Correlation spectroscopy of condensed matter systems

We present experimental and theoretical evidence for the potential of the two‐particle spectroscopy to explore the electron‐electron interaction in condensed matter. The experiment consists of a single electron impinging onto a clean surface. Two electrons are then emitted simultaneously and their momentum vectors are resolved. The measured energy and angular pair correlations within the pair carry direct information akin to the electron‐electron interaction in the sample. We also point out that the presence of the Fermi sea leads to a damping, and a suppression of the range of the electron‐electron interaction.