Speaker: Brad Christensen, University Illinois Urbana-Champaign
Abstract: A loophole-free Bell test has been sought to conclusively answer a central debate of 20th century physics: can an alternative theory to quantum mechanics (i.e., a local realistic theory) explain entanglement's seemingly nonclassical correlations? Here, we will present the details of our loophole-free Bell test, where we use a high-quality and high-efficiency source of entangled photons to achieve a p-value as low as 5.8 x 10-9 while maintaining space-like separation of all relevant events. Furthermore, we will briefly discuss the generalized theory of nonlocality, which we use to experimentally demonstrate the counterintuitive effect of more nonlocality with less entanglement, present the most nonlocal correlations ever reported and use these correlations to bound the predictability of any post-quantum theory, and achieve quantum correlations requiring the use of complex qubits. From this small sample of measurements, we hope to show the strength of Bell tests in probing current and future theories.