The Coupled Cluster Method in Hamiltonian Lattice Field Theory: SU(2) Glueballs

TL;DR

This paper applies the coupled cluster method to compute the glueball spectrum in SU(2) lattice gauge theory in two spatial dimensions, achieving results consistent with Monte Carlo simulations.

Contribution

It introduces the coupled cluster method for Hamiltonian lattice gauge theory and demonstrates its effectiveness in calculating glueball spectra for SU(2).

Findings

Mass ratios agree with Monte Carlo results

Good scaling behavior observed

Effective truncated basis used for spectrum calculation

Abstract

The glueball spectrum within the Hamiltonian formulation of lattice gauge theory (without fermions) is calculated for the gauge group SU(2) and for two spatial dimensions. The Hilbert space of gauge-invariant functions of the gauge field is generated by its parallel-transporters on closed paths along the links of the spatial lattice. The coupled cluster method is used to determine the spectrum of the Kogut-Susskind Hamiltonian in a truncated basis. The quality of the description is studied by computing results from various truncations, lattice regularisations and with an improved Hamiltonian. We find consistency for the mass ratio predictions within a scaling region where we obtain good agreement with standard lattice Monte Carlo results.