Exact Floquet solutions in a periodically driven non-Hermitian parity-time symmetric two-level model

We investigate a type of periodically driven non-Hermitian two-level model with parity-time (PT) symmetry. It is shown that in a wide range of the model parameters, this model supports exact Floquet solutions. In particular, under certain parameter conditions, these exact Floquet solutions can characterize the transition from the unbroken PT-symmetric phase to the broken PT-symmetric phase. (paper)