Nonlinear current and dynamical quantum phase transitions in the flux-quenched Su-Schrieffer-Heeger model

We investigate the dynamical effects of a magnetic flux quench in the Su-Schrieffer-Heeger model in a one-dimensional ring geometry. We show that even when the system is initially in the half-filled insulating state, the flux quench induces a time-dependent current that eventually reaches a finite stationary value. Such persistent current, which exists also in the thermodynamic limit, cannot be captured by the linear response theory and is the hallmark of nonlinear dynamical effects occurring in the presence of dimerization. Moreover, we show that for a range of values of dimerization strength and initial flux, the system exhibits dynamical quantum phase transitions, even though the quench is performed within the same topological class of the model.