Fig. 4: Weak values with varying post-selection angle.

a Pointer shift along X (diagonal polarization component) as a function of post-selection angle with 1σ error bar, b Pointer shift along Y (due to coupling the spatial degree of freedom) as a function of post-selection angle with 1σ error bar. Only the photons detected in coincidence with the heralded photon are counted. The black dashed line in each plot represents the ideal theoretical weak value curves (weak value of the diagonal polarization component in a; the weak value of the spatial projection operator in b). The determination of the theoretical uncertainty bands (the blue-shaded regions) is given in the Methods section. The pointer shifts and the error bars are calculated using the raw data from the experiment, denoted by red dots and bars.