Impact of Dynamical Fermions on QCD Centre Vortices

Abstract

The origin of quark confinement from the theory of Quantum Chromodynamics (QCD) is a subject of great interest. The centre vortex model has been proposed as a possible explanation for this property, with remarkable success having been demonstrated over the past 40 years. In this work, we push this model in two new directions. The first is an exploration of the geometric structure of centre vortices as they appear in lattice simulations. This allows for a detailed examination of the correlation between centre vortices and topological charge, as well as an exploration of vortex branching and percolation in QCD. The second direction explored is the transition from pure-gauge theory to full QCD, where gluons transition to dynamical quark-antiquark pairs. The effect of the introduction of dynamical quarks is explored in the context of the static quark potential, gluon propagator and Euclidean correlator. These calculations reveal the remarkable impact of dynamical fermions on the structure of centre vortices, and for the first time finds quantitative agreement between the vortex-only and original gauge fields. These results reveal the important connection between dynamical fermions and centre vortices, further reinforcing the crucial role centre vortices play in generating confinement in QCD.