Retardation, quasipotential equations, and relativistic corrections to the deuteron charge operator

Four different methods for handling the retardation of a single meson exchange in the nuclear force have been examined, together with the corresponding contributions to the deuteron charge operator. It is shown that to order ${\left(\frac{v}{c}\right)}^2$ these operators are all part of a single unitarily equivalent family. The Gross quasipotential equation is examined and relativistic corrections to the deuteron charge form factor are shown to be the same as those generated by the author's method, when converted to a common unitary representation. The same result has also been demonstrated for the folded diagram method. The asymmetric terms in Gross's Hamiltonian are shown to take the place of recoil graph contributions to the charge operator. These terms are necessary for Lorentz invariance and the "Gross correction" to the deuteron charge form factor.