Echoes in optical lattices

Summary form only given. The investigation of coherent superposition states for atoms interacting with external potentials allows a completely new class of experiments directed towards coherent trapping and guiding of neutral atoms. In addition, the process of decoherence, i.e., the collapse of superposition states, is one of the basic concepts for our understanding of the connection between classical and quantum physics. We study the creation and decay of superpositions of different components of the center-of-mass wavefunction of rubidium atoms in a one-dimensional near-resonant optical lattice. This makes it possible to gain insight into the dependence of decoherence processes on the coupling of the atoms to the light field. We discuss the dependence of the wave packet oscillations and echoes on experimental parameters (potential depth, light intensity and detuning, time delay, size of the shift, etc.). We compare our experimental results with numerical simulations of the echo effect. The observation of this new effect in the coherent wave packet motion of atoms trapped in optical potentials will allow us to selectively study the decoherence process and measure the decoherence time in regimes where this was previously impossible.