Operator ordering and Feynman rules in gauge theories

The ordering of operators in the Yang-Mills Hamiltonian is determined for the $V_0=0\mathrm{}$ gauge and for a general noncovariant gauge $\chi \left(V_i\right)=0\mathrm{}$, with $\chi$ a linear function of the spatial components of the gauge field $V_{\mu }$. We show that a Cartesian ordering of the $V_0=0\mathrm{}$ gauge Hamiltonian defines a quantum theory equivalent to that of the usual, covariant-gauge Feynman rules. However, a straightforward change of variables reduces this $V_0=0\mathrm{}$ gauge Hamiltonian to a $\chi \left(V_i\right)=0\mathrm{}$ gauge Hamiltonian with an unconventional operator ordering. The resulting Hamiltonian theory, when translated into Feynman graphs, is shown to imply new nonlocal interactions, even in the familiar Coulomb gauge.