the non-perturbative part of
the condensate is saturated by monopoles. In the non-Abelian case,
a two-component picture for the condensate is presented according to which
finite values of order \Lambda_{QCD}^2 are associated both with large and short
distances. We obtain a lower bound on the by considering its change
at the phase transition. Numerically, it produces an estimate similar to other
measurements. Possible physical manifestations of the condensate are discussed.Comment: 17 pp., Latex2e, 3 figure
Aharonov--Bohm Effect in 3D Abelian Higgs Theory
We study a field--theoretical analogue of the Aharonov--Bohm effect in the 3D
Abelian Higgs Model: the corresponding topological interaction is proportional
to the linking number of the vortex and the particle world trajectories. We
show that the Aharonov--Bohm effect gives rise to a nontrivial interaction of
tested charged particles.Comment: LaTeX, 3 pages, 1 figure, uses epsf.sty; talk presented at
LATTICE96(topology), St. Louis, US
Confinement and short distance physics
We consider non-perturbative effects at short distances in theories with
confinement. The analysis is straightforward within the Abelian models in which
the confinement arises on classical level. In all cases considered (compact
U(1) in 3D and 4D, dual Abelian Higgs model) there are non-perturbative
contributions associated with short distances which are due to topological
defects. In QCD case, both classical and quantum effects determine the role of
the topological defects and the theoretical analysis has not been completed so
far. Generically, the topological defects would result in 1/Q^2 corrections
going beyond the standard Operator Product Expansion. We review existing data
on the power corrections and find that the data favor existence of the novel
corrections, at least at the mass scale of (1-2) GeV. We indicate crucial
experiments which could further clarify the situation on the phenomenological
side.Comment: 11 pp., Latex2e, 4 figures, epsfig.sty. Accepted for publication in
Physics Letters
Self-tuning of the P-vortices
We observe that on the currently available lattices the non-Abelian action
associated with the P-vortices is ultraviolet divergent. On the other hand, the
total area of the vortices scales in physical units. Since both the ultraviolet
and infrared scales are manifested and there is no parameter to tune, the
observed phenomenon can be called self tuning.Comment: Lattice2003(topology
Embedded Topological Defects in Hot Electroweak Theory: a Lattice Study
We study the properties of Nambu monopoles and Z-vortices in the 3D lattice
SU(2) Higgs theory which represents the Standard Model at high temperature. We
show that the densities of the Nambu monopoles and the Z-vortices are O(1) in
the symmetric phase and generically small in the Higgs phase. Near to the
critical Higgs mass and in the vicinity of the phase transition the densities
are no more negligible in the broken phase. The percolation probability of the
Z-vortex lines is found as a new disorder parameter for this phase transition.
We conclude that the transition to the symmetric phase is accompanied by
Z-vortex condensation. Simulations comparing elementary and extended vortices
and monopoles at different \beta_G values, aiming to show that the density of
vortices and monopoles of fixed physical size might have a well-defined
continuum limit, gives encouraging but so far inconclusive results.Comment: 13 pages, LaTeX, 8 figures, epsf.sty needed; revision: minor changes
and reference adde
Z-Vortex Percolation in the Electroweak Crossover Region
We study the statistical properties of Z-vortices and Nambu monopoles in the
3D SU(2) Higgs model for a Higgs mass M_H \approx 100 GeV near and above the
crossover temperature, where these defects are thermally excited. Although
there is no phase transition at that strong selfcoupling, we observe that the
Z-vortices exhibit the percolation transition that has been found recently to
accompany the first order thermal transition that exists at smaller Higgs mass.
Above the crossover temperature percolating networks of Z-vortex lines are
ubiquitous, whereas vortices form a dilute gas of closed vortex loops and
(Nambu) monopolium states on the low-temperature side of the crossover. The
percolation temperature turns out to be roughly independent of the lattice
spacing. We find that the Higgs modulus is smaller (the gauge action is larger)
inside the vortices, compared to the bulk average. This correlation becomes
very strong on the low-temperature side. The percolation transition is a
prerequisite of some string mediated baryon number generation scenarios.Comment: 16 pages, LaTeX, 12 figures, epsf.sty needed; final version to appear
in Phys. Lett.
Heavy monopole potential in gluodynamics
We discuss predictions for the interaction energy of the fundamental
monopoles in gluodynamics introduced via the 't Hooft loop. At short distances,
the heavy monopole potential is calculable from first principles. At larger
distances, we apply the Abelian dominance models. We discuss the measurements
which would be crucial to distinguish between various models. Non-zero
temperatures are also considered. Our predictions are in qualitative agreement
with the existing lattice data. We discuss further measurements which would be
crucial to check the model.Comment: 3 pages, 1 figure, Lattice2001(confinement
Towards Abelian-like formulation of the dual gluodynamics
We consider gluodynamics in case when both color and magnetic charges are
present. We discuss first short distance physics, where only the fundamental
|Q|=1 monopoles introduced via the `t Hooft loop can be considered
consistently. We show that at short distances the external monopoles interact
as pure Abelian objects. This result can be reproduced by a Zwanziger-type
Lagrangian with an Abelian dual gluon. We introduce also an effective dual
gluodynamics which might be a valid approximation at distances where the
monopoles |Q|=2 can be considered as point-like as well. Assuming the monopole
condensation we arrive at a model which is reminiscent in some respect of the
Abelian Higgs model but, unlike the latter leaves space for the Casimir
scaling.Comment: 28+1 pp., Latex2e, 1 figur