Axial-vector two-body currents at finite momentum transfer in chiral EFT & Two neutrons in finite volume

Interactions of nuclei with external probes are crucial for understanding various processes. The nuclear currents involved can be described in the framework of chiral effective field theory, which provides a consistent treatment of both nuclear forces and currents based on the same chiral Lagrangian. We include the currents at the one-body level and the leading two-body currents, which we have derived for axial-vector currents at finite momentum transfers for the first time. Furthermore, I will discuss uncertainties in constraining low-energy constants from 3H beta decay and their impact on nuclear matter calculations. Finally, preliminary results for the two neutron system in a periodic box will be shown.