"The interdisciplinary boundary between the fields of quantum information science, condensed matter, and ultra-cold atomic physics is at the heart of the new field of quantum engineering and will play an important role for the enhancement of our understanding of strongly correlated materials. One of the most important tools in this domain is optical lattices, which are periodic optical potentials – artificial ""crystals"" - created by counter-propagating laser beams. The dynamics of ultra-cold atoms in optical lattices is very similar to that found in solid state systems. In contrast to these, however, optical lattices have a high degree of purity, regularity, and tunability. They are therefore an ideal test bed for many condensed matter models such as those relevant for high-Tc-superconductivity and are a strong candidate for scalable quantum computation.The proposal will address two fundamental issues. Challenge 1: interface ultra-cold atoms in optical lattices with light. Although a non-destructive probe of the states in optical lattices would have great implications for the investigation of the rich many-body dynamics as well as for the field of quantum information processing it has never been implemented. In this project the experience of the applicant in non-destructive probing of room-temperature atomic gasses will be extended to optical lattices. Challenge 2: the manipulation and detection of single sites in an optical lattice represents a formidable technical challenge since the lattice spacing is of the order of 0.5um. In two hallmark experiments this resolution was achieved optically recently but the approach is very expensive and technically involved. Within this proposal a new way of achieving this resolution is introduced based on the interference of multiple coherent beams. Apart from technical simplicity it also offers enhanced sensitivity since the manipulation is controlled via the frequency – one of the most well-controlled properties in physics."