In multi-path interference experiments, the different possibilities of partitioning reality into alternatives represented by probability amplitudes can lead to unexpected consequences. Here, the authors study the interplay between interference and which-source information in a frustrated SPDC system with three nonlinear crystals, showing that even in the case of full which-source information, it is impossible to ascribe a definite origin to photon pairs.
- Xinhe Jiang
- Armin Hochrainer
- Anton Zeilinger