Variational approach to Yang-Mills theory with non-Gaussian wave functionals

A general method for treating non-Gaussian wave functionals in quantum field theory is presented and applied to the Hamiltonian approach to Yang-Mills theory in Coulomb gauge in order to include a three-gluon kernel in the exponential of the vacuum wave functional. The three-gluon and ghost-gluon vertices are calculated using the propagators found in the variational approach with a Gaussian trial wave functional as input.