A light-front coupled-cluster method for the nonperturbative solution of quantum field theories

TL;DR

This paper introduces a novel light-front coupled-cluster method for solving quantum field theories nonperturbatively, avoiding common truncation issues and enabling more accurate calculations.

Contribution

It develops a new nonperturbative approach combining light-front quantization with coupled-cluster techniques, eliminating Fock-space truncation problems.

Findings

Effective Hamiltonian eigenvalue problem formulated in valence Fock sector

Method avoids Fock-space truncation and related divergences

Demonstrated in a light-front analog of the Greenberg--Schweber model

Abstract

We propose a new method for the nonperturbative solution of quantum field theories and illustrate its use in the context of a light-front analog to the Greenberg--Schweber model. The method is based on light-front quantization and uses the exponential-operator technique of the many-body coupled-cluster method. The formulation produces an effective Hamiltonian eigenvalue problem in the valence Fock sector of the system of interest, combined with nonlinear integral equations to be solved for the functions that define the effective Hamiltonian. The method avoids the Fock-space truncations usually used in nonperturbative light-front Hamiltonian methods and, therefore, does not suffer from the spectator dependence, Fock-sector dependence, and uncanceled divergences caused by such truncations.