Example image of eyePlorer eyePlorer map for 'Free field': Equations of motion Linear Partial differential equation Euler–Lagrange equation Lagrangian Quadratic Quantum field theory Wightman axioms Distribution (mathematics) Peierls bracket CCR and CAR algebras Minkowski space Vacuum state Canonical commutation relation Normal order Path-ordering Wick's theorem Gaussian fixed point Wave function renormalization Haag's theorem Mermin–Wagner theorem Critical dimension Yang–Mills existence and mass gap Creation and annihilation operators Gupta–Bleuler formalism Weinberg–Witten theorem Quartic interaction Canonical quantization Renormalization group