Wave-Particle Realism in Quantum-Controlled Interferometers Assisted by Entanglement

Delayed-choice experiments challenge classical intuitions by allowing the configuration of an interferometer to be chosen after a quantum system has already entered it. While these experiments support Bohr’s complementarity principle, the introduction of quantum control reveals that the manifestation of complementarity depends critically on the full physical context — including quantum correlations and the causal order of operations. In this work, we propose and analyze a modified entanglement-assisted delayed-choice experiment that maintains the same final visibility as the standard setup but reverses its causal structure. Here, we go beyond output statistics to examine how wave-particle realism evolves throughout the interferometer. Using a contextual realism quantifier, we show that wave and particle realism can be meaningfully assigned at intermediate stages with a clear connection with the final interferometric visibility. Specifically, our results show that modifying the causal order of operations and information structure, whether through entanglement tuning or post-selection, leads to significant variations in the wave-particle complementarity relation.