170 research outputs found
Confining string and its widening in HP1 embedding approach
Structure of confining string in terms of the topological charge density and
the action density is studied in SU(2) Yang-Mills theory on the lattice using
HP1 sigma-model embedding approach. We find that the confining flux tube
noticeably suppresses both the topological charge and the action densities.
Beyond the string formation length the string cross section in terms of these
quantities is well described by a Gaussian profile. In both cases the squared
string width is found to be a logarithmic function of the string length
confirming the Luscher widening of the chromoelectric string. Characteristic
string scales in terms of the topological and action densities are estimated as
well.Comment: 13 pages, 20 figures, RevTeX 4.0; replaced to match published versio
Topological Content of the Electroweak Sphaleron on the Lattice
3D electroweak sphalerons on the lattice are used as test configurations for
definitions of various topological defects. In the maximally Abelian gauge they
are shown to contain a symmetric array of Abelian monopoles and anti-monopoles
connected by two kinds of Abelian vortex strings. Gauge-invariant lattice
definitions of the Nambu monopole and the Z-vortex string are formulated which
correspond to Abelian projection from the unitary gauge. The sphalerons contain
in their core just one (non-Abelian) Nambu monopole-anti-monopole pair
(connected by a Z-string) in an unstable saddle point bound state. This
provides an example for the monopole-pair unbinding mechanism expected to work
at the electroweak phase transition. The definitions of defects developed here
will be used in future studies of topological aspects of this transition.Comment: 13 pages, LaTeX, 9 figures, uses epsf.sty; The sign in eq.(13) is
corrected; to appear in Phys.Lett.
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