Temporal, matter-wave-dispersion Talbot effect

We analyze and experimentally demonstrate a new (temporal) Talbot effect, where a pulsed phase grating is applied to a cloud of cold atoms (Bose-Einstein condensate). In contrast to the usual (spatial) Talbot effect, our atoms gain kinetic energy when diffracted by that pulsed grating. The energy gain and the matter-wave-dispersion relation result in an exact:(no paraxial approximation) Talbot effect where the initial wave front is reconstructed at multiples of a "Talbot time" T-T. We demonstrate the Talbot effect by applying a second pulsed phase grating after a variable delay. When this second grating is applied at even (odd) multiples of T-T/2, it doubles (cancels) the effect of the first pulsed grating.