Adiabatic modulation of  driving protocols in periodically driven quantum systems

We consider a periodically driven system where the high-frequency driving protocol consists of a sequence of potentials switched on and off at different instants within a period. The possibility of introducing an adiabatic modulation of the driving protocol is investigated by considering a slow evolution of the instants when the sequence of potentials is switched on/off. By assuming that the slow and fast timescales in the problem can be decoupled, we derive the stroboscopic (effective) Hamiltonian for a four-step driving sequence up to the first order in perturbation theory and apply this approach to a rigid rotor, where the adiabatic modulation of the driving protocol is chosen to produce an evolving emergent magnetic field that interacts with the rotor's spin. The emergence of diabolical points and diabolical loci in the parameter space of the effective Hamiltonian is examined. Further, we study the topological properties of the maps of the adiabatic paths in the parameter space to the eigenspace of the effective Hamoiltonian. In effect, we obtain a technique to tune the topological properties of the eigenstates by selecting various adiabatic evolutions of the driving protocol characterized by different paths in the parameter space.