Exact Green's function renormalization approach to spectral properties of open quantum systems driven by harmonically time-dependent fields

We present an efficient method and a fast algorithm to exactly calculate spectral functions and one-body observables of open quantum systems described by lattice Hamiltonians with harmonically time-dependent terms and without many-body interactions. The theoretical treatment is based in Keldysh nonequilibrium Green's function formalism. We illustrate the implementation of the technique in a paradigmatic model of a quantum pump driven by local fields oscillating in time with one and two harmonic components.