Diagrammatic expansions for the Yang-Mills ground state

Starting from the finite-time action formulation of the temporal gauge, we derive diagrammatic rules for the perturbative evaluation of the Yang-Mills ground state wave functional and energy to all orders. The perturbative expansions are also easily reorganized into semi-classical expansions. As an application, the ground state wave functional through first non-trivial order is explicitly computed. We also speculate on the use of gauge invariance to improve perturbation theory. (orig.)