  The time-dependent numerical renormalization-group approach (TD-NRG),
originally devised for tracking the real-time dynamics of quantum-impurity
systems following a single quantum quench, is extended to multiple switching
events. This generalization of the TD-NRG encompasses the possibility of
periodic switching, allowing for coherent control of strongly correlated
systems by an external time-dependent field. To this end, we have embedded the
TD-NRG in a hybrid framework that combines the outstanding capabilities of the
numerical renormalization group to systematically construct the effective
low-energy Hamiltonian of the system with the prowess of complementary
approaches for calculating the real-time dynamics derived from this
Hamiltonian. We demonstrate the power of our approach by hybridizing the TD-NRG
with the Chebyshev expansion technique in order to investigate periodic
switching in the interacting resonant-level model. Although the interacting
model shares the same low-energy fixed point as its noninteracting counterpart,
we surprisingly find the gradual emergence of damped oscillations as the
interaction strength is increased. Focusing on a single quantum quench and
using a strong-coupling analysis, we reveal the origin of these
interaction-induced oscillations and provide an analytical estimate for their
frequency. The latter agrees well with the numerical results.
