Resonant Dynamical Casimir Effect in Waveguide-coupled Qubit Arrays

We have developed a theory of parametric photon generation in the waveguides coupled to arrays of qubits with temporally modulated resonance frequencies. Such generation can be interpreted as a dynamical Casimir effect. We demonstrate numerically and analytically how the emission directionality and photon-photon correlations can be controlled by the phases of the modulation. The emission spectrum is shown to be strongly dependent on the qubit anharmonicity parameter. Single- and double-excited state resonances have been identified in the emission spectrum.