Lattice instanton action from 3D SU(2) Georgi-Glashow model

3D Georgi-Glashow model is studied on the lattice in the London limit in an infrared but an intermediate region before the screening appears. Abelian and instanton dominances are observed after abelian projections in a unitary gauge and roughly in the maximally abelian gauge. Using an inverse Monte-Carlo method, we determine an effective instanton action in both gauges. When we restrict ourselves to some regions of parameters $\beta$ and $\kappa$, we obtain an almost perfect instanton action, performing a block-spin transformation on the dual lattice. It takes a form of a Coulomb gas and reproduces fairly well the string tension obtained analytically by Polyakov. The almost perfect actions in both gauges look the same in the infrared region, which suggests gauge independence.Comment: 26 pages, 16 figure

Monopoles of the Dirac type and color confinement in QCD -- Study of the continuum limit

Non-Abelian gauge fields having a line-singularity of the Dirac type lead us to violation of the non-Abelian Bianchi identity. The violation as an operator is equivalent to violation of Abelian-like Bianchi identities corresponding to eight Abelian-like conserved magnetic monopole currents of the Dirac type in $SU(3)$ QCD. It is very interesting to study if these new Abelian-like monopoles are responsible for color confinement in the continuum $SU(3)$ QCD, since any reliable candidate of color magnetic monopoles is not known yet. If these new Abelian-like monopoles exist in the continuum limit, the Abelian dual Meissner effect occurs, so that the linear part of the static potential between a quark-antiquark pair is reproduced fully by those of Abelian and monopole static potentials. These phenomena are called here as perfect Abelian and monopole dominances. It is shown that the perfect Abelian dominance is reproduced fairly well, whereas the perfect monopole dominance seems to be realized for large $\beta$ when use is made of the smooth lattice configurations in the maximally Abelian (MA) gauge. Making use of a block spin transformation with respect to monopoles, the scaling behaviors of the monopole density and the effective monopole action are studied. Both monopole density and the effective monopole action which are usually a two-point function of $\beta$ and the number of times $n$ of the block spin transformation are a function of $b=na(\beta)$ alone for $n=1,2,3,4,6,8,12$. If the scaling behavior is seen for up to larger $n$, it shows the existence of the continuum limit, since $a(\beta)\to 0$ when $n\to\infty$ for fixed $b=na(\beta)$. Along with the previous results without any gauge fixing, these new results obtained in MA gauge suggest that the new Abelian-like monopoles play the role of color confinement in $SU(3)$ QCD.Comment: 10 pages, 10 figures, to appear in Phys.Rev.D. arXiv admin note: text overlap with arXiv:2207.0443

Entropy of spatial monopole currents in pure SU(2) QCD at finite temperature

We study properties of space-like monopole trajectories in the Maximal Abelian gauge of quenched SU(2) QCD at the finite temperature. We concentrate on infrared monopole clusters which are responsible for the confinement properties of the theory. We determine numerically the effective action of the monopoles projected onto the three-dimensional time-slice. Then we derive the length distributions of the monopole loops and fix their entropy.Comment: 12 pages, 22 figures, RevTeX

Deconfinement transition and monopoles in T≠0T\neq0 SU(2)SU(2) QCD

The role of monopoles in the deconfinement transition is discussed in the framework of abelian projection in the maximally abelian gauge in $T\neq0$ $SU(2)$ QCD. Only one (or a few near $\beta_c$) long connected monopole loop exists uniformly through the whole lattice in each vacuum configuration in addition to some very short loops in the confinement phase and the long loop disappears in the deep deconfinement region. Energy-entropy balance of the long loops of maximally extended monopoles explains the existence of the deconfinement transition and reproduces roughly the value of the critical temperature.Comment: 23 pages (14 figures) ,late