Reaching the continuum limit in lattice gauge theory - without a computer

The scaling slope of the anti-symmetric mass gap M of compact U(1)(2+1) lattice gauge theory is obtained analytically in the Hamiltonian formalism using the plaquette expansion. Based on the first four moments of the Hamiltonian with respect to a one-plaquette mean field state the results demonstrate clear scaling of M at and beyond the transition from strong to weak coupling. The scaling parameters determined agree well with the range of numerical determinations available. (C) 2002 Elsevier Science B.V. All rights reserved.