Fig. 4.

Interferometric measurement of inertial forces. (A) An inertial force is applied during the hold time by accelerating the lattice by up to 5 g for a duration of t_acc = 20 μs; the paths are merged while in the inertial frame at velocity v_max. (B) Phase Φ_acc shows a linear dependence on acceleration for 4, 12, and 20 shifts. The solid lines show the prediction by a simple model (see text) without free parameters where the acceleration exerted by means of a piezoelectric transducer has been independently calibrated. Systematic deviations from the linear model are expected to occur because of mechanical resonances and nonlinearities in the response of the transducer. Phase offsets of the datasets have been subtracted. (Inset) Constant contrast at given separation indicates that acceleration causes no decoherence. Error bars show one SEM uncertainty.