470 research outputs found
Dual Superconductor Mechanism of Confinement on the Lattice
We investigate the dual superconductor mechanism of confinement for pure
SU(2) lattice gauge theory in the maximally abelian gauge. We focus on the the
dual Meissner effect. We find that the transverse distribution of the
longitudinal chromoelectric field due to a static quark-antiquark pair
satisfies the dual London equation. Moreover we show that the size of the flux
tube scales according to asymptotic freedom.Comment: LaTeX, 9 pages, 6 figures available as a PostScript file from L.
Cosmai, BARI - TH 110/9
Creutz Ratios From Color-Truncated Lattice Configurations
We investigate whether information about Creutz ratios is encoded,
separately, in each gluon color component of numerically generated lattice
configurations. Working in SU(2) lattice gauge theory in Landau gauge, we set
two of the three gluon color components to zero, and compensate for the loss of
two-thirds of the fluctuation by simply rescaling the remaining component by a
factor of . Creutz ratios are then computed with this "abelianized"
configuration. We find that the Creutz ratios of loops constructed from
abelianized links converge to the usual Creutz ratios in the scaling regime.Comment: 5 pages, plain LaTeX, one figur
String tension and monopoles in SU(2) QCD
Monopole and photon contributions to abelian Wilson loops are calculated
using Monte-Carlo simulations of finite-temperature QCD in the
maximally abelian gauge. Long monopole loops alone are responsible for the
behavior of the string tension in the confinement phase up to the critical
. Short monopole loops and photons do not contribute to the string
tension. The abelian and the monopole spacial string tensions (both of which
agree with the normal ones for ) show a scaling
behavior in the deconfinement phase. The abelian spacial string tension is in
agreement with the full one even in the deconfinement phase.Comment: 10 Pages + 1 table + 8 figures, KANAZAWA 94-1
Recent Results on the Abelian Projection of Lattice Gluodynamics
The abelian projection of lattice gluodynamics is reviewed. The main topics
are: abelian and monopole dominance, monopole condensate as the disorder
parameter, effective abelian Lagrangian, monopoles in the instanton field,
Aharonov -- Bohm effect on the lattice.Comment: 7 pages, LaTeX, 7 PS figures, Talk presented at LATTICE9
On the perfect lattice actions of abelian-projected SU(2) QCD
We study the perfect lattice actions of abelian-projected SU(2) gluodynamics.
Using the BKT and duality transformations on the lattice, an effective string
model is derived from the direction-dependent quadratic monopole action,
obtained numerically from SU(2) gluodynamics in maximally abelian gauge. The
string tension and the restoration of continuum rotational invariance are
investigated using strong coupling expansion of lattice string model
analytically. We also found that the block spin transformation can be performed
analytically for the quadratic monopole action.Comment: 3 pages, Latex, 1 figures; talk presented at LATTICE9
Various representations of infrared effective lattice QCD
We study various representations of the infrared effective theory of SU(2)
gluodynamics starting from the monopole action derived recently.
We determine the coupling constants in the abelian-Higgs model directly from
lattice QCD and evaluate the type of the QCD vacuum. The string action is
derived using the BKT transformation on the lattice. At the classical level
this action reproduces the physical string tension with a good accuracy.Comment: 3 pages, LaTeX, 2 figures; talk presented at LATTICE9
Evidence of Strong Correlation between Instanton and QCD-monopole on SU(2) Lattice
The correlation between instantons and QCD-monopoles is studied both in the
lattice gauge theory and in the continuum theory. An analytical study in the
Polyakov-like gauge, where is diagonalized, shows that the
QCD-monopole trajectory penetrates the center of each instanton, and becomes
complicated in the multi-instanton system. Using the SU(2) lattice with ,
the instanton number is measured in the singular (monopole-dominating) and
regular (photon-dominating) parts, respectively. The monopole dominance for the
topological charge is found both in the maximally abelian gauge and in the
Polyakov gauge.Comment: 4 pages, Latex, 3 figures. Talk presented by H. Suganuma at
International Symposium on 'Lattice Field Theory', July 11 - 15, 1995,
Melbourne, Australi
Room temperature and low-field resonant enhancement of spin Seebeck effect in partially compensated magnets
Resonant enhancement of spin Seebeck effect (SSE) due to phonons was recently
discovered in Y3Fe5O12 (YIG). This effect is explained by hybridization between
the magnon and phonon dispersions. However, this effect was observed at low
temperatures and high magnetic fields, limiting the scope for applications.
Here we report observation of phonon-resonant enhancement of SSE at room
temperature and low magnetic field. We observed in Lu2BiFe4GaO12 and
enhancement 700 % greater than that in a YIG film and at very low magnetic
fields around 10-1 T, almost one order of magnitude lower than that of YIG. The
result can be explained by the change in the magnon dispersion induced by
magnetic compensation due to the presence of non-magnetic ion substitutions.
Our study provides a way to tune the magnon response in a crystal by chemical
doping with potential applications for spintronic devices.Comment: 17 pages, 4 figure
- …