Comparisons are made between two different linked-cluster expansion methods, namely, the t expansion and the strong-coupling series expansion, as applied to the compact U(1) lattice gauge model in 2+1 dimensions. Connected moments of the Hamiltonian are calculated up to 28th order, extending previous results of Morningstar, and are used to form a t expansion. The t expansion is technically easier to calculate, and can give estimates of the axial string tension, which the strong-coupling series expansion cannot; but the strong-coupling series expansion gives better results for the mass gaps. © 1996 The American Physical Society.

• Received 18 July 1995

DOI:https://doi.org/10.1103/PhysRevD.53.1429