Perturbative Check of the Action and Energy Lattice Sum Rules

TL;DR

This paper verifies lattice sum rules for the quark-antiquark potential using perturbation theory, proving key identities, gauge invariance, and confirming the energy sum rule with high numerical accuracy.

Contribution

It provides the first perturbative checks of lattice sum rules, including the action and energy sum rules, and introduces methods for their validation.

Findings

The action sum rule relation is explicitly checked and validated.

The energy sum rule holds with good numerical accuracy up to next-to-leading order.

Gauge invariance of the Wilson loop expectation value is proven at this order.

Abstract

Lattice sum rules are checked using lattice perturbation theory. The action sum rule gives a relation between the quark-antiquark potential, its logarithmic derivative with respect to distance and the expectation value of the action; the energy sum rule expresses the potential as the sum of the energy in the gluon fields and of an anomalous term. Two different independent calculations of the quark-antiquark potential are presented, and the transversality of the gluonic vacuum polarization on the lattice is proven. The crucial part of the action sum rule is an identity whose explicit check using perturbation theory provides methods and results which are useful for checking the energy sum rule. Additionally, the gauge invariance of the expectation value of the Wilson loop up to next-to-leading order is proven. The possibility of restricting the expectation value of the action to one fixed time slice is discussed. The energy sum rule is checked perturbatively up to next-to-leading order and shown to be satisfied with good numerical accuracy. The various contributions to the quark-antiquark potential are analyzed, and the restriction of the expectation value of the sum over all spatial plaquettes (the energy in the magnetic fields) to one fixed time slice is examined.