GitterQCD

GitterQCD is the term used to describe the numerical study of quantum chromodynamics on a discrete space-time lattice, or grid. In this approach the continuous four-dimensional space-time is replaced by a finite lattice with lattice spacing a and finite volume, enabling non-perturbative evaluation of QCD via statistical sampling of gauge field configurations.

Gauge fields live on the links between lattice sites, while fermion fields reside on the sites. The theory is regularized by lattice actions such as Wilson or improved clover actions for gauge fields, and various fermion discretizations (Wilson, staggered, domain-wall, or overlap). Observables are computed from ensembles of gauge configurations generated by Monte Carlo methods, typically using the hybrid Monte Carlo algorithm, with careful control of finite-volume, lattice-spacing, and chiral extrapolations to recover continuum physics.

GitterQCD is used to determine hadron spectra, decay constants, and form factors, and to study QCD thermodynamics, the equation of state, and topological properties of the gauge field. It provides a non-perturbative framework for testing QCD predictions and for exploring the behavior of quarks and gluons under extreme conditions.

Developed since the 1980s, lattice QCD has become a primary tool in high-energy physics. Technological advances in supercomputing and algorithm design have enabled simulations with physical quark masses and near-continuum spacings, improving precision in Standard Model parameters and providing insights into confinement and chiral symmetry breaking.

Related topics include lattice gauge theory, continuum QCD, Monte Carlo methods, and hadron phenomenology.