Generalized Heat Kernel Coefficients for a New Asymptotic Expansion (original) (raw)

The method which allows for asymptotic expansion of the one-loop effective action W = ln det A is formulated. The positively defined elliptic operator A = U + M 2 depends on the external classical fields taking values in the Lie algebra of the internal symmetry group G. Unlike the standard method of Schwinger-DeWitt, the more general case with the nongenerate mass matrix M = diag(m1, m2,. . .) is considered. The first coefficients of the new asymptotic series are calculated and their relationship with the Seeley-DeWitt coefficients is clarified.