An illustration of the light-front coupled-cluster method in quantum electrodynamics

TL;DR

This paper applies the light-front coupled-cluster method to quantum electrodynamics to compute the electron's anomalous magnetic moment nonperturbatively, extending beyond the Schwinger result with numerical techniques.

Contribution

It introduces a nonperturbative Hamiltonian approach using the exponential-operator technique in light-front QED, including an unlimited photon state space.

Findings

Perturbative solution reproduces Schwinger result

Nonperturbative solution sums corrections to all orders in nd includes additional physics

Numerical techniques enable complex calculations in light-front QED

Abstract

A field-theoretic formulation of the exponential-operator technique is applied to a nonperturbative Hamiltonian eigenvalue problem in electrodynamics, quantized in light-front coordinates. Specifically, we consider the dressed-electron state, without positron contributions but with an unlimited number of photons, and compute its anomalous magnetic moment. A simple perturbative solution immediately yields the Schwinger result of \alpha/2\pi. The nonperturbative solution, which requires numerical techniques, sums a subset of corrections to all orders in \alpha\ and incorporates additional physics.