  The spherical field formalism---a nonperturbative approach to quantum field
theory---was recently introduced and applied to phi^4 theory in two dimensions.
The spherical field method reduces a quantum field theory to a
finite-dimensional quantum mechanical system by expanding field configurations
in terms of spherical partial wave modes. We extend the formalism to phi^4
theory in three dimensions and demonstrate the application of the method by
analyzing the phase structure of this theory.
