  Nucleon properties are investigated in background electric fields. As the
magnetic moments of baryons affect their relativistic propagation in constant
electric fields, electric polarizabilities cannot be determined without
knowledge of magnetic moments. This is analogous to the experimental situation,
for which determination of polarizabilities from the Compton amplitude requires
subtraction of Born terms. With the background field method, we devise
combinations of nucleon correlation functions in constant electric fields that
isolate magnetic moments and electric polarizabilities. Using an ensemble of
anisotropic gauge configurations with dynamical clover fermions, we demonstrate
how both observables can be determined from lattice QCD simulations in
background electric fields. We obtain results for the neutron and proton,
however, our study is currently limited to electrically neutral sea quarks. The
value we extract for the nucleon isovector magnetic moment is comparable to
those obtained from measuring lattice three-point functions at similar pion
masses.
