Dynamical fermions, centre vortices, and emergent phenomena

TL;DR

This paper investigates how dynamical fermions influence centre vortex structures in lattice QCD and their role in confinement and chiral symmetry breaking, revealing significant modifications and insights into QCD vacuum phenomena.

Contribution

It provides a comparative analysis of centre vortex structures in pure-gauge and dynamical-fermion lattice QCD, highlighting their impact on confinement and mass generation.

Findings

Dynamical fermions significantly alter centre vortex structures.

Changes in vortex structures affect confinement measures like string tension.

Dynamical fermions influence dynamical mass generation and gluon propagator positivity.

Abstract

The non-trivial ground-state vacuum fields of QCD form the foundation of matter. Here we examine the centre vortices identified within the ground-state fields of lattice QCD. We aim to understand the manner in which dynamical fermions in the QCD vacuum alter the centre-vortex structure. Using modern visualisation techniques, the centre-vortex structure of pure-gauge and dynamical-fermion fields is quantified and compared. We then explore the impact this modified structure has on measures of confinement and dynamical mass generation. The string tension of the static quark potential, positivity-violation in the gluon propagator, and dynamical mass generation in the overlap quark propagator are of particular interest. The impact of dynamical fermions is significant and provides new insights into the role of centre vortices in underpinning both confinement and dynamical chiral symmetry breaking in QCD.