Coherent acceleration of Bose-Einstein condensates

An overview is given on two coherent mechanisms to accelerate Bose-Einstein condensates with very little atom loss while preserving its monochromaticity. The first mechanism, based on the use of an accelerated optical lattice, can be interpreted as resulting from a sequence of Bragg resonances, which can lead to a remarkable preservation of the monochromaticity of the atomic sample under appropriate conditions. The second scheme uses a time-varying potential analogous to those used in the synchronous acceleration of charged particle.