Quantum Monte Carlo calculations of electromagnetic transitions and magnetic radii of light nuclei with two-body $\chi$EFT currents*

We present a number of ab initio Quantum Monte Carlo calculations of electromagnetic observables for $A\le 10$ nuclei, which account for two-body effects due to the coupling of external photons with pairs of interacting nucleons. We use the realistic Argonne v18 two-nucleon and Illinois-7 three-nucleon potentials to generate the nuclear wave functions, and chiral effective field theory with pions and nucleons to construct the two-body electromagnetic current operators. Emphasis is on recent calculations of magnetic radii of light nuclei.