Finite-size effects in Heisenberg antiferromagnets

Abstract
A system which exhibits antiferromagnetic order in the thermodynamic limit will, generically, have a symmetric ground state when the volume is finite. In this case the leading size dependence of various observables is controlled by soft magnons. The precise form of the finite-size corrections is worked out, and it is claimed that the expressions so obtained will be useful for the analysis of results obtained by Monte Carlo simulations or by exact diagonalization.