Abstract

The collapse of the Kondo regime, followed by a delayed THz pulse emission upon its recovery has been observed in recent THz spectroscopy experiments on heavy-fermion compounds such as CeCu$$Au${x}$. This work provides a theoretical framework to describe the non-equilibrium dynamics by employing the Anderson lattice model, time-dependent non-equilibrium dynamical mean-field theory, and the non-crossing approximation. We identify two key non-equilibrium mechanisms that play pivotal roles in the collapse and subsequent revival of Kondo coherence. First due to the pulse intensity the hybridization between localized $f$-electrons and conduction electrons increases, shifting the system to a mixed-valence regime, leading to a rapid destruction of the Kondo state. Second, while the distribution function and the single-particle peak recover quickly, the Kondo peak requires significantly more time due to the intrinsic low-energy effects associated with Kondo physics. Additionally, we confirm the system’s ability to emit a non-superradiant delayed pulse upon the recovery of the Kondo regime, confirming the many-body origin of the experimentally observed delayed pulse.