Instanton count

Instanton count refers to the number of specific solutions—called instantons—that exist in a quantum field theory, especially in non-abelian gauge theories like quantum chromodynamics (QCD). These solutions represent tunneling events between different stable states of a field, playing a crucial role in understanding phenomena like symmetry breaking and strong force dynamics. The count indicates how many such instanton configurations contribute to the theory’s behavior. Mathematically, counting instantons helps in computing quantities like tunneling rates and vacuum structure, providing insight into the non-perturbative aspects of quantum fields.