Fig. 6: Fidelity between the distributions for the z-basis measurement at time t3.
The error bars represent the standard error of the mean. Red dots refer to the fidelity between the marginal distribution from theory (p(x3)) and the experimentally obtained three-time QPD (\({p}_{{{\rm{exp.}}}}({x}_{3})={\sum }_{{x}_{1},{x}_{2}}{p}_{{{\rm{exp.}}}}({x}_{1},{x}_{2},{x}_{3})\)). A fidelity of 1 refers to two distributions are equal. The blue line refers to the theoretical fidelity between p(x3) and pproj.(x3) when projective measurements are performed at times t1 and t2. The blue dots refer to the corresponding experimental result. The pink shaded area indicates the advantage of the snapshotting protocol compared to projective measurements.
