Hugo Cable

TL;DR: Different methods for quantifying the quantum and classical parts of correlations are among the more actively studied topics of quantum-information theory over the past decade as mentioned in this paper and different notions of classical and quantum correlations quantified by quantum discord and other related measures are reviewed.

TL;DR: It is shown how an idealized measurement procedure can condense photons from two modes into one and how, by feeding forward the results of the measurement, it is possible to generate efficiently superposition states commonly called N00N states.

TL;DR: In this article, the authors use wavelength-correlated and tuneable photon pairs to demonstrate how absorption spectroscopy can be performed with precision beyond the shot-noise limit and near the ultimate quantum limit.

TL;DR: In this article, the authors theoretically demonstrate the opposite with a set of quantum-measurement strategies that incorporate quantum discord and show that quantum discord makes it more difficult for precisions higher than the standard quantum limit to be achieved in measurements of the system's physical quantities.

TL;DR: In this paper, the authors show that a loss-tolerant quantum metrology is achievable with photon-counting measurements of the generalised multi-photon singlet state, which is readily generated from spontaneous parametric downconversion without any further state engineering.