Splitting, Rocking and Blinding Single Atoms
The wave properties of material particles are one of the most widely known features of quantum physics. Wave properties become apparent in diffraction and most strikingly in interference phenomena. The microscope image (Fig. 1 ) shows a coherently split single atom. I will discuss the necessary tools to realize this non- local situation: Tools for trapping, selectively addressing and transporting individual atoms, for storing and retrieving information from the atomic qubits. We have studied matter wave interferences at the single trapped atom level. With multiple interferences the quantum analogue of Brownian motion, the quantum walk, a concept of relevance in quantum information science, was demonstrated. We have furthermore obtained excellent control of atomic motion using microwaves, including cooling to the vibrational ground levels and the creation of single particle entangled states. In a separate line of experiments we have been able to read out the spin quantum states of individual atoms by dispersive methods. I will discuss the options to create correlated many atom quantum states based on the known protocols.