arXiv subjects
Publications and source records attributed to V. G. Bornyakov.
We present results of measurements of various geometrical characteristics of the monopole clusters in the maximally Abelian projection of SU(2) lattice gauge theory. We observe scaling for the observables tested. Short clusters correspond to random walks at small scale but have long-range correlations at the hadronic scale. On the other hand, the percolating cluster at the hadronic scale does not correspond to a random walk.
Propagators of diagonal and off-diagonal gluons are studied numerically in the Maximally Abelian gauge of the SU(2) lattice gauge theory. We have found the strong enhancement of the diagonal gluon in the infrared region. The enhancement factor is about 50 at the smallest available momentum, 325 MeV. We discuss also various analytical fits to the propagators.
We present measurements of various geometrical characteristics of monopole clusters in SU(2) lattice gauge theory. The maximal Abelian projection is employed and both infinite, or percolating cluster and finite clusters are considered. In particular, we observe scaling for average length of segments of the percolating cluster between self-crossings, correlators of vacuum monopole currents, angular correlation between links along trajectories. Short clusters are random walks and their spectrum in length corresponds to free particles. At the hadronic scale, on the other hand, the monopole trajectories are no longer random walks. Moreover, we argue that the data on the density of finite clusters suggest that there are long-range correlations between finite clusters which can be understood as association of the clusters with two-dimensional surfaces, whose area scales.
We perform the careful study of the Gribov copies problem in SU(2) lattice gauge theory for maximal direct and maximal indirect center projections. We find that this problem is much more severe than it was thought before. The projected string tension is not in agreement with the physical string tension. We also show that the particle--like objects, nexuses, might be important for the confinement dynamics.
We study propagators of diagonal and off-diagonal gluons in the momentum space in maximal abelian gauge of SU(2) lattice gauge theory. Remaining U(1) degrees of freedom are fixed using Landau gauge. We find substantial difference between the propagator of the diagonal and the off-diagonal gluon in the infrared region. The propagator of the off-diagonal gluon is suppressed in comparison with that of the diagonal gluon at small momenta. In the ultraviolet region both propagators behave as in nonabelian Landau gauge.
We study the distribution of P-vortices near the confining string in the indirect Z(2) projection of SU(2) lattice gauge theory. It occurs that the density of vortices is constant at large distances and strongly suppressed near the line connecting the test quark-antiquark pair. This means that the condensate of P-vortices is broken inside the confining string. We also find that the width of the P-vortex density distribution is proportional to the logarithm of the distance between the quark and antiquark.
We study the Abelian and non-Abelian action densitynear the monopole in the maximal Abelian gauge of SU(2) lattice gauge theory. We find that the non-Abelian action density near the monopoles belonging to the percolating cluster decreases when we approach the monopole center. Our estimate of the monopole radius is R_mon ~ 0.04 fm.
We present results of the careful study of the Gribov copies problem in SU(2) lattice gauge theory for the direct maximal center projection widely used in confinement studies. Applying simulated annealing algorithm we demonstrate that this problem is more severe than it was thought before. The projected (gauge noninvariant) string tension is not in the agreement with the physical string tension. We do not find any indications that P-vortices reproduce the full SU(2) string tension neither in the infinite volume limit nor in the continuum limit.
We perform the careful study of the gauge copies problem for the direct center projection in SU(2) lattice gauge theory. Our results indicate that this gauge is not appropriate for the investigation of the center vortices. We also show that the point-like objects, nexuses, are important for the confinement dynamics.
Photon correlators in $~U(1)~$ pure gauge theory for different lattice actions are considered under the Lorentz gauge condition. They are shown to depend strongly on the gauge fixing ambiguity and on the corresponding existence of Dirac sheets. For the Coulomb phase a gauge fixing algorithm is proposed which avoids Dirac sheets and allows to find the global extremum of the non-local gauge condition. Sorry, figures are not included and can be sent by ordinary mail.
We study properties of the compact $~4D~$ $U(1)$ lattice gauge theory with monopoles {\it removed}. Employing Monte Carlo simulations we calculate correlators of scalar, vector and tensor operators at zero and nonzero momenta $~\vec{p}~$. We confirm that the theory without monopoles has no phase transition, at least, in the interval $~0 < β\leq 2~$. There the photon becomes massless and fits the lattice free field theory dispersion relation very well. The energies of the $~0^{++}~$, $~1^{+-}~$ and $~2^{++}~$ states show a rather weak dependence on the coupling in the interval of $~β~$ investigated, and their ratios are practically constant. We show also a further modification of the theory suppressing the negative plaquettes to improve drastically the overlap with the lowest states (at least, for $~J=1$).