  We propose a novel experimental probe for cold atomic gases analogous to the
scanning tunnelling microscope (STM) in condensed matter. This probe uses the
coherent coupling of a single particle to the system. Depending on the
measurement sequence, our probe allows to either obtain the \emph{local}
density, with a resolution on the nanometer scale, or the single particle
correlation function in real time. We discuss applications of this scheme to
the various possible phases for a two dimensional Hubbard system of fermions in
an optical lattice.
