Frequency Shifts Induced by Field Gradients in Muon $g-2$ Experiments
  Two prominent efforts aimed at probing beyond Standard Model physics, searches for a neutron electric dipole moment (EDM) and measurements of the muon $g-2$ anomalous magnetic moment, employ spin precession techniques. In the most recent neutron EDM experiment, frequency shifts induced by magnetic field gradients and $\mathbf{E} \times \mathbf{v}$ motional fields were a significant source of systematic error. We consider the possibility of a similar effect in the most recent muon $g-2$ experiment, and find that such an effect could potentially be as large as $\sim 1$ ppm fractional error, to be compared with the reported $\sim 0.5$ ppm error. 
N. Nouri, M.A. Brown, R. Golub, B. Plaster
nucl-ex hep-ex hep-ph