Non-Gaussian State Generation from Linear Elements via Feedback

Abstract

We present a feedback scheme to produce quantum non-Gaussian states from linear optical elements. Instead of traditional additive control methods, we introduce a mutiplicative feedback control and apply it to the deterministic generation of quantum superposition states. The protocol of feedback control is based on quantum nondemolition measurement of a quadrature, multifeedback structure, and Lyapunov stability for feedback design.