Testing Local Realism with Bell’s Inequality

Thumbnail Image
Robertson, Jake
Zheng, Han
Nedvidek, Brendan
Nish, Grant
Chen, Zoe
In this experiment, we constructed a single-channel Bell test to demonstrate the non-local nature of quantum mechanics. The apparatus was used to calculate Bell’s inequality(S) for entangled particles and show the violation of local realism. The experiment used a 405nm laser shun through a Beta-Barium Borate(BBO) crystal to create entangled photon pairs in a process called parametric down-conversion. Using interferometry techniques, the entangled photons were directed into two collimators both connected to a single-photon coincidence counter through fibre optic cables to detect entangled photon coincidences. The final part included the placement of linear polarizers in front of the collimators to take data for the calculation of S. The predicted result was that Bell’s inequality would be violated thus confirming the non-locality feature of entangled particles. Contrary to predictions, we found that Bell’s inequality was not violated for the measurement we took. This result is attributed to insufficient alignment as the non-locality in the quantum realm is a well-observed phenomenon.
External DOI