4,106 research outputs found
't Hooft tensor for generic gauge group
We study monopoles in gauge theories with generic gauge group. Magnetic
charges are in one-to-one correspondence with the second homotopy classes at
spatial infinity (), which are therefore identified by the 't Hooft
tensor. We determine the 't Hooft tensor in the general case. These issues are
relevant to the understanding of Color Confinement.Comment: 5 pages. Contribution to the Conference QCD08, Montpellier 7-12 July
2008 To appear in the proceeding
Magnetic charge superselection in the deconfined phase of Yang-Mills theory
The vacuum expectation value of an operator carrying magnetic charge is
studied numerically for temperatures above the deconfinement temperature in
SU(2) and SU(3) gauge theory. By analyzing its finite size behaviour, this is
found to be exactly zero in the thermodynamical limit for any T > T_c whenever
the magnetic charge of the operator is different from zero. These results show
that magnetic charge is superselected in the hot phase of quenched QCD.Comment: 4 pages, 6 figures, revtex
Vortices versus monopoles in color confinement
We construct the creation operator of a vortex for SU(2) pure gauge theory
using the methods developed for monopoles. We interpret its vacuum expectation
value as a disorder parameter for the deconfinement phase transition and find
that it behaves in the vacuum in a similar way to monopoles. Results are
extrapolated to the thermodynamical limit using finite-size scaling.Comment: Talk presented at Lattice2000 (Topology and Vacuum), 4 page
Monopoles, vortices and confinement in SU(3) gauge theory
We compute, in SU(3) pure gauge theory, the vacuum expectation value (vev) of
the operator which creates a vortex wrapping the lattice through periodic
boundary conditions (dual Polyakov line). The technique used is the same
already tested in the SU(2) case. The dual Polyakov line proves to be a good
disorder parameter for confinement, and has a similar behaviour to the monopole
condensate. The new features which characterise the construction of the
disorder operator in SU(3) are emphasised.Comment: 8 pages, 4 eps figures, typed with elsart.cl
Dual Superconductivity and Chiral Symmetry in Full QCD
A disorder parameter detecting dual superconductivity of the vacuum is
measured across the chiral phase transition in full QCD with two flavours of
dynamical staggered fermions. The observed behaviour is similar to the quenched
case.Comment: Lattice2001(confinement) proceedings, 3 pages, 2 eps figure
Dual superconductivity and vacuum properties in Yang--Mills theories
We address, within the dual superconductivity model for color confinement,
the question whether the Yang-Mills vacuum behaves as a superconductor of type
I or type II. In order to do that we compare, for the theory with gauge group
SU(2), the determination of the field penetration depth with that of
the superconductor correlation length . The latter is obtained by
measuring the temporal correlator of a disorder parameter developed by the Pisa
group to detect dual superconductivity. The comparison places the vacuum close
to the border between type I and type II and marginally on the type II side. We
also check our results against the study of directly measurable effects such as
the interaction between two parallel flux tubes, obtaining consistent
indications for a weak repulsive behaviour. Future strategies to improve our
investigation are discussed.Comment: 23 pages, 15 figures. Simulations on finer lattices and with
different monopole charges added. Final version to be published in Nuclear
Physics
Deconfining transition in two-flavor QCD
The order and the nature of the finite-temperature phase transition of QCD
with two flavors of dynamical quarks is investigated. An analysis of the
critical exponent of the specific heat is performed through finite-size and
finite-mass scaling of various susceptibilities. Dual superconductivity of QCD
vacuum is investigated using a disorder parameter, namely the v.e.v. of a
monopole creation operator. Hybrid R simulations were run at lattice spatial
sizes of , , and and temporal size , with
quark masses in the range .Comment: Lattice2003(topology), 3 page
Monopole condensation in the ground state of gauge theories: a disorder parameter
We construct a disorder parameter for dual superconductivity of the ground
state of gauge theory.Comment: 3 pages, contribution to the Lattice '94 conference, shell archive
containing uuencoded LATEX file + 2 figure
Colour confinement and dual superconductivity of the vacuum - I
We study dual superconductivity of the ground state of SU(2) gauge theory, in
connection with confinement. We do that measuring on the lattice a disorder
parameter describing condensation of monopoles. Confinement appears as a
transition to dual superconductor, independent of the abelian projection
defining monopoles. Some speculations are made on the existence of a more
appropriate disorder parameter. A similar study for SU(3) is presented in a
companion paper.Comment: Some typos corrected, acknowledgements added; to appear on Phys. Rev.
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