Compression of metrological quantum information in the presence of noise

Abstract

In quantum metrology, information about unknown parameters θ=(θ1,...,θM) is accessed by measuring probe states ρθ. In experimental settings where copies of ρθ can be produced rapidly (e.g., in optics), the information-extraction bottleneck can stem from high postprocessing costs or detector saturation. In these regimes, it is desirable to compress the information encoded in ρθ - n into m