Quark Propagation in the Instantons of Lattice QCD

Abstract

We quantitatively examine the extent to which instanton degress of freedom, contained within standard Monte-carlo generated gauge-field configurations, can maintain the characteristic features of the mass and renormalisation functions of the non-perturbative quark propagator. We use over-improved stout-link smearing to isolate instanton effects on the lattice. Using a variety of measures, we illustrate how gauge fields consisting almost solely of instanton-like objects are produced after only 50 sweeps of smearing. We find a full vacuum, with a packing fraction more than three times larger than phenomenological models predict. We calculate the overlap quark propagator on these smeared configurations, and find that even at high levels of smearing the majority of the characteristic features of the propagator are reproduced. We thus conclude that instantons contained within standard Monte-carlo generated gauge-field configurations are the degrees of freedom responsible for the dynamical generation of mass observed in lattice QCD.

References in corpus (4)

• Over-Improved Stout-Link Smearing
• Impact of Dynamical Fermions on QCD Vacuum Structure
• Wilson mass dependence of the overlap topological charge density
• Wave Functions of the Proton Ground State in the Presence of a Uniform Background Magnetic Field in Lattice QCD

Cited by in corpus (9)

• Connection between centre vortices and instantons through gauge-field smoothing
• Gluon Green functions free of Quantum fluctuations
• Overlap Quark Propagator in Coulomb Gauge QCD and the Interrelation of Confinement and Chiral Symmetry Breaking
• On Chiral Symmetry Breaking, Topology and Confinement
• Overlap quark propagator near the physical pion mass
• Instanton contributions to the low-lying hadron mass spectrum
• On the low-energy spectrum of an SU(2) gauge theory with dynamical fermions
• Numerical evidence for fractional topological objects in SU(3) gauge theory
• Instanton dominance over ${\alpha }_s$ at low momenta from lattice QCD simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$