Competing Energy Scales and Quasiparticle Dynamics in a Driven Kondo Impurity System*

The ultrafast pump-probe techniques are used to probe the elementary excitations and its energy scale in materials. Recent study [Nat. Pays. 14 1103 (2018)] shows the collapse and revival of the Kondo correlations from terahertz reflectivity measurement. Here we propose a model study as a proof of principle to first determine the corresponding Kondo energy scale by using the matrix product state to simulate the Fermi-Bose-Anderson impurity model, which is a good starting model for the study of Kondo lattice model. In equilibrium, the model displays a quantum critical point that captures the competition between RKKY interaction and Kondo coupling in the underlying system. As a laser pump pulse is applied to the system, our nonequilibrium simulations show that the driven system exhibits qualitatively different response, which is related to the competing energy scales. Our results benchmark the competing energy scales in a Kondo impurity system and provide new insight on the behavior of the critical quasiparticle in heavy fermion compounds.