Rayleigh-Schr\"{o}dinger Perturbation Theory Based on Gaussian Wavefunctional Approch

TL;DR

This paper develops a Rayleigh-Schrödinger perturbation theory using Gaussian wavefunctionals to compute energies of vacuum and excited states, demonstrated through a $bbc$ field theory model.

Contribution

It introduces a novel perturbation approach based on Gaussian wavefunctionals for quantum field energy calculations.

Findings

Effective for vacuum and excited state energy calculations

Applicable to $bbc$ field theory model

Provides a new computational framework

Abstract

A Rayleigh-Schr\"{o}dinger perturbation theory based on the Gaussian wavefunctional is constructed. The method can be used for calculating the energies of both the vacuum and the excited states. A model calculation is carried out for the vacuum state of the $\lambda\phi^4$ field theory.