Morgan M. Weston

Experimental test of universal complementarity relations.

Complementarity restricts the accuracy with which incompatible quantum observables can be jointly measured. Despite popular conception, the Heisenberg uncertainty relation does not quantify this principle. We report the experimental verification of universally valid complementarity relations, including an improved relation derived here. We exploit Einstein-Poldolsky-Rosen correlations between two photonic qubits to jointly measure incompatible observables of one. The product of our measurement inaccuracies is low enough to violate the widely used, but not universally valid, Arthurs-Kelly relation.

Unconditional violation of the shot-noise limit in photonic quantum metrology

Interferometric phase measurement is widely used to precisely determine quantities such as length, speed and material properties1–3. Without quantum correlations, the best phase sensitivity

Heralded quantum steering over a high-loss channel

{\boldsymbol{\Delta }}{\boldsymbol{\phi }}

Discriminating nonorthogonal quantum states with minimum average number of copies (Conference Presentation)

Δϕ achievable using n photons is the shot-noise limit,

Detection-loophole-free heralded quantum steering over a high-loss quantum channel

{\boldsymbol{\Delta }}{\boldsymbol{\phi }}=1\,/\sqrt{{n}}