title: Analytic properties of two-photon scattering matrix in integrated quantum systems determined by the cluster decomposition principle.
abstract: We consider a general class of integrated quantum systems where photon-photon interaction occurs in a quantum device that is localized in space. Using techniques that are closely related to cluster decomposition principles in quantum field theory, we provide a general constraint on the analytic properties of a two-photon S matrix in this class of systems. We also show that the photon-photon interaction in these systems inevitably leads to frequency mixing and entanglement and that frequencies of the single photons cannot be preserved in these systems.
authors: Department of Physics, Stanford University, Stanford, California 94305, USA.
authors: Shanshan
authors: S
authors: Xu
authors: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors: Eden
authors: E
authors: Rephaeli
authors: Department of Electrical Engineering, Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.
authors: Shanhui
authors: S
authors: Fan