Schwinger parametrization
Schwinger parametrization is a technique for evaluating loop integrals which arise from Feynman diagrams with one or more loops. Using the well-known observation that Julian Schwinger noticed that one may simplify the integral: for Re(n)>0. Another version of Schwinger parametrization is: which is convergent as long as and . It is easy to generalize this identity to n denominators. See also Feynman parametrization References Quantum field theory