Gauge invariance of the dual Meissner effect in QCD

TL;DR

This paper demonstrates the gauge-invariant dual Meissner effect in lattice SU(2) QCD through numerical simulations, defining gauge-invariant quantities and confirming the dual London equation in the long-range regime.

Contribution

It introduces a gauge-invariant framework for observing the dual Meissner effect in lattice QCD using novel Abelian-like field strength and monopole definitions.

Findings

Gauge-invariant monopole-like quantities are defined and observed.

The squeezing of the electric field is caused by gauge-invariant monopoles.

An equation similar to the dual London equation is approximately confirmed.

Abstract

The dual Meissner effect is described and numerically observed in a gauge-invariant way in lattice Monte-Carlo simulations of pure SU(2) QCD. A gauge-invariant Abelian-like field strength is defined in terms of a unit-vector in color space which is constructed by a non-Abelian field strength itself. A gauge-invariant monopole-like quantity is defined by a violation of the Bianchi identity with respect to the Abelian-like field strength. The squeezing of the non-Abelian electric field $\sqrt{\sum_a(E^a_i)^2}$ between a pair of static quark and anti-quark occurs due to the solenoidal current coming from the gauge-invariant monopole-like quantity. An equation similar to the dual London equation is confirmed approximately in the long-range region.