Measurement of Tan’s contact in SU(N) fermions

Contact interactions play a fundamental role for understanding correlated quantum systems from microscopic models. For example, the 1/k4 momentum tail, the weight of which is known as Tan's contact, reveals a set of universal relations in interacting atomic systems. Nevertheless, the experimental measurement of contact has still remained unexplored for multi-component fermions with high spins. Here, we report on the measurement of s-wave contact parameter in a cold spin-balanced gas of 173Yb atoms with SU(N) symmetry. The high-momentum tail is recorded after time-of-flight expansion, and Tan's contact is directly quantified with a tunable number of spin component N without changing the number of atoms per component. We experimentally verify the linear increase in the contact with N providing experimental confirmation of the SU(N) interaction. Furthermore, we investigate the momentum distribution of SU(N) fermions at the low momentum regime showing that multi-component fermions with large N exhibit a more bosonic behavior. Our measurement directly reveals the interaction effect in a multi-component Fermi gas with SU(N) symmetry, and paves the way for study of many-body physics with high spins.