The optical quantum entanglement experiments

F.J. Duarte

Hikida, Satoshi

Violations of Bell inequalities show that quantum entanglement produces nonclassical correlations between spatially separated systems. In quantum eraser experiments, interference is restored once distinguishability is removed. This highlights the essential role of distinguishability in quantum state transformations. However, it has not been recognized that a paradox can emerge using only conventional optical transformations of quantum states, and no experiment has been proposed to determine which of three mutually exclusive hypotheses outside the implicit assumptions of standard optical transformations and capable of resolving the paradox is realized in practice. Here we show that a paradox emerges in a configuration that reduces the distinguishability of an entangled state, and we propose an experiment capable of identifying which hypothesis is realized. Theory alone cannot determine which hypothesis is realized. Therefore, experimental verification is required. Regardless of the experimental outcome, the experiment would reveal an unrecognized property linking entanglement and distinguishability.

F. J. Duarte

F.J. Duarte

Eden Arbel, Noa Israel, Michal Belgorodsky +4 more

This paper presents an innovative experiment and theoretical framework designed for senior-level undergraduate students to explore quantum state tomography and Bell inequality tests. The experiment utilizes pulsed laser light and a carefully engineered optical system to emulate quantum entanglement, enabling students to investigate foundational quantum phenomena using accessible laboratory tools. Through practical measurements and simulations, students reconstruct quantum states and analyze correlations indicative of entanglement and non-locality. The setup includes polarization analysis across multiple measurement bases and culminates in the measurement of Bell’s parameter using the CHSH test. By combining experimental emulation with computational analysis, this approach provides a compelling educational bridge between abstract quantum theory and hands-on experiments, highlighting the conceptual and practical relevance of quantum entanglement in modern physics.

Yanhua H. Shih