Monopoles of the Dirac type and color confinement in QCD -- First results of SU(3) numerical simulations without gauge fixing

TL;DR

This paper demonstrates that Abelian monopoles of the Dirac type in SU(3) QCD are responsible for color confinement, showing perfect Abelian dominance and the dual Meissner effect through numerical lattice simulations without gauge fixing.

Contribution

It provides the first numerical evidence of Abelian monopole dominance and the dual Meissner effect in SU(3) QCD without gauge fixing, supporting the Abelian dual superconductor model of confinement.

Findings

Perfect Abelian dominance reproduces string tension.

Abelian electric fields are squeezed by monopole currents.

Vacuum behaves as a weak type I dual superconductor.

Abstract

If non-Abelian gauge fields in $SU(3)$ QCD have a line-singularity leading to non-commutativity with respect to successive partial-derivative operations, the non-Abelian Bianchi identity is violated. The violation as an operator is shown to be equivalent to violation of Abelian-like Bianchi identities. Then there appear eight Abelian-like conserved magnetic monopole currents of the Dirac type in $SU(3)$ QCD. Exact Abelian (but kinematical) symmetries appear in non-Abelian $SU(3)$ QCD. Here we try to show the Abelian dual Meissner effect due to the above Abelian-like monopoles are responsible for color confinement in $SU(3)$ QCD. If this picture is correct, the string tension of non-Abelian Wilson loops is reproduced fully by that of the Abelian Wilson loops. This is called as perfect Abelian dominance. In this report, the perfect Abelian dominance is shown to exist with the help of the multilevel method but without introducing additional smoothing techniques like partial gauge fixings, although lattice sizes studied are not large enough to study the infinite volume limit. Perfect monopole dominance is also shown without any additional gauge fixing. Abelian electric fields are squeezed due to solenoidal monopole currents and the penetration length for an Abelian electric field of a single color is the same as that of non-Abelian electric field. The coherence length is also measured directly through the correlation of the monopole density and the Polyakov loop pair. The Ginzburg-Landau parameter indicates that the vacuum type is the weak type I (dual) superconductor. The results obtained above without any additional assumptions as well as more clear previous $SU(2)$ results seem to suggest strongly the above Abelian dual Meissner picture of color confinement mechanism.