Toward a Loophole-Free Bell Inequality Violation with Barium Ions

Abstract

The successful generation of ion-photon entanglement with a singly-trapped Barium ion and the photon it spontaneously emits is reported along with the current progress and technical details for extending this work to a loophole-free test of Bell's Inequality. The achieved ion-photon entanglement fidelity is .84(1) and a violation of the CHSH Bell Signal is shown to be greater than $8\sigma$. The utilization of a novel trap type and a pulsed laser for excitation is discussed for improvement of the rate of heralded ion-ion entanglement. A side project measuring the branching fraction of the 5D$_{5/2}$ level in $^{138}$Ba$^{+}$ is also discussed.