A perturbation inspired variational technique

Abstract

The paper discusses how the Variationally-Improved Perturbation Theory (VIPT) scheme of approximation in quantum mechanics can be improved convergence-wise if one uses for variational trial functions the perturbative series with variational parameter, so that one is effectively doing variational calculations directly on the high-order perturbative series for energy. The result optimizes the high-order energy directly and thus represents a significant improvement over the VIPT procedure.