Abstract:

The manipulation and detection of individual quantum excitations forms the basis of modern quantum optics experiments. However, most of these experiments have been restricted to systems composed of only a few particles.
In recent years, tremendous experimental progress has been made in probing strongly interacting many-body systems at the single-particle level. This was achieved by the single-site- and single-atom-resolved imaging and manipulation of quantum gases in optical lattices.
I will review these developments and present, in more detail, a few chosen experiments: The single-site-resolved detection of correlation functions [1] and the quantum dynamics of a mobile spin impurity [2]. These experiments show that quantum fluctuations of the many-body system become directly visible and that impurities can be implanted and studied with unprecedented control. However, the method has its limits [3], which I will analyze in the last part of talk. I will also outline future experiments that could overcome some of the restrictions.