  Behavior of quantum liquids is a fascinating topic in physics. Even in a
strongly correlated case, the linear response of a given system to an external
field is described by the fluctuation-dissipation relations based on the
two-body correlations in the equilibrium. However, to explore nonlinear
non-equilibrium behaviors of the system beyond this well-established regime,
the role of higher order correlations starting from the three-body correlations
must be revealed. In this work, we experimentally investigate a controllable
quantum liquid realized in a Kondo-correlated quantum dot and prove the
relevance of the three-body correlations in the nonlinear conductance at finite
magnetic field, which validates the recent Fermi liquid theory extended to the
non-equilibrium regime.
