Comparison of some variational strategies used in field theory.

Recently two variational strategies have been applied to the standard and linear delta expansions for quantum field theories. These strategies, both of which improve the accuracy of the expansions, have the property that for N self-interacting fields at large N the lowest order 5 expansion improved by the variational strategy gives the exact large N result. In this note, we study, in the context of supersymmetric quantum mechanics, the numerical accuracy of the improved delta expansions when calculated to large order in 5 and compare them with the accuracy of the large-N expansion. We find that the usual delta expansion is most accurate, followed by the linear delta expansion. The large N expansion, analytically continued to N=1, is the least accurate method of the three.