Fig. 3: Measured entanglement-interference relations for different source coherences.

The diamonds, dots, stars, and triangles denote the fringe visibility, concurrence, source coherence, and distinguishability, respectively. The results are obtained with the preparation of the WPD’s superposition state \(\left\vert {W}_{0}\right\rangle\) delayed by a preset time. The conditional phase shift of the resonator induced by coupling to Q₁ is β = π/2. Squares denote evolution of the quantity \(\sqrt{{E}^{2}+{V}^{2}}\). The error bars represent the standard deviation of the measurements. For some data points, the error bar is smaller than the corresponding symbol.