Novel method for computing the tensor multipole expansion of two nucleon currents in momentum space.

Two nucleon currents are a critical ingredient in predictive calculations of electroweak phenomena in nuclei such as beta-decay, neutrino-nucleus scattering, and neutrinoless double beta decay.  However, their complicated mathematical structure has rendered these currents prohibitively difficult to include in modern basis-expansion many-body approaches, such as coupled cluster theory or in-medium similarity renormalization group, without severe approximations.  We have developed a novel method to compute and represent the multipole expansion of these currents in mixed momentum-spline partial wave basis.  We will present an overview of the formalism as well preliminary results using the full/non-approximated momentum dependence of the current.