Quantum Field Theory on the Lattice is essential for the theoretical studies of Quantum Field Theories where coupling constant is not small. In this case, most of hadronic properties can not be calculated by conventional perturbative expansion via summation of Feynman diagrams. A prime example in the Standard Model is Quantum Chromodynamics, which is the fundamental theory of interactions between quarks and gluons. Quantum Chromodynamics on the Lattice is based directly on the Chromodynamics and the only parameters are those that already appear in the fundamental theory: quark masses and the strong coupling constant. In this case, the hadron properties are calculated by numerical evaluation of Feynman path integrals on finite and discretized space-time - i.e. lattice. Several interesting theories beyond the Standard Model also contain new forms of strong interactions that require non-perturbative approaches like lattice simulations.
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