Neutron time interferometry

We compare a "Mach-Zehnder interferometer in time" for cold neutrons with i ts well-known spatial counterpart and demonstrate the intimate connection b etween space and time for both setups. Further, we outline a combined space -time interferometer, which coherently splits a wavepacket in longitudinal and lateral direction. On the way towards time interferometry "neutron comp uter holography" seems to be an attractive application. It allows the three -dimensional reconstruction of an object from the scattered intensity, but in contrast to holography with light, there is no need for a reference wave . On the other hand, the possible resolution is worse than in the light cas e.