Adaptive strategy for joint measurements
: Uola R, Luoma K, Moroder T, Heinosaari T
Publisher: AMER PHYSICAL SOC
: 2016
: Physical Review A
: PHYSICAL REVIEW A
: PHYS REV A
: ARTN 022109
: 94
: 2
: 9
: 2469-9926
DOI: https://doi.org/10.1103/PhysRevA.94.022109(external)
We develop a technique to find simultaneous measurements for noisy quantum observables in finite-dimensional Hilbert spaces. We use the method to derive lower bounds for the noise needed to make incompatible measurements jointly measurable. Using our strategy together with recent developments in the field of one-sided quantum information processing we show that the attained lower bounds are tight for various symmetric sets of quantum measurements. We use this characterisation to prove the existence of so called 4-Specker sets, i.e. sets of four incompatible observables with compatible subsets in the qubit case.