Measurement-based linear optics*

A major challenge in optical quantum processing is implementing large, stable interferometers. We offer a novel approach: virtual, measurement-based interferometers that are programed on the fly solely by the choice of homodyne measurement angles. The proposed continuous-variable cluster state architecture can be implemented on an unprecedented scale from compact experimental setups using either temporal or frequency modes. Our protocol minimizes noise due to finite squeezing. Furthermore, we show that this noise can be coaxed into appearing as pure photon loss per simulated optical element, where the efficiency of the interferometer is set by the overall squeezing parameter of the experiment. We compare our proposal to existing (physical) interferometers and consider its performance for BosonSampling, which could demonstrate postclassical computational power in the near future. We prove its efficiency in time and squeezing (energy) in this setting.

This talk is based on Phys. Rev. Lett. 118, 110503 (2017).