Fourier path integrals, partial averaging, and the polaron problem

Publisher Website
Google Scholar
Abstract
We evaluate the Fourier path integral for an optical polaron by the method of partial averaging. Higher Fourier coefficients are taken into account by averaging with Feynman’s trial action, whereas the first N coefficients are treated explicitly by numerical integration. This method removes the Coulomb singularity in the effective action, yields lower bounds to the partition function, and systematically improves Feynman’s variational results. We present numerical results for the exact ground-state energy for small and intermediate values of the coupling constant.