On the non-local heat kernel expansion

Heat Kernel Expansion for Semitransparent Boundaries

We study the heat kernel for an operator of Laplace type with a δfunction potential concentrated on a closed surface. We derive the general form of the small t asymptotics and calculate explicitly several first heat kernel coefficients.

Heat-kernel expansion on non compact domains and a generalised zeta-function regularisation procedure

Heat-kernel expansion and zeta function regularisation are discussed for Laplace type operators with discrete spectrum on non compact domains. Since a general theory is lacking, the heat-kernel expansion is investigated by means of several examples. Generically, it is pointed out that for a class of exponential (analytic) interactions, the non compactness of the domain gives rise to logarithmic...

Heat Kernel Expansion in the Covariant Perturbation Theory

Working within the framework of the covariant perturbation theory, we obtain the coincidence limit of the heat kernel of an elliptic second order differential operator that is applicable to a large class of quantum field theories. The basis of tensor invariants of the curvatures of a gravity and gauge field background, to the second order, is derived, and the form factors acting on them are obt...

The heat kernel on R

An Improved Heat Kernel Expansion From Wordline Path Integrals

The one–loop effective action for the case of a massive scalar loop in the background of both a scalar potential and an abelian or non–abelian gauge field is written in a one–dimensional path integral representation. From this the inverse mass expansion is obtained by Wick contractions using a suitable Green function, which allows the computation of higher order coefficients. For the scalar cas...