Nondiagonal Values of the Heat Kernel for Scalars in a Constant Electromagnetic Field

Resumo

An original method for finding the nondiagonal values of the heat kernel associated with the wave operator Fourier-transformed in time is proposed for the case of a constant external electromagnetic field. The connection of the trace of such a heat kernel to the one-loop correction to the grand thermodynamic potential is indicated. The structure of its singularities is analyzed.